EPISODE 103 Tuning Classic Car with Vacuum Gauge, Plug Reading, Jetting Autorestomod
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- เผยแพร่เมื่อ 1 ต.ค. 2024
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This week we use a vacuum gauge to fine tune our 1965 Mustang hardtop, how to read your plugs to know if the carburetor you are running is too lean or too rich. We also show what the exhaust should sound like at the tail pipes and how to use the spark plug wire removal test to find dead cylinders. We also give tips on how to test your car so that your changes will compare well with past test.
Thanks for watching!
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Just a couple of regular guys, and that is why I watch, no paid professionals following a scripted routine, NORMAL guys youd find in their garage in Anytown USA working on classic cars.
There should be a vacuum tree on the intake. Use one of the smaller vacuum ports to test from.
thanks, this is the answer I have been looking for!
Usually it will be around 1 to 1.5 turns of the idle mixture screws. You might also check for vacuum leaks around the carburetor base. If you are still having problems contact us on our web site and we'll see what we can do.
mustache guy looks like Freddie Mercury's brother
he looks portuguese
I wish you would showed what you have the gauge hooked up to and what lines are dissconnected and what vaccume lines are connected can you just hook up the gauge to the brake booster port on carb and cap off advanced timing good info but still can't pay attention to it because not enough info on how to hook up the gauge and to what
I have no idea what to hook this shit up to. Been looking everywhere. Makes me feel stupid cause i guess its just assumed you should know where they go.
Hook it up to the pcv vacuum going into carb
If your pump is maintaining the recommended pressure for the carburetor (Edelbrock says no more than 6.5 psi at the carburetor). First look to vacuum on the distributor, if the ported vacuum is not hooked up get that working and make sure that the vacuum can on your distributor is the correct one for your application. From there if the problem persist look to your metering set up.
Good point. That is where the drive comes in. You may need to back off of the timing a bit. We may hit that one in a future episode Mike! We appreciate you bringing it up!
THANKS !
This Vacuum Gauge tuning ,solved all my idling, stalling and misfiring problems !
My 64 Fairlane 260ci engine with Holley carb. was running on 15inHg. tuned all to 20inHg and all problems solved.
The Fairlane pulls incredible now, gas-milage has extreme improved and idles very happy.
you tunned your engine
but what your engine problem was?
best place is the vacuum tree on the intake. That is a "neutral" vacuum source (pulling form the total vacuum of the intake). If there is no tree, find a single port plug that will fit that threaded opening and use it to establish the vacuum.
True. The larger the cam the worse your vacuum signal. But even in those instances a Vacuum gauge can still help you out with figuring out what power valve to run. Note that we like vacuum advance for street engines or mild performance engines. If it is so radical that the signal is below 10 inches of vacuum no matter what you do then you are going to have to apply a whole new set of rules.
It sounds like the new carburetor is running too "fat" if it is flooding. You'll most likely have to play with the metering rods. We recommend checking into some tuning guides for the Edelbrock. Also, make sure that you check your set up with the vacuum gauge. youo should have between 15 and 20 inches of vacuum at idle. Private Message us if you have any more questions.
I have a Chevrolet 454 V8 on a P30 chassis. What is your opinion on these 'fuel injected' aftermarket systems for vehicles like mine. David 🐈
Depends Barry, most of the suspension will work. power brake boosters won't. spindles will. Brakes are the same. No sheet metal any where on the car will bolt up. You might use the floor pans BUT there will be heavy mods. Check Autokrafters, they have a Maverick catalog that will show what is available.
Couple of things: Check to see if you are getting fuel down the carburetor (engine off). If you see fuel hitting the throttle blades in the bottom of the carb (use a flash light) you are good on fuel. Did you move the distributor? If so you may have it either advanced to far or retarded too much. Check the Ford service manuals for proper idle screw adjustment on the one barrel. Too much and you'll run rich or flood. To little and you will not get idle fuel.
ulysses, contact us via private message here and we'll give you an e-mail address to correspond with us about your car.
hey guys thanks for the video. I enjoyed it. I just started tuning my carb with a vacuum gauge and this video helped a lot. I was able to raise my vacuum from 14hg and idling like crap to 21hg with a beautiful smooth idle. I have a question about the timing adjustment with the vacuum gauge. 1) are you still using manifold constant vacuum? 2) did you unhook the vacuum advance?
Stumbled on your video. Thanks for posting the very useful info. I plan to try these tips on my big block 70 Chevelle .It’s a carbon footprint nightmare. My wife hates to ride in it because we always smell like fuel after going for a ride
Y’all explain this better then anyone else
You might check for vacuum leaks. If a Holley won't change vacuum and doesn't start to stumble with the mixture screws in, it may be a vacuum issue. Get that worked out and then start tuning.
Try using the vacuum gage rolling in high gear @ 40 mph adjust the timing to the highest setting after you have done what you did. The movement that you make by turning the distributor will be ever so slight a 1/64 at a time. You can only do this with a tiny hammer, I like to use one that I made from a 3/4 inch brass bar stock an inch and a half long. You just let the weight of the hammer touch the vacuum chamber while the hold down bolt is snug but not tight. Vans are easy because you don't need to stop and get out. It does not matter if the engine is computer controlled or not because what you are doing is increasing the range of advance. Every engine is different because of machining and the condition of the timing chain. You get the best performance and mpg by setting the timing this way. Sometimes you have to back it off a bit because of a slight ping but that depends on the fuel you're burning and how fast the curve on the distributor advance is. This is what I learned running a chassis dyno back in the day but you can do it on the street too it just takes a little more time. The video was entertaining and you got everything right but you have to know how critical a tiny tap to the rotation of the the distributor really is it could mean a couple of miles per gallon and I'm not kidding have fun and keep on doing the videos good job!
What would also be really helpful is if you actually showed what you are doing ON THE ENGINE, rather than just keeping the camera on yourselves. e.g. where is the vacuum gauge hooked up? What are you doing with the distributor wrench. Work on the usefulness of your videos. Thanks.
Well, since this was shot in 2013, we have.
The vacuum port is going to be in different locations on different engines. We are generalizing here.
Did Vinnie put you up to this? LOL He actually has a multiple carb set up on a 350 in his Gen 3 Camaro. We'll look into it for sure.
We'd check the wiring to make sure that the firing order is correct. Go to our web page and contact us and we can send you an image of the firing order to help you out.
Depends on what you are tuning. Unplugged it can help you set the initial timing. plugged in you can set idle mixture and check the vacuum drop under acceleration.
We'd recommend getting into some howto videos. Check out Miller Welders and see what they have. Eastwood also offers how-to videos on welding. Best thing to do is to get the basic knowledge and start out on sheet metal (salvage yard stuff is great if you have a You-Pull-It yard around, fenders are usually less than $40. Cheaper than sheet steel.
Jeff likes Guinness Stout. Vinnie likes Rum...bloody pirate...
These guys know their chit
Don't know about these old classics but most vehicles have a plastic grommet on the firewall to where you can run wires or vacuum hoses into the cabin that way completely bypassing the possibility of the hood crimping the vacuum hose. So what if you have to use 10 or more feet of vacuum hose the readings will be the same no matter the length. Great video on the importance of good vacuum and base idle!
Good point DJ.
Drill and weather strip with some seam sealer, instant custom hole in the firewall
When the car is running badly after all the things we've shown you that is a good indication. If it is running rich (black smoke from the tailpipe) that is also a good time to go in and work on the carb.
Thanks for the kind words Pavel! We're planning to delve into the Fox bodies '79-'93 Mustangs very soon. We can only imagine the trials you must face doing an American car in the Czech Republic...
Great video!learned a lot! So, question for you guys. Have a 65 TBird, 390 CI diagnosed with bad carb. Replaced with a Holley 600. Engine idle is a little rough, with a little flat spot accelerating. Also, hard to start after running to normal temp. Runs well otherwise. Any thoughts? Love your channel. Wish you were near cause I’d definitely come see you for a tune up (which it had less than a hundred miles ago…by a professional 😊)
Thanks and keep up the excellent videos
Great comprehensive video for someone that is just learning older style carb and distributor tuning.
Yes, these things will work on any carbureted engine.
This video had some valuable information, thanks.
Thanks for the video. I been working on my 1974 dodge van and your tips helped me to get it running a bit smoother.
Sounds good! Vinnie will be happy to know that we have another 3rd Gen Camaro/Firebird owner!
Hi guys, I've already seen all your episodes. It's one of the best channels on youtube. Lot to learn :) and I can use many of your tips on my 1984 Ford Capri 2,3l V6. Greetings from Prague, Czech Republic and keep on doing those great videos. Thanks, Pavel
Great tips & help again + going to keep vacuum gage in car tool box for long drives Thanks !!
Running air/fuel ratio gages on my XKE, helps to tune the 3 SU HD8 carbs for power
I have a 67 Mustang 390 dual 4 barrels it runs off of the back carburetor it has a electric choke on the front carburetor shouldn't it have the electric choke on the back carburetor since that's the one that it's running off of until you kick it down and get the front four-barrel carb working?
Its pretty amazing what a vacuum gauge can tell you with an old car, or any car for that matter.
Hey guys I'm having a really annoying misfire/poor idle issue with my 68 L6, wondering if you could help. My vacuum gauge, attached to manifold, reads about 17 at parked idle it drops well below 15 in drive. Timing is set to about 12. A/F mixture screw seems to do nothing on carb. New vacuum hoses, new distributor, cap, and rotor (also switched from dual diaphragm to single), New autolite 1100 carb, new vacuum hoses and entire new engine (old one had bad low end knocking). STILL no matter what I seem to adjust or switch out, I have that hiccup misfire sound, poor idle, and really, really poor gas mileage. I'm lost here. My multimeter numbers jumps around when looking at idle too, its anywhere between 300-560 rpms.
Dakota, Jeff is noodling on this and will respond in an e-mail.
Great video on setting up a carburetor with a vacuum gauge . I on my way to get one now . 👍🏼👍🏼
I have the same issue with my vacuum advance hitting the radiator hose. How did you reposition the distributor to avoid this?
I know a sc tag when I see one 👍
Hi Who you connect the vacuum gauge ? i have 1405 edelbrock 600cfm in manifold port or distributor port ,thx (sorry for my poor english i m French :-) )
Connect to the Intake vacuum port
I have a 1956 Oldsmobile with a 324. Where do I hook the hose to??? I don’t see any place to put it. I’m lost. Does anyone know out there ???
It looks like on the 324 the only viable port is the one on the carburetor that controls the distributor. You could tee into a test like to pull vacuum, but I'm not sure how accurate the reading would be from that port.
Very comprehensive and well explained, thanks. Subscribed!
How would I know if my carburetor needs to be rebuild
Great Video .ole Man At the beginning reminds me of my Neighbor. Lol
That was my dad, he passed in 2016. He was a rip!
Thanks for the great video. You are awesome!
Thanks for the information… I was born in 83 so I know more about fuel injection but I recently bought a 72 F100 because I’ve wanted a bump side since I was a teenager. I’m soaking up this information like a sponge…😄
Do you connect the vacuum gauge to the carburetor or the intake manifold to perform the diagnostics you showed?
Intake manifold.
Low vaccum, then do you close the idle mixture screw in more to restrict air?
Not sure that's right to time the advanced just by turning it because the car is not under load.
Using a timing light is surely best.
Both are equally effective. Both require drving the car to see if the timing is what that engine needs.
Glad you guys put this get there. Subscribed because l learned much to use on my new old 66 Impala I just got for my 64th Bday. Great content n well done.
I would kill who ever gave me a piece of shit Chevy!!!
hi, could you help me how to connect the vacuum wire ford 460 lincoln in 1970-71?
It will need to go to a port on the carburetor. If it is a stock carb, it is usually on the base plate.
I use a vacuum gauge because my timing pointer isn't the correct one but anyways I can get nice high vacuum reading. I shut it off and start in it and my starter labors so I have to back it off and any reason for this. 82 c10 305, lunati cam with 218 duration, edelbrock 1406, new distributor.
Hey guys, I have a 71' F100 w/302 and it idles in the 18-20 range. Though it flutters continually between that range and occasionally slightly smooths out, but not completely, for a few seconds and then back to the flutter...Any ideas what's causing this condition?
I wish you would do an autolite 4100 air fuel mixture video
We have an Autolite 4100 on our '72 F100. It's kinda piggy right now so that might make a great video!
I have a 66 Mustang with an Autolite 4100 that I just can't get right - not much on youtube where someone does a live setup of one of these.
I will say that the 4100 is VERY picky about airflow and vacuum leaks.
Can you time a motor with a vacuum gauge? My motor seems happier at a higher base timing (The engine bay sticker say 10 degrees and I've got it running nicely at 13-14 BTDC) Could that be due to the age of my motor or the carb mounting gaskets are in need of replacing?
These guys may be excellent mechanics, but the clowning around gets really annoying and distracts from the message. Just my .02
Well like my daddy always said, not everbody has your sense of humor. We clown like that no matter what.
I agree. To each his own
Hi guys got a huge question!!! I got a 87 Trans am I been working on and can't seem to make it run right hope u guys can help!!! Ok I replaced the carburetor (e4me) q-jet electric one to a edelbrock 1406 because the old one was giving me nightmares! and I also changed the computer controlled distributor to a hei set up so I think I timed it right and all but now it runs rough and floods when I floor it. Now it eats gas like a fat lady at a buffet! Also electric pump still connected in the tank
It's funny how so many of the younger guys haven't heard of the magic of vacuum in tuning. So if you run a big cam with a lot of overlap, your vac readings will go down. Then, at some point a vacuum advance doesn't help, especially if you need to raise your idle speed.
Inches of mercury not inches of vacuum.
RIcky Rick As long as you have a form of reference it doesnt matter if you call it a chinese name. th-cam.com/video/JDPwY0LbRVY/w-d-xo.html
Pretty sure they knew what you meant lol.
Bring back Gramps!!! He's the man!! I mean you guys rock too with the solid info and stuff, but bring him back!!!
Sadly, pops passed away last year in November. I miss him every day.
AutoRestoMod Muscle Car Resto and Modifications my respects for the loss.... thanks for making your show. I have learned a great deal for them.
Can I disconnect the distributor advance hose that plugs into the carburetor and attach a vacuum gauge hose in that carburetor spot or should I place the vacuum gauge hose somewhere else in the carburetor or intake manifold. I have a 200 inline 6 engine
66' coupe
Hello guys i have 95 FIREBIRD with a sbc (355) w/ th-350 im having problems carb or pump problem not sure!! Under a heavy load im hearing popping noise around 3000-3500 rpms running lean im guessing, to get to higher rpm i have to ease of the pedals but she stilll crawls up to higher rpms. (edelbrock 750 totally rebuilt and holley blue ) i need some help..
Just learning so much from this channel! Hi again, I just did my first vacuum tune on my 71 Lincoln Mark III (its got the Motorcraft 4300 on it). Upon starting the car fires right up and idles smooth until I tap the gas to begin driving and the choke opens then it idles rough. Sitting at the stop sign at the end of my street I can feel the whole car shaking. After 10 minutes of driving sitting at a stop sign/red light, no more rough idle. Made sure the car was warm, setup the vacuum gauge and its at 20.5/21 inches of vacuum at factory idle mixture screw settings and even with the screws all the way in or all the way out I'm at the same measurement with no change but needle dances more than what the good tune you showed in the video. I do however notice my fuel pressure gauge is bouncing from 6 to 7psi at any idle mixture screw setting. Something other than the carb is the issue?
i just put in a new single barrel carburetor and my bitchass six cylinder straight 250 will not start. it and im adjusting my fuel and idle mixtures and it gets close to starting but wont start. It has a choke but its vaccum is split into the carburetor and then the choke? should i get the distributor with double vaccum or should i just keep adjusting bitchass idle/gas mixtures??
Just finished doing this with my Chevy Vega. A bit easier as there is only one idle screw on the 2BBL, but it runs great. Thanks!
hey autorestomod, i have a 1965 ford mustang coupe 302 with a 1986 302, 3 speed trans that is automatic. the question is that the block has smog parts on it and has original 2 barrel intake and carb setup. can you pleas help? suggestions?
I need to learn how to weld! Need your tutoring please and thank you! Both my cars need body work. Quarter panels and floors need to be redone, living in Chicago Illinois suck because of the snow and salt.
great car
Thank you! Learned a lot off this video and was fun to watch
YES! I like it. Doing it right, great job
Thanks for the kind words.
Hey I'm restoring a 1970 Ford Maverick would it be fair for me to assume that most parts used on the mustang can to used on the Maverick
Hello I have a 4150 Holley and eldelbrock intake on a 289 as in the video, manual gear, 800rpm. I test vaccum on the manifold, on booster line, it is the same low value 10inHg I tried adjusting idle mixture but nothing changed. Gaskets are still soft I don't see a leak. I know the engine is tired but it is very low and affect brake booster. I had a 289 stock with 2100 2 bbl and vaccum was stable at 16. Can you give me a piece of advice, engine tired or carb issue?
Which 4150 do you have? If you have a 600 cfm, I might look to timing issues. Id recommend advancing the timing a bit and see if the idle comes up. Contact me directly if that does not help. jford@autorestomod.com
I have a question i have a 1965 mustang 6 cylinders with an engine 200ci i got the engine rebuilt and everything but it souns like its going to turn off and the engine shakes alot what can be wrong with it
I have a 1979 f150 7.5 whit motorcraft Holley carburetor (4180) just want to know what size of power valve this come whit originally
Unsure, I would look at calling Mike's carburetor
Phone: 888 689-9758
Do I need to buy a fuel regulator for this set up?? It has two pumps manual on the engine and electric in the tank
Sweet, thanks guys. Yeah, Vinnie mentioned it once or twice. He was real insisting about it, now that I think about it...
What part of the carburator do you need to attach a hose or screw in. Mine is a 1 barrel carburator
Careful not to "over advance" the timing when tuning with a vaccum gage. The fuel today is not that great...
Learned alot, thanks.
This is absolutely amazing.
I love showing the gauge, but nobody shows where to attach it.
Honestly just find a vacuum port on the engine antique manifold. The problem is they're all in different spots on different makes of engines even when they end a company line like Ford et cetera
Thank you guys so much!! I wish I knew where u guys have ur shop at to personally shake ur hand!! Great teachers.. I'm just a troubled 25 year old trying to revive my dream cars!! I have the 87 Trans am 5.0 and a 88 firebird 5.7 which both need alot of work so ull hear from me more...
Hi, I live in Quito, 2.850 m over the sea. Please, can you tell me how much I can expect read at the vacuum gauge in my 383 stroker motor ?
That will depend on the cam Mio. If you are running a high lift cam the vacuum signal will be low. Some cams are so radical that they will only pull 12-15 inches of vacuum. Make sure that you have no vacuum leaks around the intake and carburetor. We use 24 .oz of water and a tea spoon of dish soap mixture in a spray bottle. Start with the intake and move to the carburetor. If the idle picks up at any point you have a vacuum leak.
AutoRestoMod Thanks very much for your attention.
Tried tuning a car with a vacuum, all it did was suck. Cleaned my car and garage though....j/k
👍👍
Dad jokes! I LOVE'UM!!!
That idle should CHOP CHOP.
Not if it has a stock cam...
😎
Great video guys, thanks. I learned a lot, and it'll come in handy for me down the road. If I ever get down to SC I'm bringing beer.
When I watched your video It Was Grrrrrrrrreat But 1 questionfor You I have a motorcraft 2150 for a Carb and I understand everything . where should the IDLE Screw be at ?????? Unscrewed all the way??????
+Stash Murawski I'd say around 600 rpm in drive. BUT you should look to the manuals for the right idle setting as long as the car is otherwise stock.
This must have been filmed in oklahoma !
Close, it was Aiken, SC.
i am new to tuning and building. i have EVERYTHING you recommend. just no knowledge of what im looking for other then a smoother sound. thanks for the info. good video
edit: after watching this and a few other videos i went out and hooked up my vacuum gauge and was at 5. i twisted the distributor as far as i could and brought it up to 17, i think im off a tooth, but i also have a large (not some hog ass race cam though) cam, a comp 268xfi. so 17 may be as much as she wants but it definitely sounds WAY BETTER also readjusted the idle screws on my oversized demon 750 and it does not smell nearly as rich. thanks man great video
Go look at our timing video too: th-cam.com/video/Qz_cYOe2B20/w-d-xo.html
I have MPFI from 1987 and my Chevy Sprint Turbo is running like crap. I think its running rich because the tailpipe is black, plugs are black, and I'm getting horrible gas mileage - like 15mpg.
I bought this car of a motorhead for really cheap and I think he had a bigger turbo in it at one point for drag racing. Now trying to undo everything he may have done... It seems like it has tons of power and it accelerates like a boss. The idle is kind of rough though. If the motor is not fully warmed up it will occasionally miss or backfire and the exhaust will make a strange gurgling sound, almost as if liquid gas may be washing over the valves preventing a proper seal.
I replaced the spark plugs and the old plugs were gapped WAY too tight - about half what is recommended. Why would one do this? Can I assume that due to higher boost pressure he was having pre-ignition even with the timing retarded? The timing cover with the marks is missing so its hard to check with a timing light. Would retarded timing cause poor fuel economy?
I am going to go advance the timing right now... not quite sure how far to turn the distributor to get a few degrees, but I think I'll just go by ear. I don't have a vacuum gauge.
I have a feeling he put in bigger injectors but I'm not sure how to tell? Can injectors be too large? Will the 1987 ECU account for this by shortening the open/close time?
He put in a bigger fuel pump - could it be getting too much fuel pressure? I don't see why he would have upgraded the fuel pump if he did't put in bigger injectors. But isn't the whole fuel rail assembly basically a pressure regulator?
I can hear the fuel pump RPM varying quite a bit and I feel like it should keep a steady RPM? It sounds like it whines louder when I give it gas... Maybe its supposed to? I can hear the pump RPM vary directly with the engine RPM when the engine stumbles a bit at rough idle, but which do you think is causing which?
I'm half-way tempted to just slap a bigger turbo on it and see if it runs better. Hahaha
Waaaay outside of my strengths bud.
This is hands down the best video on how to use a vacuum gauge I have found on TH-cam! Thanks for the great video, going to apply it to my Motorcraft 2150 on a 79 CJ7 I bought recently. I am new to carbs and this is a huge help. Gotta say though, while the information is terrific... Mr.Fords makeup did it for me.
G M th-cam.com/video/JDPwY0LbRVY/w-d-xo.html
a holly what... What's the full name cause I just bought the same one and ism what it is haha
Adjust carburetor first, then Distributor?