Causes of Weber DGEV Hesitation 32/36 Volvo 122s Amazon
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- เผยแพร่เมื่อ 10 ก.พ. 2016
- UPDATE 2018: Fuel pressure was 100% the cause of my Carb problems. Cheap Autozone gauges were giving bad readings. Mr Gasket Fuel Pressure Regulator is the best budget option from O'Reilley's Auto Parts)
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IN MY TIME TROUBLESHOOTING MY WEBER HESITATION ON MY 1967 VOLVO 122 AMAZON, I FOUND SOME INTERESTING TIPS AND THEORIES.
ALSO, Weber versus SU HS4 on Volvo B18, B20, MG and other cars.
Here are the forums I came across with great information about the Weber 32/36 DGEV I am dealing with. It could be so many problems, how do you know what us causing your hesitation? Throttle plates? Idle mixture? Incorrect Jetting? Choke adjustment? Idle Circuit? Accelerator Pump? Watch to learn more!
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www.mgexp.com/phorum/read.php?...
www.jeepforum.com/forum/f12/we...
community.ratsun.net/topic/163...
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Thank you! I have. a 73 Nova with 250 engine and I am on the hunt for a Weber 32/36. I like the way you explain the tuning and thanks more for no stupid rock music in the background!
David, thanks so much for making this video. I have been messing with my recently acquired ‘69 1800s with a Weber conversion. I have been chasing issues that now seem to be normal for that carb. I really enjoy all of your videos. I’m on my 14th red block Volvo since 1982 and I am blown away by your knowledge. If you ever find yourself on the eastern shore of Maryland my home is open to you. Thanks, Kevin Langan
I wish more videos were out there like this! A+
I have 0 knowledge with carburetors. Zero experience with carburetors and I can tell you that I received a new Weber from my brother off his Toyota, it’s been HELL getting it dialed in for my Datsun 620, and I’ve been watching your video to get some insight. You’ve done all the digging for me and I must say thank you. Also you’ve answered a lot of NOOB questions I had and also it’s helped me out some. Thank you for posting this video
Thanks for this video. I've owned several 122s and 1800s and would never put on a Weber carb. However, I might be replacing the old carb on a 1971 Fiat Spider and it will likely be a Weber 32/36.
A few remarks:
These old carbs were jetted to deliver 100% gasoline. But modern gasoline usually has 5-10% ethanol in it. This percentage of ethanol has a leaning effect on fuel mixture everywhere: jets, accelerator pumpage, idle mixture, cold start enrichment. That might explain the tuning/driveability issues.
As for the SU vs. Weber debate: the SU is a constant vacume variable venturi design like you also see on many 70s/80s/90s japanese motorcycles. (fi.Keihin CV) I think for fuel economy (part load) the constant vacume variable venturi design is the superior design provided it is tuned correctly using the right jets, the right needle profile and the right acceleration enrichment.
Back in the 1980's carb development slowely came to an end because EFI was taking over.
The most modern carb i worked on was a Ford VV ( a Variable Venturi constant vacume design just like the SU but in this case a downdraft from the early '80's, it had a single venturi on a 1.6L 4cil 8valve engine + automatic choke using both water and a bi-metalic e-powered spring for engaging and disengaging the choke)
Those VV carbs were bolted on to the same manifold as the older conventional Solex, the VV was finnicky and temperamental but once setup/tuned correctly they were about 10% more fuel efficient then the conventional stock Solex single barrel on earlier 1.6L models. With good torque curve and good light-throttle responsiveness.
I'd say, carbs with constant vacume variable venturi design are better then any fixed venturi conventional carb.
Millions of Japanese motorcycles have proven that.(heck, even Harley's used japanese CV carbs!)
I have now owned two weber 32/36 carbs. Webers are notoriously fickle when it comes to tuning. I changed out the stock carb in my Isuzu pickup for the weber 32/36. The place I bought it from passed themselves off as an official weber dealer, but they were selling knock off webers made in china. I found this out the hard way when I tried to order parts from redline weber. Genuine webers will have white colored electric choke covers versus the black color for the knock offs. Also real webers will also be stamped with the metal weber logo versus the sticker that comes with the imitation weber. I had all sort of problems with drive-ability and engine performance with the first weber. Finally I gave up and bought another 32/36 that was actually genuine weber made in spain. My truck ran much better. However I still had issues setting the lean best idle. To make a long story short, I re-jetted the weber for fuel economy and then changed out the primary idle jet until I could set lean best idle with two turns out. Also weber 32/36 have a tendency to leak air around the throttle shaft. The cheap plastic washers tend to fail prematurely causing driving issues. Pegasus racing makes metal replacement washers/bushings that you can replace the plastic ones with. Once I did mine, it was like I had a new weber. Best $20 I ever spent.
thanks for the tip! my Weber had the white choke and I replaced it with a "genuine" black one.
Colours wrong way round David, according to the Poster Darth Volvo!
Your application didn't happen to be an is Isuzu 2.3l did it? I'm trying to get my truck to run again. It's starting hard and I have to stomp it to keep it from stalling.
Love the gauges, pretty cool explanation.
I finished my SU to Weber conversion with a Holley low pressure regulator in front of it a week ago and could not be happier. My Amazon was running ok with the SU's until they dripped fuel so I sent them to a shop in Wichita Kansas for a rebuild. They came back pretty but ran worse then before and needed daily adjustments had sticky chokes and fluctuating idle. The car was a challenge to drive between almost stalling idle to idle revving to 1500rpm changing back and forth many times on a 2 mile drive. Then a year later they started to drip fuel again. Now with the Weber it starts immediately cold and hot out of the box and runs smooth. Perfect daily driver now. If you want performance look into mikunis. SU's are a pain. Mine look pretty on the wall though. Expensive garage decoration is what they are good for.
Thank You for sharing, some good stuff in the video for me; Installed on a 258ci Jeep
Very useful. Great job. Thank you for posting .
Keon Frederic thanks for watching!
thanks for the pragmatic approach dude.
When returning a DGEV to service after a 7 year restoration of my 122 I found a stuck ball in the accelerator delivery valve and jet. Freeing that helped stumble some but it has another ball in the circuit close to the diaphragm. I will check that If I don't get my SU's fixed first or find a manifold for a single DCOE. The Haynes Weber Carburetor Manual has been a great help.
i used to run a DC36/36 on my B18 and B20 and it worked just super. is was jetted for the volvo from the manufacturer.
I think something worth mentioning, (as I stumble with the Weber on my 144) and that was touched on but not expanded on, is that Webers have a fixed venturi. SUs have a variable venturi. A 32/26 is a purely mechanical contrivance. Throttle blades open, (progressive or not) whatever vacuum signal is present through that 90 degree bend, sucks whatever it can through the opening it’s forced to deal with, sized correctly or not. SUs can be too big for the engine, but the vacuum signal pulls the piston up in front of the throttle blade determining the amount of air and fuel moving through the (now) constantly self adjusting venturi created, as well as the amount of fuel through the jet. The weight of the piston in a larger SU (i.e. for a Rolls Royce) will have a factor, as well as stock jet sizes, etc. The point being, the engine internals (camshaft, ports, valves, heads, etc) are the determining factor of how much air is used. The loose nut behind the steering wheel gagging the engine with the accelerometer is removed from the equation. In general, (not you specifically) folks tend to forget that engines are only air pumps, and carburetors are metered fuel leaks. The job of a street driven carburetor is actually to restrict air flow, forcing the engine to suck fuel out of it. Not dump fuel in it. Accelerator pumps only exist (to my knowledge) on fixed venturi carburetors to ease the transition from the idle circuit into the throttle circuit where the vacuum signal can better regulate fuel flow.
I switched to the Weber because it was free, and the set of SUs I had were a mismatched pair, and cobbled together from different parts carbs scrounged during years of working on old British cars. The rear carb would only idle down if one of the three screws in the top was removed, allowing the piston to return. Yes, the jet was centered. The Weber is just as big a pile. I’ve sourced a good set of SUs from a B20, and need to get to Richmond to pick them up.
Let me know next time you’re in Asheville, and I want to see progress shots of the 164.
Reid.
Good video.
On the comments on manifold design (especially the too much turbulence one) there are literally thousands of OE applications that use a downdraft on an inlet pretty much exactly like the one you have, the air turning the corners isn't a problem nor is the different runner lengths between the cylinders.
Longer runners are not better than shorter ones, they both have advantages and disadvantages.
The coolant connections to the manifold provide a regulated temperature, when the inlet is cold it heats it and when the inlet is too hot (as may be your case with the exhaust location) the coolant flow helps cool it.
I think your issue is jetting rather than the carb being unsuitable for the application. As I said there are 1000s of OE setups and 1000000s of cars using the same basic downdraft setup. Jets are cheap so I would start from the beginning and go through the complete process from the start rather than just hope what's in there is right.
Never had anything to do with carbs but video and information was very interesting. Good luck with your car.
+strokermk3 Thank you.
When the vacuum level at the carb goes to very low or zero, the only thing that can give you fuel is the excelerator pump..More pump shot is needed. Another thing is manifold and carb baseplate heat. Carbs are refridgerators when mixture goes thru the low pressure area beneath the carb and in the manifold. good response demands a hot carb base and manifold. Use avilable sources of heat to make it work...exhaust heat to preheat the air going into the carbs incoming air, water or oil thru the baseplate and manifold to keep it warm. A cold manifold causes the fuel to fall out of suspension and cling to walls of the manifold when you step on it and vacuum falls.
Hi can i put a blank plate on my 32/36 dgav secondary side diaphragm will it work well
Dave, youre doing great man.
oh and the bit about the carbs having to utilize compromise. that makes sense. mine only bogs if you try to pedal it hard, but if you are linear in your apllication its fine. i guess ill just deal until i save enough for a 3sge swap that has efi. the electronic conversion i did for the ignition did get rid of all sputters.
When you mash the throttle at 8 min the accelerator pump should provide a stream of fuel as you quickly stab the throttle. That is why it is called acceleration pump. I've driven Volvo's with perfect SUs Webbers and zenith carbs they all run extremely well if maintained and a little care taken during setup. Hook up the coolant line to your intake it goes from too cold to too hot from your headers. I bet you have some vacuum leaks and some minor jet adjustment that needs to be done. It is very easy on a Webber plus you have that wide band that we never had while we dialed ours in using sound, feel, smell and only checking plugs a few times.
Excellent content!
Hi David, is there a Weber side draft DCOE type that would suit your application..
....I'm having the same problem with dead spot on take off. Have just found out that an uprated vacuum advance unit is required if you convert to weber 32/36 DGV ( lucas distibutors, anyway)
whay do you use a 32/36? i was using a 36/36 and the 38/38 is the one to have as the 36/36 was to small and my engine was struggling to get the air it needed. i think i maxed out at 140-160 hp. i guess bigger car's had given my engine 30-50 hp more.
Good and honest info...thanks
of course
did you say that at idle the butterflies got to be completely ''sealed'' and then the carb gets air from a specific circuit? did i get it right?
Mine does it at high rpm like on interstate it’s fine at low what would that be
hello i have a single su hs6 on my b20 i tuned it but i keep getting a slight stutter at very light throttle while driving at any speed if i accelerate hard for instance its fine its only at slight throttle i tried some different timing degrees and richened the jet a bit but that didnt work tomorrow im gonna try a tiny bit more damper oil but was curious what you might think
I believe all the many hesitation stories about new Weber carbs is float height and throttle shaft bearings. Heres my story. My new Redline Weber dgev kit k646..I smell gas sometimes and when spraying starter fluid/carb cleaner at throttle shaft bearings{4}.. serious vac leaks there... engine almost dies. then a damaged plastic float looks like pliers damage and measurement was at 44mm instead of 35mm.. and have a very weak needle valve spring. I just ordered a new brass float, float measure tool, needle/seat {size .200} and ball bearing throttle shaft bearing. Been through hell..checked/replaced everything else so far..intake man gasket..egr delete plate.. plugs.. wires..vac line dist to carb..mix screw..use vac guage etc etc. on a great motor finally checking the carb float measurements removing the top is frustrating but do this 1st dont trust factory. ill post progress in a couple weeks. good luck.
I believe I have the solution of your problem. In my case I have installed on a Suzuki Swift, but my case is that my engine has dual advance vacuum on the distributor (one for idle and the other for ported vacuum). Right now, since the original unit was damaged, I got a single vacuum advance pot for the distributor. I had it hooked up to the ported vacuum of the carb and I (in some way) managed to clear the hesitation but not much. One day I change the hose from ported to manifold vacuum, adjusted the idle and the carb setting (just idle speed and maybe 1/4 to 1/2 turn on the mixture screw) and the hesitation was gone. Now, I´m not saying that is the answer but many of you having the damm hesitation problem should see if this helps, since (I also looked up the same sources you did plus more) and there was a person on the Toyota FJ forum that said that some engines that have dual advance distributor with just the ported vacuum hooked up will show hesitation and even engine dieseling after shut off (both things happened to me) and that´s because the idle speed screw is just opened enough to create those conditions. The rule is that the butterfly of the carb has to be as closed as possible if not, the whole system of the carb would not work right.
Nice set of information. I just got done reading up on a few similar sites when I ran into this same problem on my 1979 Toyota Celica 20r. I read basically all of the same bits. I've only had the carb on for a couple days now, so I haven't had time to tinker on it (other than the basic fast tuning techniques). It looks like my hesitation isn't nearly as bad as it is on your car but it's still annoying. I bought the carb for my application and expected it to work perfectly after minor tuning. Now that I know there could be a number of different factors leading to the carb not working perfect it has me wishing I purchased a different carb (specifically the 38 synchronous). Oh well live, learn and have fun tinkering all the way.
I recently found that my fuel pressure was way off. I didn't touch on it in the video but it surprised me to read how sensitive carbs are to over pressurizing. I now run a Mr gasket FPR with no problems.
I'm running a Holley fuel pressure regulator at a hair below 3psi. It doesn't really bog under 1800 like it's going to die but it lacks power and doesn't start screaming until above 2k. The power difference was very significant (compared to a poorly adjusted stock) for my application so I'm still happy. Went from 15.6 second 0-60's to right around 10 seconds.. Also it's on a 3-speed auto 20r.
I also spent a few months fighting a bad gauge that was misleading me. are you on a mechanical pump?
I also spent a few months fighting a bad gauge that was misleading me. are you on a mechanical pump?
Electric, I've read about people not using regulators on mechanical pumps though. My stock electric puts out 5 psi so I figured a regulator was a must.
I have a weber 32/36 that I just installed on a 1979 MGB; but when accelerating and taking the car to 4500 rpm, the car stays at those 4500 rpm even though the carburetor is at idle speed. I have to rev it several times until it backfires and then drops the rpm to 1000. How can I fix this problem?
So what jets did you end up with
I had to drill a 3mm hole to the dgv's primary butterfly to make my b20 run "properly" with a K-cam. It drives nice now, not much stumbling. The mixture at idle is ok, low to mid rpm cruise is too rich, and wot high rpm too lean. Not much power and bad mpg, and its pings easily. I have tried everything.
The carb is probably more suitable for a low comp b18 with A-cam.
2x45's were too noisy and the SUs are quite "exotic" but ill give them a try.
love the car talk.
+eric jones Thanks for watching, Eric :)
There's a rectangular plastic piece that fell out as I took the top off my carb. Any idea where it goes?
Jenny von Henkelmann if theres a small rectangular hole in it, it goes on the the top half of the carb, (that houses the hoke butterflys) and it fits in a little cubby hole and the arm thats connected from the choke to the butterflies goes through that hole on the plastic piece
David, you said your fuel pressure turned out to be 100% the problem; was it too high, or too low? And, if too low, what was the problem, - a failing fuel pump?
Hey bro. got your carby sorted yet? If you think porting your manifold, Match porting and head porting. Have a look inside the carby and observe the lacksidasical moulding from initial casting. Im sure the steped base and square inlet tubes (esp. where it contours to round) can be a total air velosity restriction resulting in lean mix. Ive polished my 32/36 and let you know when I install.
considering doing dyno testing with head ported and extractors.
Marty Barman my biggest help was a solid fuel pressure regulator. It was over-pressurizing and fighting the Jets constantly. My aftearket fuel pump was overdoing it
On my MG changed out the smog Stromberg for HIF Su best decision ever made. Now on my 71 Morgan with the kent (ford) engine I am runing a factory original 32/36 heated manifold. New Weber carb running rich but acceptable. Adjusted up and down but still not happy as with SU. Not physically possible to run SU. Maybe DCOE?
DCOE can be difficult to stay in tune as well. But I went to an SU in my next build and am very happy with them. I have a video up driving an Amazon with a B20 big bore if you’d like to see more of the DCOEs in action. SU really is the best choice for simplicity and reliability. Adequate power delivery too, with a hot cam
Good reason to buy a genuine weber as well instead of a chinese knockoff. If it has a black electric choke its a knock off. There are other ways to tell but i have to wander how many of the people actually having issues are running a genuine weber carb.
I have a 32/36 weber that i purchase two years ago.
Only problem I'm having is the idle is too rich , like the exhaust gases will burn your eyes.
My 83 toyota 1.6 , the Weber is on came from the factory with primarily jet being a # 60 secondary # 50 .
Its running rich at idle and I've tried everything, advance the timing from the factory setting at 5° to almost 9°.
It runs great other than the idle.
Those are idle jet sizes and they are numbered backwards. You need to go to a 65 or 70 to lean it out.
I think the only difference between the DGV, DGEV, and DGAV is the choke. E is electric, A is water, and none is manual.
Can confirm, they're the exact same carb, just with different options for choke operation.
This is what I got after reading the EMPI site. Same carb; different choke options.
Hate the webers, and took it off my '62 P1800 as soon as I could. By chance, I came upon a set of DCOE 40's (pair) with the manifolds for a song (came off a 122) and ended up spending less than sourcing a set of SU's and having them rebuilt. Basically, you have other options than the original SU's, which are great, but not the end all be all of B18/B20 carbs. Look into sidedraft webers such as mine, and also the (albeit expensive) Mikuni carbs people are running.
sidedraft webers are my next inclination. I'm glad the 40s worked for your redblock. I'll start there
yeah ive heard nothing but good things with side drafts. simpler system, but not as fuel efficient.
Michael Peretto compared to the SU carbs or the downdraft weber?
ive also heard of folks running bike carbs like from an r1 and getting great throttle response.
Throttle response is great yes, BUT as daily it's not the easiest to drive I'd say. It's great for warmer weather.
ik this is a 4 years old comment.
yes I am running 4 bike carbs on my B21
Thanks for the information. I have 2xSU on a shelf but i think too buy Weber. Now i now NOT to buy Weber :)
+MattiasSweden 76 Its a B20 for my 142 :)
+MattiasSweden 76 The older I get, the more i realise it is best to keep the original parts to save headaches and problems later.
Emulsion tube air corrector secondary is too big, but also set ur float level. Their is a bulletin on corrected float bowl levels for DGV series carbs. Is it a real weber?
One thing i will explain is if you can hold constant throttle (under load) up a constant incline(4th gear say) eg. Hill type road for a few kilometres with consistent AFR 14 -13 you on the right track. If u want to increase you engine torque, ask you Camshaft shop for tow cam or torque Cam. If you use your stock camshaft and regrind
to reduce base circle, which gives u nice gain without breaking the bank. If u can find 4-2-1 headers, commonly known as extractors, also helps engine breath better and scavenge all exhaust gases = better atomisation of ur weber fuelling.
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www.pegasusautoracing.com/productdetails.asp?RecID=4127
Some good tips here.
they should pass a seat belt law
My amazon with 45 webers, starts to hesitate when it reaches 70mph. Starts to stutter and by then it wont run any faster than 50. Bloody annoying, cant seem to find the issue though.
Check fuel pressure. My car loses it at high rpm, so I then have to let it coast to let the pump catch up
Turned out the fuel hose from the fuel tank was in terrible condition. Car runs fine now, you were right didnt get enough fuel!
Congratulations! Sometimes it's really difficult to track down such problems
Soooooooo...
Weber cannot handle no more than 3psi of fuel, I think by not checking the floats and getting your hands dirty, you are really doing yourself an injustice. A jetting kit and a Sunday afternoon can teach you quite alot! Good luck
Will give it a shot. People say carburetors are simple, but for me it's hard for me to wrap my head around especially the vacuum and ignition stuff. At least I got my weber 32/36 for a decent price.
Why do a tuning video when you have zero idea what you are talking about? All you have done is repeat bad information from people on forums that don't know how to tune webers.
As a carb tuner for over 50 years I initially asked the same question but it is an easily accessible forum so thank you, David, for providing it.
Watched 1 19 23 Ok there to much to explain I’m working on 3 differnt webers chasing hp. Where do I get that thing that tells me to lean r rich. How much does it cost an I’m messing 3 centuries a 4,5 a4,0 a 3.5 I’m going down from a 4.5 to a 4.0 on a 40 Weber an a 38 Weber dgas they look about the same. Changing venturis going all the way to 3.5 wt is going to b the effects on jetting etc. I’ve made them both progressive also an ported polished both. I’ve got about 150 jets an 10 different imulison tubes. Trying this on big. Stroker vw buggy engines. I’m not new at this. Tips a bout the tubes jetting an Venturi size would b a blessing Thanks. I hope somebody tells me something. Bless uall