I' m not paid to say this - its rare for me to endorser anyone or anything. - it takes something special. ABSOLUTELY check these guys out!!! Brand new company, with the coolest thing I have seen in the auto market since the 5 speed swap!!! progressionignition.com/
My daily driver is a 72 f250 , all your videos are so helpful in making my Holley run smoooooth .... down these Phoenix roads ... always looking forward to them . Keep up the great work ...
Thanks so much! If a wore out tired old 181k mike 390 can pull hard, anything can. Timing is the single most misunderstood and neglected tuning item of all time!!! It makes a massive difference!
I've always used a vacuum gauge when setting initial timing. Like you I plug it into the ported port and advance it until I get the highest vacuum then back it off slightly and lock it down, bob's your uncle. Always ran beautiful.
Luke. I’m sending out a personal “Thank you”. I’ve watched many of your videos on timing and carb adjustments and taken that to my carbureted marine 454. I install a fuel pressure regulator with a return line, squared my transfer slots (edelbrock 750) and adjusted my timing to get my idle set right. The thing starts amazing now. Runs absolutely PERFECT and gained about 2 mph on the top end. 👍👍👍👍
It is refreshing to see a somewhat younger technician with such an understanding of old school technologies and how they relate to one another, as well as being able to explain it simply and completely.
Always thankfull for your videos, spreading the knowledge is gonna keep our old cars on the road and off the junkyards, and therefore helping our analog car culture to stay alive.. Thank you 👍
Hi Luke. I am running a holley 600 DP. On a stroker 331. My ported port is blocked off with a flush Ailen screw. I am trying to locate a screw in vacuum nipple where can I locate one have a suggestions Guido 👍🏼
I daily a 1984 Ford Ranger. Your videos (Despite you dont have much motorcraft carb videos) taught me a lot on getting my engine to run right! I plan on doing a engine rebuild soon!
thank you,,,,,,for your generous time.........I'm fortunate to watch your video seminars , you relay the information like a professional university teacher......I've studied many books and have a hard time relaying to others what I have learned...You sir have a great intellect and talent...............I'm a Drag Racer....I've been studying articles, and books since 1965 , as I am 69 years young.............TL
Thank you, your videos are QUITE useful. We bought a 1955 Thunderbird that has a 1957 312 installed in it. Used your video about adjusting clutches to fix the issue with our's. It was NOT adjusted at all since the clutch had been installed years ago. Our car has a Holley 1848 just like your truck and has a Mallory Unilite distributor in it that has no vacuum advance. According to the tach it idles at 1400 rpm's and still needs the clutch feathered a bit on the off in first to avoid stalling. Manifold vacuum measured at the manifold is 17.
Just wanted to throw out a big thanks to you ! I have my 79 302 equipped 2wd in the garage & it’s never really ran the greatest since a rebuild I’m positive with some proper tuning it’ll purr again soon
This is great! I can't tell you how many people I've asked about the abrupt loss of advance when plugged into manifold vacuum. This all makes perfect sense and I can't wait to try it out after my engine is back together!
I just had a cam and lifters put in my 400. I couldn't get it to idle right for anything! I watched your videos on ignition timing and the Edelbrock tips in this vid, since I'm running a 600cfm Eddie. Your advice has this thing idling correctly, and it pulls smooth with no hesitation at all. I owe you a venison dinner!!
Let me start by saying i think youre a super intelligent guy who knows what hes doing and does a good job getting information across. I do want to follow it with saying i completely disagree with you about ported / manifold vacuum. The best way ive found is set up like you say, neutral for manual, gear for auto, vacuum gauge on manifold vacuum, vacuum advance unhooked. Increase static / base timing until you find the highest vacuum point (adjust rpm back to spec as needed). THAT number is where the engine is most efficient and that number is what your idle timing should be. Generally this number is anywhere from high teens to low 30s depending on cam, compression, and altitude. Now, we all know that very few engines are going to start with 28* of initial timing, and even if they did as soon as you put a load on it its going to ping like crazy. So lets set our base timing back to something reasonable, generally speaking, camshaft duration and overlap is going to dictate this number for us (theres charts on the interwebs). In the case of my cam, 18* works pretty well, then to that, we add our vacuum advance, which in my case is ~14* for a total idle timing of 32*. This is why manifold vacuum is superior. You say that manifold vacuum retards timing as soon as you crack the throttle, it does, but it never going to be lower than it was on ported. You have all the advantages of the engine having the timing it wants at idle, with none of the disadvantages, snappy throttle, cooler idle, quieter, etc. It is especially useful for engine with large cams that have a hard time reaching an acceptable idle without over exposing the transition, opening the secondaries, or drilling bypass holes. Ported vacuum exsists because of CARB and the EPA, retarding the timing at idle increases idle exhaust temperature which cuts down on hydrocarbons, warms the engine up faster, and produces less NOX. I will get off the soapbox but i will add that not all engine should necessarily run manifold vacuum. Stock engines generally dont benefit as much because there is less benefit to be had. In the case of a daily driver for instance, the faster warmups are nice, but for performance, after having tried both multiple times, there is only one answer, and it isnt ported.
A quick story on ignition timing and advance curves. When I first assembled a Pontiac 455 years ago it seemed sluggish off idle and didn't have the torque I was expecting... until one day I took off from a stop light and at about 20 mph it lit the rear tires and felt like a 150 shot of nitrous. It turned out that the mechanical advance weights in the new distributor had been sticking and finally let loose. I hadn't checked the curve, figuring that a new distributor would be functioning properly. Lesson learned.
Might be a stretch! It would be awesome if you did a video series on a A-Z engine rebuild. Like what to do, how to do it, average cost of the rebuild kits and what you NEED to replace, and the cost of getting the machine work done, Finally. Putting it all together, setting the timing, getting the engine in the truck or car with the carb all setup and running right. Id like to see something like that! Especially from you! Since you've got a lot of knowledge on that subject!
I’ve been arguing the timed port thing since the 80s with my buddies. You’re doing the hobby a lot of good . I always look forward to seeing your videos!!
Thanks so much! There’s a false belief out there that it’s associated with emissions. My 64 galaxie is factory ported with no PVC or anything else smog. I highly doubt that the ported port was an attempt at smog control in 64! Even if it is, it can be utilized to get the correct mechanical timing on an engine! A lot of stock timing curves are lazy!
I had a friend who started building engines when he was like 10. My foundation for engine building and tuning came from him. Using ported vacuum was the first thing he stressed about setting idle and tuning carbs.
Man, it’s extremely cool - meeting the guy made it all the better “I was pissed I couldn’t do exactly what I wanted, so I made something that gave me the ability to” Straight badass
Thanks for sharing the information. I'm currently working on a 76 f150 (360) dealing with egr and vaccum stuffages. I may pull the carb off again after watching several of your vids and double checking the transition slots. I had vaccum at idle apparently at the egr port. Still working on adjusting things to get it running better, for a 2bbl, eventually going to turn it into a 445 stroker. Still appear to have egr issues, but I will deal with that later. I also put in a digital dash it is a great addition and I like the way it looks and gives me more information on what the engine is doing. I noticed in one of your other vids you have a af guage. Do you have the stock exhaust with it tapped into the pipe where they meet or are you running dual exhaust and just have one pipe tapped?
Very helpful and informative video, I definitely appreciate the time effort and patience that you put into these video guides. Your truck deffently has a very nice sound exhaust!!
Oh! I always ran 10 degrees initial and the manifold vacuum to the HEI with what ever it came with. Then promptly fiddled with the carb settings. No wonder it was never a good feel. I really enjoyed the Engine Masters episode about total timing, really got me to thinking. Your episode really got me to thinking about the transition. What about a performance cam with questionable idle vacuum? Still the same principle?
A high lift cam will have less cylinder pressure at idle, which will require more timing! Usually those land at 16-18 degrees advance. Just some background understanding, the overlap at low engine speed bleeds off compression - less compression means a slower burn time which calls for more timing to burn the mixture at the right time in the stroke!!! Conversely, what they give up down low they provide up top! The Overlap creates a scavenging effect which draws the next cylinder charge in at higher rpm where a lower rpm cam will run out of breath!
@@ThunderHead289 oh, oh! I see now. I've just never had enough initial timing and was hooked up to manifold vacuum on the distributor. No wonder it's crap on tip-in. I cruched the problem with faster idle, wondering why the mixture screws weren't responding. Too mucho transfer sloto! 😬 I feel better now watching your tuning series that I can start at square one and dial the setup in. Thanks!
@@ThunderHead289 in that situation, would you dial in quite a bit of initial advance, and then limit how much total with stop bushings? I have a 10:1 302 with Bennett Racing ported heads and a 230/240@.050 camshaft. Edelbrock Performer RPM and 650 mechanical secondary in my 1964 Fairlane. Only makes 8-10 inches of vacuum at idle. Sounds like my best bet is to square the transfer slots, and use timing to get the idle where I want, then limit mechanical advance until I total at 34 degrees or so? I already have to run the Holley throttle plates with .093 holes on the primaries.
Hey Luke, great job with the videos - very informative and teaching to anyone even remotely interested in old school tech and cars. A question - Got my grandpa's old Fiat from 1964 that I've slowly been building for a couple of years and in a week or so it's at the point of starting up after I get the fuel lines done. Any tips on what last minute things to do before I crank it? The last time it ran was back in 2012, at that time it started after 1 minute of cranking with old oil and having just sat for 25 years. The car's been sitting in a warm garage for the last 45 years. Oil / fluids? Anything else? There's still some 70's fuel in the tank lol
@ThunderHead289 I'm so glad you make these videos. Not everyone wants to drive their classic like a freakin race car! I really appreciate what you say about timing and ported vacuum. I'll bet you if you examine the shop manuals of countless classics for the initial setup of ignition and carburetor systems, ported vacuum will always be hooked up to the advance mechanism of the distributor. Those engineers didn't know everything, but they weren't stupid either.
Just as long as a guy advances his initial timing, all will be well. Obviously an engine that requires notable advance will fare better with a distributor recurve to compliment this improvement
Been running manifold vacuum on my 73 f250 highboy just because that's the way the 2 barrel was set up on it when I got it, now it has a AFV elderbrock 650, I will try this , something to do during lock down
To put it in perspective - I tried it both ways for fun, I’ve gotten a whole one way trip to work better in a week. Which is notable since I live 40 minutes from where I work!!!
I know that can be the stupidest ask but is the horns of the truck working I mean the clacson? I'm asking that because I collect classic clacsons and fix them. I saw four of them on the truck two air horns and two electric I don't know why this truck have four horns if it's needing only two or may two of them aren't working. So are they working?
Hey Mate...Can I assume you got your 14 degrees timing sorted whilst the vacuum line was connected back on the ported vacuum between the distributor vacuum advance? OR did you adjust your timing and idle whilst they where NOT connected? ( and plugged the holes) It would also be good to show the viewers how you connected the vacuum gauge (to see RPM) During your Timing Adjustments....for those who don't know how... just my two cents.. Good video!
I’m probably asking a dumb question but I’m a little unclear on adjusting the transfer slots. Are you saying to just do the dance between your idle speed, idle mixture, and timing and that if you do all that and aren’t pulling vacuum at idle off the ported port, then you should be set correctly as far as the slots? So if I get set and have a little vacuum, I should back off my idle speed screw and give a little more timing?
Hello, we just bought a Vanguard R.V. with the 1986 Ford E-350, 460 3 speed. Do you recommend removing all the EGR components and plugging the exhaust manifolds? There's no cat in it. If so, tuning afterwards would make sense, right? And there's a lot of potential problems with ICM, where some have a spare one on hand, much cheaper than buying a MSD or Progression Distributor. But if we put in a Progression distributor than would we have the need to buy a timing light and other gauges? Definitely the vacuum gauge. But a timing light also would be cheaper than a new Progression distributor. So, what gauges to you recommend for the interior, for the minimalist. ;-) Thank-you.
I have a 32' Ford PU with a 51' Merc. 255ci engine in it. Is there anyway I can apply your video to it? Stock is 7.5 to 8.5 deg. @ 2000rpm. I am running the stock Holly "tea pot" carb. and don't want to change. A dist. rebuilder recommends 18deg. @ 2500, mine will ping at that setting. Should I do "old school" and adv. until it pings, then back up a deg. or 2. These dist. are unusual as to where they take the vacuum from. You cannot run multi. carbs with a stock dist. Have watched 4 or 5 of your videos, VERY informative and to the point. Thanks frank
Ok ill try it, i dont remeber why i set mine the way i did. Ive all way set the timing but ear, then made it idle with a flat head. Three things no shakey, slow, and not smell like gas, then it idles nice...
All is good, ported vacuum how many guys argue about that. I done about the same with vacuum gauge to prove the point. But get rid of the plastic fuel filter.. lol 😆
I've run both ported and manifold vacuum advance and for my application I chose manifold vacuum for vacuum advance. Mostly because it idles much better in the cold with more timing once the choke comes off. I can't run anymore than 10* BTDC with my engine otherwise the starter gets drug down on hot restarts. Other than the smoother idle in the cold I can't tell a difference otherwise. I've never done a hot compression test with the current XE250H cam but the old what seemed to be a 252H produced 150-155 PSI cold, with my old smog heads. It must have pretty high cranking compression, should test it some day. My current timing setup is 10* BTDC, 26* centrifugal advance for 36* total all in by around 3100. I still get pinging occasionally, but not often. Might back it off a couple degrees and see if the occasional pinging goes away.
Iv had a lot of success with more initial mechanical, ported (so there isn’t too much idle timing), then limiting my total timing to 34-38 degrees. It’s not about ported vs manifold - it absolutely wants more timing, you just have to provide mechanical initial. Then your carb settings transitionally are not also way off base.
@@ThunderHead289 I've played with the springs in the past and tried it all in by 2600 RPM and it ran real good but pinged a lot. I think the truck weighs too much and the camshaft is a bit on the tight side as far as overlap and not bleeding off cranking compression goes. Most any other engine I've tuned set it 12-16* BTDC with no vacuum advance at idle and the timing all in by 2500-2800 depending and they ran great with no hot restart issues from timing being set too advanced. Not sure what the deal with this one is. If I set my timing to 12* BTDC or higher, the engine almost won't crank over when it's hot. Set it to 10* or less and it whizzes right up. The engine loves a lot of timing as far as running goes but it creates other issues. Ugh lol.
Why do you set the timing in drive and not in park when you have an automatic transmission? If you have an automatic transmission do you hook up the ported vacuum back to the distributer and then set the timing in drive? Thanks
The only difference between manifold and ported vacuum is at idle. Has nothing to do with base timing. Manifold gives full vacuum at idle and usually provides a bump in RPM (need to readjust idle) and vacuum. The engine runs cooler and more efficient with manifold vacuum at idle. As soon as you crack the throttle vacuum drops to exactly what it would be with ported vacuum. Hence they are the same timing wise and both add too base timing exactly the same amount (if at all, full throttle) once throttle is applied. With that said, love your videos.
Scott Newman it’s all good - Iv been told a million times I’m too wordy and he’s to listen to - there was a time when I was a better presenter. Now I guess I have too much to say
If you use a vacuum advance, (which is pretty much only there for part throttle ECONOMY), hook it up AFTER you have set the total timing. Of course when you are driving down the highway at PART throttle, the vacuum advance will pull anywhere from 10 to 15 degrees MORE advance (beyond your total timing) BUT under HARD acceleration, the vacuum advance DOES NOT WORK anyway, so you're back on your total timing when you're ON the throttle. Personally, I almost never use a vacuum advance on performance engines, A vacuum advance can also be used to help engines get rid of "Run-on" or "Dieseling" problems when you shut the engine off. But! you can also do this by hooking it up to a MANIFOLD vacuum source to pull more advance when the engine is idling. The reason for doing this is to make that extra timing being pulled at an IDLE to increase the idle RPM, which in turn allows you to back-off on the idle speed screw, which in turn closes-off the throttle plates! .....So when you shut the engine off, it can not "mechanically" continue to pull fuel and air into the engine causing it to Diesel. Hope I haven't confused you Scott.
i hav tried both .found my set up liks 20* at idel. my dizzy has 20* cetrifical advanc all in at 3700 rpm. so using 20* base would give me 40* total too much for sbf in a truck! it has a auto trans and hi way gears so it will not like agresive timing off idel. i use 87 octan as it is a 8.7:1 smoger with a lean jeted 2150 so have to be consrvitve timing with noegr. i us 2* base 18* vacuum advanc for 20* at idel ,22* at wot,40* at cruse 2+18+20centrifical=40. ported vac will restict you to using low base timing to stop ping. then you get a crapy idel and it will run hot do to the fuel burn being slow! also with ported vac from the late 60s+ moust used a temp swich to swich to manifold vac to cool the engine if it got to over 200*! so i use manifold vac!
If you mash the throttle with only two degrees of initial it’s going to be a DOG. You lose all your vacuum advance timing as soon as you leave from a stop until your speed stabilizes. While accelerating you are absolutely on mechanical only. Here is the solution to your problem - stop bushings - or some kind of advance limiter. This is why msd distributors use stop bushings to allow you to run the mechanical initial you need while still maintaining effective total. Does this make sense? 15 degrees of vacuum advance is the very reason ported should be utilized - that’s way too much vacuum timing at idle - handling a timing transition off idle of 15 degrees is dang near impossible to balance out - you will always have a hiccup, or in an auto, a flat spot!
i get what you are saying i need to limit the mechanical so i can use more base time. but 20 is a lot of base time, bet it wold ping off idel with 87octan with c4 and 2:80 rear gears in a truck! that is why i use manifold vacuum and 2* base time. but it wold be a neat to try that much base but i bet it wold not like to start hot! all so most sbfs like around 22-24* total with a auto with regular gas just look at the fox body timing tables for a auto. IT runs well no bog. i notice no difference in take off. i have ran as much as 12* base and ported vacuum 32* total with 12* vac advance. I try both on all my engines and find manifold works for me most the time. and ford has even used manifold vacuum! most ported setups form late 60s used a temp switch to switch to manifold to cool the engine ! i do understand that ported can work but all engines are different and think manifold is right for me using 87 octane in with tall gears and auto in truck will need the timing to drop to avoid ping. well love the stuff you do take care and carbs rule!
My question is if you set your secondaries slightly open like I saw you do in another vid will that #1 give you a reading on your vacuum gauge at idle? #2 reduce your total vacuum when trying to set to highest vacuum idle with mixture screws?
Do better(mild) cams in a chevy 350 need different vacuum? I ask because I've built a 350 with an elgin e921p cam. I've got idle tuned pretty good with great throttle response but at idle in gear it runs much more smooth when vacuum advance is on manifold vacuum using edelbrock avs2. Are these directions mainly for stock engines? Do you have videos on upgraded cam timing?
Just bought my 1st car it's a 70 ford fairlane 500. Also my 1st dive into carburetors haha. Quick question. Engines a 302 and the gas pedal is a little hard to push down. Any idea what that could be? Or are older V8s just like that?
Any performance motor I’ve built and using the stock Dizzy I’ll only use the mechanical advance and not use the vacuum. I get as much initial timing as possible and then recurve the mechanical advance if needed to get my total timing! Typically vacuum advance is for fuel mileage
Your engine is late at cruising throttle angles if your vacuum advance isn't hooked up. Cylinder pressure changes based on throttle angle - an engine is nothing but an air pump where the throttle is a restriction. Atmospheric pressure is trying to cram its way in there, but the throttle restricts it where you have a less dense cylinder charge. A less dense charge burns slower - ie you need to ignite the mixture sooner for flame propagation to happen at the right time in the stroke. Not running vacuum advance is just silly on a car on the street. Thunderhead289 - engineer.
@@ThunderHead289 I should restate what I said ….I usually don’t run vacuum advance on engines with more than 220 degrees of duration @ .050. I run as much advance as possible like 16 -20 degrees base timing or more if the starter will do it…then mechanical advance will have 15-20 more ….all in between 2500 - 2800? Throttle response is amazing as well as over all driveabilty ….vacuum advance at this point is redundant. Granted I mostly work with fords which most ford combustion chambers are not a fast burn chamber so many times 36-40 degrees total timing is needed ….. Not bragging but in my town most every gear head knows me as the Fast Ford guy!
@@ThunderHead289 Also a vacuum advance will only advance on ported vacuum once the engine isn’t under heavy load.. Like when you have your foot into the throttle even half way the vacuum advance isn’t doing much! Only around cruise speeds is where the vacuum advance works the best….when you floor it , vacuum advance does nothing for a curve! Vacuum advance to me isn’t very consistent either!
I should also add I enjoy your break downs of operations with carbs , timing and engine operations as such! Spot on and informative more than any other channel I watch! For a stock engine I agree with using the vacuum advance but some old lean burn engines and others ran better without the vacuum advance hooked up! In my experience it really depends on the motor design, compression ratio amongst 50 other factors involved.. As with carburetors they rely on the basic function of an engine being in good shape ….on a tired old motor you can really play with timing curves to make it run as good as possible ….sometimes eliminating the vacuum advance simply advance base and adjust total timing accordingly…
Need help !!! 64 Belair, summit 600... changed the intake and carb to the Summit 600, as soon as I fire it up the idle screams up, idle screw is adjusted all the way out
That’s annoying - I’d see how much timing you can run in it without it acting odd. If you have to astranomically close your curb idle screw and lean your mix screws, it’s too much timing. Depending on how much timing your advance canister pulls, you might be able to get away with mid 20s for timing
Initial Idle screw/transfer slot adjustment? Does Holley/Summit or Edelbrock (or other Carburetor manufacturers) provide a number of turns for the initial idle screw setting that will get us in "the ball park" for a good initial transfer slot/throttle plate relationship without removing the carb?
I rebuilt my holley but it still seems like there's a fueling issue almost like it's not always delivering enough but other times it is. I'm not real familiar with how they work so I'm curious as to how the carb still pulls fuel when it's idling and where the fuel comes out of and goes into the manifold. I know it doesn't come out of the squirters until you give it throttle so where does the fuel come from when idling. It's a 600 cfm
Trey Lewis lmao good luck I was gonna go with a 383 but I was like I’d be filling up every other day with that lol I ended up getting a 350 making 387 hp and 417 torque I’m happy with it
I'd like to hear your opinion (if you have experience with) the initial timing on a Ford with efi & the EEC IV. Base timing is 10* Do you think it would be beneficial to set it at 12-13? My concern is that the ecm will have the timing over advanced at wot
Nice video 👍A newbie question but if I don't ask I won't know, I have an Edelbrock 650 carb and bought an MSD pro distributor, would I still benefit from using this option? Thank you for any suggestions.
Absolutely! Also, run one of the lightest spring and one of the middle of the road springs. Add the proper stop bushings for 32-36 degrees of total timing after you set initial
Great, now I can't stop dropping "myriad" into every conversation, LOL. Other than that, thanks for the carb setup tips, your vids are the best out there!
Crockett85 - on the ported connection, there is no vacuum registered at the port. There is vacuum in the intake, it is just not passed to the port. Thus, with a gauge hooked to the ported port, it will read zero. Then when you open the throttle a bit, the port gets exposed to manifold vacuum, so it then registers. It appears that the vacuum goes up, but this is just at the port. If you were measuring the vacuum on the full-manifold port, the vacuum actually drops when the car’s RPMs go up from idle.
ThunderHead289 Wouldn’t too much base advance on a fuel like 87 cause detonation? If you tune timing based on ported vacuum, and then based on idle speed, how does this guarantee the best performance based on the fuel you chose? If you put race gas in your truck, you would be more concerned with total advance, but initial is important too right? I’m just trying to advance my car’s timing for performance.
I have a supercharged sbc 350 with a 671 it is running lean 18 to 20 with the aem afr gauge but burns my eyes like it's too rich why would the gauge read like its lean
A common misconception about lean is that it doesn’t have a smell - when a fuel charge isn’t properly burning due to timing or an out of spectrum ratio, you will smell it. Contrary to popular belief, lean reeks too! If you want to cross reference, review your plugs!!!
Well the supercharger adds another bit of complexity where it’s simplified by locking timing although not ideal. Give the units a look I linked and review it’s function - they are what I’m going to run on my supercharged engine.
No. Usually the vacuum port furthest from the cap is the advance. That second port is part of some smog/EPA/gas crunch setup. Depending on which car it was, sometimes those ran through a temperature controlled vacuum tree which opened and closed the vacuum source based on how warm the engine was. In some examples, the automakers intentionally de-tuned engines when they were cold or at idle. Making the timing run late while the engine was idling caused the engine to start exhausting while the gas charge was still burning. Ford got similar effects to having a catalytic converted back in '73 like that. It made the engine run hotter and more heat under the hood coming off the exhaust system. They had to pass stricter emissions controls and did so at the cost of running the engine and exhaust manifolds a lot hotter. Sometimes the manufacturers used similar tricks just to help the engine warm up to operating temperature faster. Anyways, if you're here and watching this video, then probably you aren't worried about this smog and emissions stuff. You're here for horsepower and drivability. Cap off the vacuum port on the distributor closest to the cap. Then connect the other port to whatever vacuum source makes you happy, and tune away.
@@reidbarnes9851 By 74, ford was in full swing with all sorts of crazy thermal controlled vacuum stuff for emissions. If your engine still has most of that equipment still hooked up, I would suggest getting a feel for what everything is before you start taking parts off and plugging ports. :D I think the subject matter and the advice in this video kind of assume all that silly emissions and smog stuff is gone anyways. There are some points like making sure your transfer slots in the carb are properly adjusted that do apply. But then any advice dealing with timing and vacuum, it feels like a fool's errand to try and tune your engine for horsepower and throttle response while still having to work around and fight those systems that intentionally de-tune the motor at idle.
@@giantpune most of the smog equipment was gone by the time I got the truck. I deleted some more of it. The vacuum advance that was on it wasn't working but only had the one port. The new replacement one had two ports.
I have a spot on my edelbrock 1405 that while im driving about 15mph, and i punch it, it will dog out. I cant tell if its not enough fuel or too much fuel. Otherwise everything else runs good on it. It seems fine when launching from a stop Just a flat spot when im already crusing and punch it. at start of power valve or such? I dont know what to do without a wideband O2 sensor to tell if its lean or rich when this happens I am using manifold vaccum and a while ago i set the fuel squirt to the largest squirt since it seemed like at the time it was dogging out during launch from stop. But now maybe its too much fuel during a punch at cruise? Its a 1979 ford f350 with a 460 engine, stock intake, 8 degrees stock initial timing Ill try your tips out to see if it improves
What is your timing set to at idle, and what is your overall timing setup? Like I mention in this video, timing is everything. Fueling and timing has a dynamic relationship, so they both play off of each other
@@ThunderHead289i am using manifold vac advance, and i have it set to 8 degrees before attaching vacuum. I dont recall the degrees once i hook up the manifold vac..i will have to check that again. Probably like 30 maybe, but i dont recall. Thanks for the tips i will try port vac again soon and see if that helps overall. The 8 degrees is because that is the factory recommended setting on tje valve cover lol. But thats probably also when you have all the emissions hoses , which i no longer do
If you set the engine up on the principles I do in this video, you will smile when you hit the throttle. It will probably ask for less accelerator pump also
Research and Build from the factory smog pumps, retarded cam timing timing chains, and ignition timing retard canisters were used also - the factory has to manufacture things to meet certain specifications. Also, factory tunes are painfully safe. YOU do not have to play by the same rules.
I dont like asking for advice but here we go i have a sb chevy with msd hei 9.71 com summit 600 vac second summit dull plain int comp little thumper cam 3in duel ex with summit bullet mufflers 700r4 trans stock converter.now in comp cam ad they say stock converter will work fine but im haveing idle problems.i put 34 degre total adv any more it spark knoks with 92 octaine and it has headers.with that being said at idle in gear i have about 2 deg of timming with vac adv at ported vac idl like shit.and yes i checked transfer slots there good.now do you think the coverter mite be the problem draging the engine down to much or do i need to look at doing something with hei.i really think i dont have enough initial timing but as you can see i cant put more timing in or it spark knoks help im at a loss any sug would be great.keep up the great videos there very helpfull.
What is your full initial timing? I guess I didn't exactly understand your comment about your initial timing. But that's the downfall of the hei, it's hard to limit total timing - there is a simple method that I'd be happy to show you, I just can't via TH-cam - find my on Facebook, search thunderhead289 and send me a message
The manufacturers specifications were guided by corporate bean counters, government regulations, them having to warranty and service cars, etc. Carol Shelby and his crew were not out at the race track reading numbers out of the ford shop manual to milk as much horsepower as they could from his car.
Bobbie and Ian Guenter when you switched to ported did you advance your initial mechanical timing tho.... The responses to this video disappoint me - I must be hard to listen to. This is not a video about manifold vs ported.
@@ThunderHead289 I enjoy all your videos and am sorry I sounded negative. My problem was limiting the advance on my Hei when I bumped up the initial timing. I took the easy way and used manifold vacuum.
This comment is a great example of why some people might never catch on to fixing their own stuff. You have to be willing to dig into problems yourself and narrow down possibilities by deductive reasoning & patience. That's the best way to learn. In this case if you would have tried watching other videos you would have discovered by yourself the lack of sound issue was on your end.
I' m not paid to say this - its rare for me to endorser anyone or anything. - it takes something special.
ABSOLUTELY check these guys out!!! Brand new company, with the coolest thing I have seen in the auto market since the 5 speed swap!!! progressionignition.com/
nice
Dangit they dont seem to have ford 460 models
Research and Build yes they do it’s the same model as the 351C
Sadly, I couldn't find one for my 84 2.8L V6 171
About 5 years ago you did a video that gave the complete opposite info. You where all about running manifold vacuum advance.
My daily driver is a 72 f250 , all your videos are so helpful in making my Holley run smoooooth .... down these Phoenix roads ... always looking forward to them . Keep up the great work ...
Thanks so much!
If a wore out tired old 181k mike 390 can pull hard, anything can.
Timing is the single most misunderstood and neglected tuning item of all time!!! It makes a massive difference!
I've always used a vacuum gauge when setting initial timing. Like you I plug it into the ported port and advance it until I get the highest vacuum then back it off slightly and lock it down, bob's your uncle. Always ran beautiful.
Luke. I’m sending out a personal “Thank you”.
I’ve watched many of your videos on timing and carb adjustments and taken that to my carbureted marine 454.
I install a fuel pressure regulator with a return line, squared my transfer slots (edelbrock 750) and adjusted my timing to get my idle set right. The thing starts amazing now. Runs absolutely PERFECT and gained about 2 mph on the top end.
👍👍👍👍
It is refreshing to see a somewhat younger technician with such an understanding of old school technologies and how they relate to one another, as well as being able to explain it simply and completely.
Ironically im an automation engineer/programmer by day - so figure that one
Always thankfull for your videos, spreading the knowledge is gonna keep our old cars on the road and off the junkyards, and therefore helping our analog car culture to stay alive.. Thank you 👍
Hi Luke. I am running a holley 600 DP. On a stroker 331. My ported port is blocked off with a flush Ailen screw. I am trying to locate a screw in vacuum nipple where can I locate one have a suggestions Guido 👍🏼
This Man should b 2020 hot rodder of the Year, shows all this for Free advice and goes out of his way to Help everyone........got my Vote
by watching your videos, u helped me set up the carb on my truck.
I daily a 1984 Ford Ranger. Your videos (Despite you dont have much motorcraft carb videos) taught me a lot on getting my engine to run right! I plan on doing a engine rebuild soon!
Motorcraft carbs are generally equivalent to holley carbs. Holley made Motorcraft carbs since the 50s
thank you,,,,,,for your generous time.........I'm fortunate to watch your video seminars , you relay the information like a professional university teacher......I've studied many books and have a hard time relaying to others what I have learned...You sir have a great intellect and talent...............I'm a Drag Racer....I've been studying articles, and books since 1965 , as I am 69 years young.............TL
Thank you, your videos are QUITE useful. We bought a 1955 Thunderbird that has a 1957 312 installed in it. Used your video about adjusting clutches to fix the issue with our's. It was NOT adjusted at all since the clutch had been installed years ago. Our car has a Holley 1848 just like your truck and has a Mallory Unilite distributor in it that has no vacuum advance. According to the tach it idles at 1400 rpm's and still needs the clutch feathered a bit on the off in first to avoid stalling. Manifold vacuum measured at the manifold is 17.
He’s right. 100%. And setting it up correct is the difference between a killer launch and one that doesn’t come on at all until you hit 2500 rpm.
Just wanted to throw out a big thanks to you ! I have my 79 302 equipped 2wd in the garage & it’s never really ran the greatest since a rebuild I’m positive with some proper tuning it’ll purr again soon
This is great! I can't tell you how many people I've asked about the abrupt loss of advance when plugged into manifold vacuum. This all makes perfect sense and I can't wait to try it out after my engine is back together!
I just had a cam and lifters put in my 400. I couldn't get it to idle right for anything! I watched your videos on ignition timing and the Edelbrock tips in this vid, since I'm running a 600cfm Eddie. Your advice has this thing idling correctly, and it pulls smooth with no hesitation at all. I owe you a venison dinner!!
Let me start by saying i think youre a super intelligent guy who knows what hes doing and does a good job getting information across. I do want to follow it with saying i completely disagree with you about ported / manifold vacuum. The best way ive found is set up like you say, neutral for manual, gear for auto, vacuum gauge on manifold vacuum, vacuum advance unhooked. Increase static / base timing until you find the highest vacuum point (adjust rpm back to spec as needed). THAT number is where the engine is most efficient and that number is what your idle timing should be. Generally this number is anywhere from high teens to low 30s depending on cam, compression, and altitude. Now, we all know that very few engines are going to start with 28* of initial timing, and even if they did as soon as you put a load on it its going to ping like crazy. So lets set our base timing back to something reasonable, generally speaking, camshaft duration and overlap is going to dictate this number for us (theres charts on the interwebs). In the case of my cam, 18* works pretty well, then to that, we add our vacuum advance, which in my case is ~14* for a total idle timing of 32*. This is why manifold vacuum is superior. You say that manifold vacuum retards timing as soon as you crack the throttle, it does, but it never going to be lower than it was on ported. You have all the advantages of the engine having the timing it wants at idle, with none of the disadvantages, snappy throttle, cooler idle, quieter, etc. It is especially useful for engine with large cams that have a hard time reaching an acceptable idle without over exposing the transition, opening the secondaries, or drilling bypass holes. Ported vacuum exsists because of CARB and the EPA, retarding the timing at idle increases idle exhaust temperature which cuts down on hydrocarbons, warms the engine up faster, and produces less NOX. I will get off the soapbox but i will add that not all engine should necessarily run manifold vacuum. Stock engines generally dont benefit as much because there is less benefit to be had. In the case of a daily driver for instance, the faster warmups are nice, but for performance, after having tried both multiple times, there is only one answer, and it isnt ported.
A quick story on ignition timing and advance curves. When I first assembled a Pontiac 455 years ago it seemed sluggish off idle and didn't have the torque I was expecting... until one day I took off from a stop light and at about 20 mph it lit the rear tires and felt like a 150 shot of nitrous. It turned out that the mechanical advance weights in the new distributor had been sticking and finally let loose. I hadn't checked the curve, figuring that a new distributor would be functioning properly. Lesson learned.
Might be a stretch! It would be awesome if you did a video series on a A-Z engine rebuild. Like what to do, how to do it, average cost of the rebuild kits and what you NEED to replace, and the cost of getting the machine work done, Finally. Putting it all together, setting the timing, getting the engine in the truck or car with the carb all setup and running right. Id like to see something like that! Especially from you! Since you've got a lot of knowledge on that subject!
Your videos helped me get my 65 Thunderbird back running. Learned a lot about carbs but still know nothing about different sized jets! Video idea?
Nice! Those autolite carbs are great carburetors when they're set up properly. Have fun with that 390!
All that knowledge and you have the skills to break it down so a dummy like me can understand it, good work man and thank you
Thanks so much
I’ve been arguing the timed port thing since the 80s with my buddies. You’re doing the hobby a lot of good . I always look forward to seeing your videos!!
Thanks so much! There’s a false belief out there that it’s associated with emissions. My 64 galaxie is factory ported with no PVC or anything else smog. I highly doubt that the ported port was an attempt at smog control in 64!
Even if it is, it can be utilized to get the correct mechanical timing on an engine! A lot of stock timing curves are lazy!
I had a friend who started building engines when he was like 10. My foundation for engine building and tuning came from him. Using ported vacuum was the first thing he stressed about setting idle and tuning carbs.
That's cool he made a distributor modual to control with your phone timing and other things on old carb systems
Man, it’s extremely cool - meeting the guy made it all the better
“I was pissed I couldn’t do exactly what I wanted, so I made something that gave me the ability to”
Straight badass
Great info. I think these are the reasons so many people are switching to EFI for their builds. Just slap them on and drive.
Saw you were driving down lincoln way, I work around there. Going to try this on my 72 chevy k20 with a 454. Thanks bud!
Dam that Progression Ignition unit is slick! I need to get one for the LeMans
Ah yeah, we will have to get one mate
@@ThunderHead289 a bloody genious
Thanks for sharing the information. I'm currently working on a 76 f150 (360) dealing with egr and vaccum stuffages. I may pull the carb off again after watching several of your vids and double checking the transition slots. I had vaccum at idle apparently at the egr port. Still working on adjusting things to get it running better, for a 2bbl, eventually going to turn it into a 445 stroker. Still appear to have egr issues, but I will deal with that later. I also put in a digital dash it is a great addition and I like the way it looks and gives me more information on what the engine is doing. I noticed in one of your other vids you have a af guage. Do you have the stock exhaust with it tapped into the pipe where they meet or are you running dual exhaust and just have one pipe tapped?
Great tips thunderhead and tricks good informative demonstration
Very helpful and informative video, I definitely appreciate the time effort and patience that you put into these video guides. Your truck deffently has a very nice sound exhaust!!
Gonna try this myself as well. Thanks for this vid and the clear explanation. 🇨🇦👍🏼
Oh! I always ran 10 degrees initial and the manifold vacuum to the HEI with what ever it came with. Then promptly fiddled with the carb settings. No wonder it was never a good feel. I really enjoyed the Engine Masters episode about total timing, really got me to thinking. Your episode really got me to thinking about the transition. What about a performance cam with questionable idle vacuum? Still the same principle?
A high lift cam will have less cylinder pressure at idle, which will require more timing!
Usually those land at 16-18 degrees advance.
Just some background understanding, the overlap at low engine speed bleeds off compression - less compression means a slower burn time which calls for more timing to burn the mixture at the right time in the stroke!!!
Conversely, what they give up down low they provide up top! The Overlap creates a scavenging effect which draws the next cylinder charge in at higher rpm where a lower rpm cam will run out of breath!
@@ThunderHead289 oh, oh! I see now. I've just never had enough initial timing and was hooked up to manifold vacuum on the distributor. No wonder it's crap on tip-in. I cruched the problem with faster idle, wondering why the mixture screws weren't responding. Too mucho transfer sloto! 😬 I feel better now watching your tuning series that I can start at square one and dial the setup in. Thanks!
@@ThunderHead289 in that situation, would you dial in quite a bit of initial advance, and then limit how much total with stop bushings? I have a 10:1 302 with Bennett Racing ported heads and a 230/240@.050 camshaft. Edelbrock Performer RPM and 650 mechanical secondary in my 1964 Fairlane. Only makes 8-10 inches of vacuum at idle. Sounds like my best bet is to square the transfer slots, and use timing to get the idle where I want, then limit mechanical advance until I total at 34 degrees or so? I already have to run the Holley throttle plates with .093 holes on the primaries.
I always use ported vacuum for timing. My brother always used manifold vacuum and mine always performed better off idle.
Hey Luke, great job with the videos - very informative and teaching to anyone even remotely interested in old school tech and cars.
A question - Got my grandpa's old Fiat from 1964 that I've slowly been building for a couple of years and in a week or so it's at the point of starting up after I get the fuel lines done. Any tips on what last minute things to do before I crank it? The last time it ran was back in 2012, at that time it started after 1 minute of cranking with old oil and having just sat for 25 years. The car's been sitting in a warm garage for the last 45 years. Oil / fluids? Anything else? There's still some 70's fuel in the tank lol
@ThunderHead289
I'm so glad you make these videos. Not everyone wants to drive their classic like a freakin race car! I really appreciate what you say about timing and ported vacuum. I'll bet you if you examine the shop manuals of countless classics for the initial setup of ignition and carburetor systems, ported vacuum will always be hooked up to the advance mechanism of the distributor. Those engineers didn't know everything, but they weren't stupid either.
Just as long as a guy advances his initial timing, all will be well. Obviously an engine that requires notable advance will fare better with a distributor recurve to compliment this improvement
Man I always do it in park or neutral on my galant... gonna try
Been running manifold vacuum on my 73 f250 highboy just because that's the way the 2 barrel was set up on it when I got it, now it has a AFV elderbrock 650, I will try this , something to do during lock down
Have fun my friend 👍
Just be sure to advance the initial mechanical to compensate
@@ThunderHead289 dura spark distributor with MSD ignition, lighter springs in dist, thanx for videos, very informative
Thanx luke, did the changes and it pulls the hills around here much better and better off the line acceleration, FE 390
Great video! Thanks for showing this. Just a question. What MPG are you getting on that FE now that it is dialed in?
To put it in perspective -
I tried it both ways for fun, I’ve gotten a whole one way trip to work better in a week.
Which is notable since I live 40 minutes from where I work!!!
ThunderHead289 that is excellent!
I know that can be the stupidest ask but is the horns of the truck working I mean the clacson? I'm asking that because I collect classic clacsons and fix them. I saw four of them on the truck two air horns and two electric I don't know why this truck have four horns if it's needing only two or may two of them aren't working. So are they working?
I always use manifold vaccum, I’m gonna try this.
Kind of wish this was out 3 years ago before I got fed up with carbs and last swapped my truck lmao.
Did you mean fast?
@@ThunderHead289 sorry, meant Ls swapped haha
Hey Mate...Can I assume you got your 14 degrees timing sorted whilst the vacuum line was connected back on the ported vacuum between the distributor vacuum advance? OR did you adjust your timing and idle whilst they where NOT connected? ( and plugged the holes) It would also be good to show the viewers how you connected the vacuum gauge (to see RPM) During your Timing Adjustments....for those who don't know how... just my two cents.. Good video!
How can I set slots without carb being off? Is there a round about curb idle screw setting to start with? Thanks for the 411 vid.
I need to get a vacuum guage now...thanks!
I’m probably asking a dumb question but I’m a little unclear on adjusting the transfer slots. Are you saying to just do the dance between your idle speed, idle mixture, and timing and that if you do all that and aren’t pulling vacuum at idle off the ported port, then you should be set correctly as far as the slots? So if I get set and have a little vacuum, I should back off my idle speed screw and give a little more timing?
Hello, we just bought a Vanguard R.V. with the 1986 Ford E-350, 460 3 speed. Do you recommend removing all the EGR components and plugging the exhaust manifolds? There's no cat in it. If so, tuning afterwards would make sense, right? And there's a lot of potential problems with ICM, where some have a spare one on hand, much cheaper than buying a MSD or Progression Distributor. But if we put in a Progression distributor than would we have the need to buy a timing light and other gauges? Definitely the vacuum gauge. But a timing light also would be cheaper than a new Progression distributor. So, what gauges to you recommend for the interior, for the minimalist. ;-) Thank-you.
I have a 32' Ford PU with a 51' Merc. 255ci engine in it. Is there anyway I can apply your video to it? Stock is 7.5 to 8.5 deg. @ 2000rpm. I am running the stock Holly "tea pot" carb. and don't want to change. A dist. rebuilder recommends 18deg. @ 2500, mine will ping at that setting. Should I do "old school" and adv. until it pings, then back up a deg. or 2. These dist. are unusual as to where they take the vacuum from. You cannot run multi. carbs with a stock dist. Have watched 4 or 5 of your videos, VERY informative and to the point. Thanks frank
My car a 1962 Chevy with Carter afb does not have a ported vacuum port. The only vacuum port is direct manifold.
Ok ill try it, i dont remeber why i set mine the way i did. Ive all way set the timing but ear, then made it idle with a flat head. Three things no shakey, slow, and not smell like gas, then it idles nice...
You are super awesome guy. thanks for the video ✌️👌👍🧢
Is the vacuum gauge hooked up to the carburetor or the manifold?
All is good, ported vacuum how many guys argue about that. I done about the same with vacuum gauge to prove the point. But get rid of the plastic fuel filter.. lol 😆
I've run both ported and manifold vacuum advance and for my application I chose manifold vacuum for vacuum advance. Mostly because it idles much better in the cold with more timing once the choke comes off. I can't run anymore than 10* BTDC with my engine otherwise the starter gets drug down on hot restarts. Other than the smoother idle in the cold I can't tell a difference otherwise. I've never done a hot compression test with the current XE250H cam but the old what seemed to be a 252H produced 150-155 PSI cold, with my old smog heads. It must have pretty high cranking compression, should test it some day. My current timing setup is 10* BTDC, 26* centrifugal advance for 36* total all in by around 3100. I still get pinging occasionally, but not often. Might back it off a couple degrees and see if the occasional pinging goes away.
Iv had a lot of success with more initial mechanical, ported (so there isn’t too much idle timing), then limiting my total timing to 34-38 degrees.
It’s not about ported vs manifold - it absolutely wants more timing, you just have to provide mechanical initial. Then your carb settings transitionally are not also way off base.
@@ThunderHead289 I've played with the springs in the past and tried it all in by 2600 RPM and it ran real good but pinged a lot. I think the truck weighs too much and the camshaft is a bit on the tight side as far as overlap and not bleeding off cranking compression goes. Most any other engine I've tuned set it 12-16* BTDC with no vacuum advance at idle and the timing all in by 2500-2800 depending and they ran great with no hot restart issues from timing being set too advanced. Not sure what the deal with this one is. If I set my timing to 12* BTDC or higher, the engine almost won't crank over when it's hot. Set it to 10* or less and it whizzes right up. The engine loves a lot of timing as far as running goes but it creates other issues. Ugh lol.
Why do you set the timing in drive and not in park when you have an automatic transmission? If you have an automatic transmission do you hook up the ported vacuum back to the distributer and then set the timing in drive? Thanks
The only difference between manifold and ported vacuum is at idle. Has nothing to do with base timing. Manifold gives full vacuum at idle and usually provides a bump in RPM (need to readjust idle) and vacuum. The engine runs cooler and more efficient with manifold vacuum at idle. As soon as you crack the throttle vacuum drops to exactly what it would be with ported vacuum. Hence they are the same timing wise and both add too base timing exactly the same amount (if at all, full throttle) once throttle is applied. With that said, love your videos.
You clearly didn’t listen to a word I said.
I discuss what you say in your comment.
@@ThunderHead289 Your right. I watched it again. The wife must have distracted me or something. Anyway. Love your videos.
Scott Newman it’s all good - Iv been told a million times I’m too wordy and he’s to listen to - there was a time when I was a better presenter. Now I guess I have too much to say
If you use a vacuum advance, (which is pretty much only there for part throttle ECONOMY), hook it up AFTER you have set the total timing.
Of course when you are driving down the highway at PART throttle, the vacuum advance will pull anywhere from 10 to 15 degrees MORE advance (beyond your total timing)
BUT under HARD acceleration, the vacuum advance DOES NOT WORK anyway, so you're back on your total timing when you're ON the throttle.
Personally, I almost never use a vacuum advance on performance engines,
A vacuum advance can also be used to help engines get rid of "Run-on" or "Dieseling" problems when you shut the engine off.
But! you can also do this by hooking it up to a MANIFOLD vacuum source to pull more advance when the engine is idling.
The reason for doing this is to make that extra timing being pulled at an IDLE to increase the idle RPM, which in turn allows you to back-off on the idle speed screw, which in turn closes-off the throttle plates!
.....So when you shut the engine off, it can not "mechanically" continue to pull fuel and air into the engine causing it to Diesel.
Hope I haven't confused you Scott.
i hav tried both .found my set up liks 20* at idel. my dizzy has 20* cetrifical advanc all in at 3700 rpm. so using 20* base would give me 40* total too much for sbf in a truck! it has a auto trans and hi way gears so it will not like agresive timing off idel. i use 87 octan as it is a 8.7:1 smoger with a lean jeted 2150 so have to be consrvitve timing with noegr. i us 2* base 18* vacuum advanc for 20* at idel ,22* at wot,40* at cruse 2+18+20centrifical=40. ported vac will restict you to using low base timing to stop ping. then you get a crapy idel and it will run hot do to the fuel burn being slow! also with ported vac from the late 60s+ moust used a temp swich to swich to manifold vac to cool the engine if it got to over 200*! so i use manifold vac!
If you mash the throttle with only two degrees of initial it’s going to be a DOG.
You lose all your vacuum advance timing as soon as you leave from a stop until your speed stabilizes. While accelerating you are absolutely on mechanical only.
Here is the solution to your problem - stop bushings - or some kind of advance limiter.
This is why msd distributors use stop bushings to allow you to run the mechanical initial you need while still maintaining effective total.
Does this make sense?
15 degrees of vacuum advance is the very reason ported should be utilized - that’s way too much vacuum timing at idle - handling a timing transition off idle of 15 degrees is dang near impossible to balance out - you will always have a hiccup, or in an auto, a flat spot!
i get what you are saying i need to limit the mechanical so i can use more base time. but 20 is a lot of base time, bet it wold ping off idel with 87octan with c4 and 2:80 rear gears in a truck! that is why i use manifold vacuum and 2* base time. but it wold be a neat to try that much base but i bet it wold not like to start hot! all so most sbfs like around 22-24* total with a auto with regular gas just look at the fox body timing tables for a auto. IT runs well no bog. i notice no difference in take off. i have ran as much as 12* base and ported vacuum 32* total with 12* vac advance. I try both on all my engines and find manifold works for me most the time. and ford has even used manifold vacuum! most ported setups form late 60s used a temp switch to switch to manifold to cool the engine ! i do understand that ported can work but all engines are different and think manifold is right for me using 87 octane in with tall gears and auto in truck will need the timing to drop to avoid ping. well love the stuff you do take care and carbs rule!
I think so many people are against ported vacuum, is b/c a stock dizzy needs to be recurved to operated correctly with port vac.
My question is if you set your secondaries slightly open like I saw you do in another vid will that #1 give you a reading on your vacuum gauge at idle? #2 reduce your total vacuum when trying to set to highest vacuum idle with mixture screws?
Do better(mild) cams in a chevy 350 need different vacuum? I ask because I've built a 350 with an elgin e921p cam. I've got idle tuned pretty good with great throttle response but at idle in gear it runs much more smooth when vacuum advance is on manifold vacuum using edelbrock avs2. Are these directions mainly for stock engines? Do you have videos on upgraded cam timing?
Just bought my 1st car it's a 70 ford fairlane 500. Also my 1st dive into carburetors haha. Quick question. Engines a 302 and the gas pedal is a little hard to push down. Any idea what that could be? Or are older V8s just like that?
Any performance motor I’ve built and using the stock Dizzy I’ll only use the mechanical advance and not use the vacuum.
I get as much initial timing as possible and then recurve the mechanical advance if needed to get my total timing!
Typically vacuum advance is for fuel mileage
Your engine is late at cruising throttle angles if your vacuum advance isn't hooked up. Cylinder pressure changes based on throttle angle - an engine is nothing but an air pump where the throttle is a restriction. Atmospheric pressure is trying to cram its way in there, but the throttle restricts it where you have a less dense cylinder charge. A less dense charge burns slower - ie you need to ignite the mixture sooner for flame propagation to happen at the right time in the stroke.
Not running vacuum advance is just silly on a car on the street.
Thunderhead289 - engineer.
@@ThunderHead289 I should restate what I said ….I usually don’t run vacuum advance on engines with more than 220 degrees of duration @ .050.
I run as much advance as possible like 16 -20 degrees base timing or more if the starter will do it…then mechanical advance will have 15-20 more ….all in between 2500 - 2800?
Throttle response is amazing as well as over all driveabilty ….vacuum advance at this point is redundant. Granted I mostly work with fords which most ford combustion chambers are not a fast burn chamber so many times 36-40 degrees total timing is needed …..
Not bragging but in my town most every gear head knows me as the Fast Ford guy!
@@ThunderHead289 Also a vacuum advance will only advance on ported vacuum once the engine isn’t under heavy load..
Like when you have your foot into the throttle even half way the vacuum advance isn’t doing much! Only around cruise speeds is where the vacuum advance works the best….when you floor it , vacuum advance does nothing for a curve! Vacuum advance to me isn’t very consistent either!
I should also add I enjoy your break downs of operations with carbs , timing and engine operations as such! Spot on and informative more than any other channel I watch! For a stock engine I agree with using the vacuum advance but some old lean burn engines and others ran better without the vacuum advance hooked up! In my experience it really depends on the motor design, compression ratio amongst 50 other factors involved..
As with carburetors they rely on the basic function of an engine being in good shape ….on a tired old motor you can really play with timing curves to make it run as good as possible ….sometimes eliminating the vacuum advance simply advance base and adjust total timing accordingly…
Need help !!! 64 Belair, summit 600... changed the intake and carb to the Summit 600, as soon as I fire it up the idle screams up, idle screw is adjusted all the way out
My carb does't have ported vacuum only manifold. Do I have to set a lower initial timing to compensate for the vacuum advance canister at idle??
That’s annoying - I’d see how much timing you can run in it without it acting odd.
If you have to astranomically close your curb idle screw and lean your mix screws, it’s too much timing.
Depending on how much timing your advance canister pulls, you might be able to get away with mid 20s for timing
@@ThunderHead289 Ok thanks Im a look into it.
@@ThunderHead289 Ok I got the transfer slots squared up. Now it doesn't want to idle on its own. Could this be a timing thing??
Hi Luke I tried to get on the progreesive igntion webste and nothing happened when I hit the iffrent links thanks Joe
Initial Idle screw/transfer slot adjustment?
Does Holley/Summit or Edelbrock (or other Carburetor manufacturers) provide a number of turns for the initial idle screw setting that will get us in "the ball park" for a good initial transfer slot/throttle plate relationship without removing the carb?
If you have vacuum on your ported port at idle, you have gone too far!
@@ThunderHead289 I assume if you go too far the other way (throttle not open enough) the vehicle just won't run.
I listened to KGGO as a kid.
I rebuilt my holley but it still seems like there's a fueling issue almost like it's not always delivering enough but other times it is. I'm not real familiar with how they work so I'm curious as to how the carb still pulls fuel when it's idling and where the fuel comes out of and goes into the manifold. I know it doesn't come out of the squirters until you give it throttle so where does the fuel come from when idling. It's a 600 cfm
I'm just looking for "fuel economy" because I bought a 454 😂😂
Trey Lewis lmao good luck I was gonna go with a 383 but I was like I’d be filling up every other day with that lol I ended up getting a 350 making 387 hp and 417 torque I’m happy with it
Forget it, if you want to play you have to pay.
I'd like to hear your opinion (if you have experience with) the initial timing on a Ford with efi & the EEC IV. Base timing is 10* Do you think it would be beneficial to set it at 12-13? My concern is that the ecm will have the timing over advanced at wot
I wouldn’t mess with settings on a computer controlled unit 👍
Nice video 👍A newbie question but if I don't ask I won't know, I have an Edelbrock 650 carb and bought an MSD pro distributor, would I still benefit from using this option? Thank you for any suggestions.
Absolutely!
Also, run one of the lightest spring and one of the middle of the road springs.
Add the proper stop bushings for 32-36 degrees of total timing after you set initial
Great info, thanks for sharing.
Great, now I can't stop dropping "myriad" into every conversation, LOL. Other than that, thanks for the carb setup tips, your vids are the best out there!
😂😂😂😂😂
Video was call ported vs vac advance
Am i right? set inital timing in gear for automatic?
Sweet tips. Thanks
56 f100 seems to run to lean how do I adjust carb
I'm confused now at 7:40. I thought vacuum is supposed to go down when the throttle opens...
Crockett85 - on the ported connection, there is no vacuum registered at the port. There is vacuum in the intake, it is just not passed to the port. Thus, with a gauge hooked to the ported port, it will read zero. Then when you open the throttle a bit, the port gets exposed to manifold vacuum, so it then registers. It appears that the vacuum goes up, but this is just at the port. If you were measuring the vacuum on the full-manifold port, the vacuum actually drops when the car’s RPMs go up from idle.
Is this method good for advancing timing for higher octane gas? Will you be able to notice a larger initial advance?
I’m not sure I understand your question - octane and timing are unrelated factors.
Spark knock and preignition are different forms of detonation
ThunderHead289 Wouldn’t too much base advance on a fuel like 87 cause detonation? If you tune timing based on ported vacuum, and then based on idle speed, how does this guarantee the best performance based on the fuel you chose? If you put race gas in your truck, you would be more concerned with total advance, but initial is important too right? I’m just trying to advance my car’s timing for performance.
Is this truck getting a fuel return line?
Bro tell me ur in Texas. I can use ur help on my 85 c10
Are you going to take the Galaxie on hrpt2020
Yes, I’m about to hit it really hard
I have a supercharged sbc 350 with a 671 it is running lean 18 to 20 with the aem afr gauge but burns my eyes like it's too rich why would the gauge read like its lean
A common misconception about lean is that it doesn’t have a smell - when a fuel charge isn’t properly burning due to timing or an out of spectrum ratio, you will smell it.
Contrary to popular belief, lean reeks too!
If you want to cross reference, review your plugs!!!
I was told to lock the timing at 32 degrees because of the motherthumper cam so I'll try that soon and go from there
Well the supercharger adds another bit of complexity where it’s simplified by locking timing although not ideal.
Give the units a look I linked and review it’s function - they are what I’m going to run on my supercharged engine.
My vacuum advance canister has two ports on it. Would I run both of those to ported vacuum?
No. Usually the vacuum port furthest from the cap is the advance. That second port is part of some smog/EPA/gas crunch setup. Depending on which car it was, sometimes those ran through a temperature controlled vacuum tree which opened and closed the vacuum source based on how warm the engine was.
In some examples, the automakers intentionally de-tuned engines when they were cold or at idle. Making the timing run late while the engine was idling caused the engine to start exhausting while the gas charge was still burning. Ford got similar effects to having a catalytic converted back in '73 like that. It made the engine run hotter and more heat under the hood coming off the exhaust system. They had to pass stricter emissions controls and did so at the cost of running the engine and exhaust manifolds a lot hotter. Sometimes the manufacturers used similar tricks just to help the engine warm up to operating temperature faster.
Anyways, if you're here and watching this video, then probably you aren't worried about this smog and emissions stuff. You're here for horsepower and drivability. Cap off the vacuum port on the distributor closest to the cap. Then connect the other port to whatever vacuum source makes you happy, and tune away.
@@giantpune thank you. I'll go take a look at what I did. It's a 74 Ford and even though I'm in California, 75 model years and older are smog exempt.
@@reidbarnes9851 By 74, ford was in full swing with all sorts of crazy thermal controlled vacuum stuff for emissions. If your engine still has most of that equipment still hooked up, I would suggest getting a feel for what everything is before you start taking parts off and plugging ports. :D
I think the subject matter and the advice in this video kind of assume all that silly emissions and smog stuff is gone anyways. There are some points like making sure your transfer slots in the carb are properly adjusted that do apply. But then any advice dealing with timing and vacuum, it feels like a fool's errand to try and tune your engine for horsepower and throttle response while still having to work around and fight those systems that intentionally de-tune the motor at idle.
@@giantpune most of the smog equipment was gone by the time I got the truck. I deleted some more of it. The vacuum advance that was on it wasn't working but only had the one port. The new replacement one had two ports.
I have a spot on my edelbrock 1405 that while im driving about 15mph, and i punch it, it will dog out. I cant tell if its not enough fuel or too much fuel. Otherwise everything else runs good on it. It seems fine when launching from a stop Just a flat spot when im already crusing and punch it. at start of power valve or such? I dont know what to do without a wideband O2 sensor to tell if its lean or rich when this happens
I am using manifold vaccum and a while ago i set the fuel squirt to the largest squirt since it seemed like at the time it was dogging out during launch from stop. But now maybe its too much fuel during a punch at cruise?
Its a 1979 ford f350 with a 460 engine, stock intake, 8 degrees stock initial timing
Ill try your tips out to see if it improves
What is your timing set to at idle, and what is your overall timing setup?
Like I mention in this video, timing is everything. Fueling and timing has a dynamic relationship, so they both play off of each other
@@ThunderHead289i am using manifold vac advance, and i have it set to 8 degrees before attaching vacuum. I dont recall the degrees once i hook up the manifold vac..i will have to check that again. Probably like 30 maybe, but i dont recall. Thanks for the tips i will try port vac again soon and see if that helps overall. The 8 degrees is because that is the factory recommended setting on tje valve cover lol. But thats probably also when you have all the emissions hoses , which i no longer do
If you set the engine up on the principles I do in this video, you will smile when you hit the throttle. It will probably ask for less accelerator pump also
@@ThunderHead289 interestingly though the original vacuum diagram for this truck does use manifold vac. That was with stock carb
Research and Build from the factory smog pumps, retarded cam timing timing chains, and ignition timing retard canisters were used also - the factory has to manufacture things to meet certain specifications.
Also, factory tunes are painfully safe.
YOU do not have to play by the same rules.
I dont like asking for advice but here we go i have a sb chevy with msd hei 9.71 com summit 600 vac second summit dull plain int comp little thumper cam 3in duel ex with summit bullet mufflers 700r4 trans stock converter.now in comp cam ad they say stock converter will work fine but im haveing idle problems.i put 34 degre total adv any more it spark knoks with 92 octaine and it has headers.with that being said at idle in gear i have about 2 deg of timming with vac adv at ported vac idl like shit.and yes i checked transfer slots there good.now do you think the coverter mite be the problem draging the engine down to much or do i need to look at doing something with hei.i really think i dont have enough initial timing but as you can see i cant put more timing in or it spark knoks help im at a loss any sug would be great.keep up the great videos there very helpfull.
What is your full initial timing?
I guess I didn't exactly understand your comment about your initial timing. But that's the downfall of the hei, it's hard to limit total timing - there is a simple method that I'd be happy to show you, I just can't via TH-cam - find my on Facebook, search thunderhead289 and send me a message
Time to plan on resetting my 3rd gen this summer! Burn rubber, and piss the neighbours off! Yeehhaaww!
Good for an FE Engine? what's wrong with FE Engines?
👍
Thunderhead i need your help with a 351w swapped into 1981 f100 poorly i might add your knowledge would be so much help can i email you
what ever happened to using the service manual and tuning your engines to manufacturer specifications.
Simply put, those settings are painfully conservative.
That’s why.
The manufacturers specifications were guided by corporate bean counters, government regulations, them having to warranty and service cars, etc. Carol Shelby and his crew were not out at the race track reading numbers out of the ford shop manual to milk as much horsepower as they could from his car.
hello
I run manifold vacuum because my engine seems to idle cleaner. No proof of this other than less smell of gas fumes.
Bobbie and Ian Guenter when you switched to ported did you advance your initial mechanical timing tho....
The responses to this video disappoint me - I must be hard to listen to.
This is not a video about manifold vs ported.
@@ThunderHead289 I enjoy all your videos and am sorry I sounded negative. My problem was limiting the advance on my Hei when I bumped up the initial timing. I took the easy way and used manifold vacuum.
If you find me on Facebook, I’ll send you a picture of how to correct that issue inherent in the hei ☺️
How can I do this by myself
💖🤔
No voice
I think that’s on your side
i can hear him fine
This comment is a great example of why some people might never catch on to fixing their own stuff. You have to be willing to dig into problems yourself and narrow down possibilities by deductive reasoning & patience. That's the best way to learn. In this case if you would have tried watching other videos you would have discovered by yourself the lack of sound issue was on your end.