TheSamba.com :: View topic - 32/36 not idling right after removing top.

Tue Jul 13, 2010 12:14 am

I would put the smallest main and idel on the primary side with the biggest air.. make sure that Oring is on both idels, alot of carbs don't have those orings, people don't know it's there and loose it look up som eof the Aussie off road sites, There's lots of people using that same carb over there,, not just on VW's.. my kid has the same carb on his 4.2 6 cyl jeep Those carbs will flow one hell of a lot of air.

I think you said it came from a 2.3 motor ??? so it way over jetted for a 1700

FYI, there one other carb ( weber) called a 38/38 outlaw,, The same carb with both vents at 38 mm and a real two barrel, not progressive... but they look the same ... Those are a Hot little carb

Tue Jul 13, 2010 3:22 am

towd:

The carb was possibly from a 2.0L Ford, and my motor is 1800, so not a massive difference but still one to be bridged.

besides that I got the carb with the rest of the kit. The kit was one someone had but didn't use so he didn't know.

I swapped the idle jets but haven't swapped the airs yet as I put the carb back on before I saw your reply.

My findings:

After priming the carb, the engine started quickly.

Remember the spark plugs are carbon fouled from the previous issue.
The plugs started coming to life and firing better within seconds, which I take to be a good sign of it not running insanely rich. I still need to replace the plugs.

I waited for the fast idle to drop back. It did a little, but it was still running at nearly 1500rpm, so I backed off the idle screw. And backed it off more, and more until it could back off no more. That got it down to maybe 900RPM.
All i could think is either vac leak or ...? Idle jet gone from chokingly large to a bit too big combined with lower float level? I dunno.
While this is going on the vacuum is holding steady at a bit over 16"Hg which is honestly the highest manifold vacuum i have ever seen on that motor under those circumstances. It wasn't pulsating.
What I will try to do is run it for a while, let it cool and check the plugs. Odds are it is still a little rich, so the whitest plug wins if there is a runner / manifold leak. Otherwise it could be a carb base gasket leak. It has one of those rubbery ones currently. But with that vacuum I have to wonder if it is a vac leak. It just didn't feel quite like one.

If someone has any suggestions on other jets I'll order them and a base gasket at the same time as they both have to come from the same place.

The exhaust didn't smell so vile either. There was a tinge of the unburned from the ailing plugs, but the choking sooty smoke seemed to be gone.

So, a generally positive result.

Tue Jul 13, 2010 5:09 pm

Two other things I forgot to mention.

There are no O rings anywhere to be found on the idle jets. But i also see nowhere they can be fitted. Different design perhaps, as the bolts that the jets push into don't actually screw in all the way, and the thread goes all the way to the head of the bolt with no flat / recess for an O ring. Not that it would screw in far enough anyway.

Something else I noticed. Totally forgot about this one. I think the exhaust temperature is hotter which makes sense. I noticed because it was a cold and wet evening. After I had the motor running for a couple pf minutes I stuck my head in the cabin to check on everything and noticed a warm breeze. the heater was putting out warm air a lot faster than it usually does.

I haven't swapped the air correction jets yet.

My bays motor may never run great again, and personally I think it's life may be limited. Still, I do what I can.
When it dropped a valve seat in '04 I found that the rebuild the PO apparently had done was not so hot. Cooling fins clogged solid with solidified oil muck. an almost full complement of broken rings, badly done spark plug helicoils etc. It just went on.

The motor is now a lot cleaner than it used to be, gets good compression, doesn't leak (much) etc. but what horrors lurk in the bottom end I don't know.
There isn't any metal in the oil when I pull the dipstick, so it has one up on a couple of our previous daily drivers but yeah.

I never lugged it or drove it at 100MPH ;) Actually I barely ever took it over 80km/h (50MPH), so it's not like I mercilessly beat on it. But still, wear and POs.

Tue Jul 13, 2010 5:51 pm

good your on the right track..

The jets I mentioned last night. that carbs was not a 2000. closed cnamber head eqauls hot rod head hi compression ... it also had a small cam headers some trick intake manifold... But the jets were smaller..
I'm 125 above sea level. I could check others, I have atleast 7 or 8 webers of that style laying around LOL.

Many people don't understand a carb runs on the idel jet until mid range,, only then does the main circut take over, as soon as you let off the gas, it goes back to the idel circut..

on these carbs I don't understand why they even have an idel on the sec, circut, That also comes in mid range

if I remember right your are about 18 hrs difference from the west coast USA.. if you want ( my Time) tonight I can take photo's of this idel jet Oring.. and the jet holder ..

I'll look I think I have one we used on a vw, but it would have been ona T1 engine

Tue Jul 13, 2010 5:54 pm

Thanks, I'd appreciate it. There must be some difference between jet holders. Either that or they have a massively fat O ring like a doughnut.

Been meaning to take a proper shot of my carb. It'll be with top on but it gives an idea of the variant I'm deaking with.

Tue Jul 13, 2010 7:41 pm

Checked the jet holders on several different Weber DFV and Holley 5200 carbs, none had o-rings, none have o-rings on the mixture screws either. Unlike a dual Weber IDF, the progressive will transition to the main system at even a high idle, it is always on the main system under load. When you rev it up and see fuel spraying from the main feed tube into the venturis, it is on the mains.

I wrote down the out of the box jetting for a Holley 5200 aftermarket carb with a dual booster venturi on the primary side, this is not a carb I have ever run on any engine. Note the fairly square jetting:

....................Primary.............Secondary.......

Main jet ......... 114 ................. 127.......
Main air bleed . 175 ................. 195 ......
Idle jet ............ 60 ................... 70 ......
Pump shooter ... 07

I have a new out of the box aftermarket Weber DFV, but have never checked the jet sizes.

Tue Jul 13, 2010 9:35 pm

o show n tell time...

These are the two types I have I counted 10 on the shelf .. in every photo.. DGAV on the left ,, DFAV on the right.. the quick ID is DGAV retangulur top, large air horns.. DFAV oval top smaller horns ,, closer look you'll see the mirror image of each other,, pir and sec's are oppsite as are the acc pump..

This one just show there bottoms you can see pri and sec's are opposite

also the linkage

Here's the interesting part, as said I don't know shit according the vW tech.

oh well.. look in the hole as with most webers the idel jet O ring will either stay in the hole or fall out and get lost, you can see the black O ring in is place
This carb is the DGAV, I check 6 each has a Oring

now it get better, the no shit I didn't know.. this one is a DFAV ,, there's no Oring no groove for the Oring, never was or well be.
hope these aint backwards, can't see them there to small..

the jet in there holders,, FYI there two piece, the screw thing is call a holder, the tip / jet comes out .. same deal on the left and right..

on the left near the top. you can see ( I hope) a groove for the O ring also the head/top is thicher, right no groove, the thread go all theway to the top, top is thinner

This one I dug the O ring out and stuck on there just for show n tell..

I didn't take any other jets out this DGAV had 60 pri and 50 sec ,, the DFAV had 50 pri and 60 sec. I check one other DFAV, that has 55 pri 50 sec

as I said last night I've seem motorcraft .. holley weber and weber names on these.. I did read that some say nothing but inside the bowl is holley weber, never seen that... on eveyone of these the DGAV hqave weber on top and the ACC pump cover. on the DFAV the only place weber can be found is the ACC pump cover, nothing on the body or inside ( ??? ) The DFAV is the common carb used on VW's , because of the side the linkage is on

I've alway found the DGAV to be easier to tune, only using those on VW's you have to wacth what type intake manifold you have and which way you mount the carb, I've seen people put these on twin port intakes, mount so the linkage fits a VW cable and wonder why they don't have any throtlle, They'll say I can only push it down half way ..

gee I wonder why ?

Tue Jul 13, 2010 9:54 pm

you were talking about the black rubbery thing under the carb,, I think you said thing ,, it's a isulator, used to stop the heat from the intake manifold, going to the carb. on water cooled motors without this, the fuel in the float bowl can boil. on your VW don't use it, you want the heat. and if you think your mounting gasket is shot just make a new one.. shoe box paper works very good, I save all the boxes gasket come in, the flat type thich paper,, do use sealer,, grease your gaskets. grease works as a sealer, best part most of thetime by using grease you will be able to reuse the gasket.. should you make gaskets match those to the intake, not the carb base.. to make a gasket just lay the paper on the manifold, use a small hammer and tap along the outline, keep tapping and that will cut out the shape, if it's something you need to woory about being damage just tap lightly to copy the shape, then cut it out.. You can buy hole punches or you can find pieces of tubing the size needed, sharpen the edge, you have a punch, these work best when backed up with a very hard plastic, which saves your sharp edge, next use steel, these two will give you a nice round hole, if you use wood you will have a ragged edge on the hole..

Tue Jul 13, 2010 10:11 pm

once you get this drivable you may get the OL carb iceing,, wild has a cure for that...

Here's something I've done, only because some one else did this and it worked, but again on a T1 and both these used a SU on a turbo.

For these reason I can only question what you hear about theoutside temps. I've had iceing all times of year on unheated and heated intakes

ok with a turbo your pushing ( ??) 10 times the amount of air at 10 times the speed using a draw system, if on boost for very long the entire intake and cold side of the turbo will turn to ice, not just the frost a normal system gets..

this guy had taken his oil feed line to the turbo ( cooper line) and wrapped the intake with the feed line ( warm oil heating). using a turbo you get the oil via a tee at the oil sender, of course you need a return, cooper line is spendy. I coypied what he did and it works..

Tue Jul 13, 2010 10:17 pm

lots of info there!

I took a photo but forgot to bring the camera in with me.

My DFAV looks a little different to that, but that's to be expected.
My top casting is different but I'm guessing roughly equivalent functionally.

So, no O ring on DFAV idle jets?

My carb setup is slightly different to what most do. My carb is "backwards". Ie I can get at all the adjustments easily, and my accelerator cable is on the right. I relocated the accelerator pedal tube to the right, fed the cable through a hole in the transmission carrier and it goes into the bay through the tin via a brass pipe fitting (I think it was a size adapter. I just know it had a nice funnel profile inside) to prevent any scuffing.
So I have a direct linkage and as a result my carb throttle lever is above the butterfly shaft. No interference issues or fiddly mechanical linkages to worry about.

Where was I...

I swapped the air corrector jets. Was there a difference? I don't know. I am still baffled by it's dual idle speed though.
It'll chug along at 1500rpm, then just drop to about 900, and eventually suddenly jump back up.

The vacuum is still holding steady between 14 and 16"Hg the whole time, so I doubt it's the power valve wreaking havoc.

I let it run for a while today so I can check the plugs.

:(

When it was warmed up, I played with the idle speed screw to get the idle down.
That was interesting. There seems to be no midpoint between the high idle and roughly normal idle range. It also started blowing smoke from the exhaust. I would have said vacuum leak, but the mix seemed rich and the vacuum is strong. When the engine is stone cold again I'll pull the plugs for a post mortem

Oh yeah, when I got the revs down it was banging and carrying on from the exhaust. Hmm.

Tue Jul 13, 2010 10:49 pm

ya it looks like the DFAV's don't use the O ring..

That spacer you have under the carb, This Baja has a 3.8 and uses that spacer under it's carb, I had problems with it smoking and the rpms going up and down, turns out that block had a crack, which is common on cars using those, people over tighten the mounting nuts.
This is another one of my don't know shit cars... I tell ya, I'm one dumb mo fo

Like this one, just put the canvas up this this after noon, it only took me tens days to make the pattern, ansd sew this thing up, alone ! it made for a 30 year old tent and double tickness.. sometime I wonder how I manage to wipe my own ass Alone ??
but then if a guy has 15 vw's and there all the same type he knows it all

every VW Ihave is different .. LOL damn boring to own 15 chicks and are all 300 lbs

Wed Jul 14, 2010 1:39 am

Damn, you snuck in two posts before I sent mine! Just saw them.

OK, so get rid of the rubber insulator. Can do. I have some nice thick gasket paper I made the intake manifold gaskets out of.

I actually thought of putting an oil line around the runners, but i hadn't heard of anyone else doing it.

I read all your posts and took them in. My %$*& back is killing me right now so I'm thinking a bit foggy.

Went through the plugs. Poss. leak at #4 (I hope. That's the corner I want to check out next time I pull the motor).

#4, well it was either firing damn fine or not at all. The plug looked a lot like it did after I wiped the crap off it last time, so I chucked one of my horrible rusty old Lucas plugs in. Yeah I'm out of plugs. Actually had a couple of NGKs go open circuit on me.

Beside the point.

I gave the manifold nuts a slight tweak / test and fired it up again. Running on all 4 mostly. A fair bit of popping from the exhaust at lower RPMs. Perhaps intermittent firing from a crap plug?

Still running for a while at one speed then suddenly shifting to the other, then eventually back. If it is a vac leak it's a weird one. Usually the revs drift.

At it's low idle the motor kind of reminded me of one of those old exhaust valve governed industrial motors. I forget the name. because the exhaust was kind of going quiet then loud as if it was hitting its target speed then cutting the juice until it dropped again.

After a while of doing that the motor just kind of goes "Screw this!" and winds itself up to 1500RPM effortlessly and sits there, running nice and smooth.

I'm really at a loss. I'll try making a base gasket next, after I check the plugs again that is.

Don't remember if I said but compression on all 4 is good, if a bit uneven.

Wed Jul 14, 2010 1:58 am

I am thinking its a vacuum leak still. Maybe when you installed your manifolds to the heads one of them didn't seat properly. They are pretty crabby after all. It is possible on some engines to catch a corner of the engine tin under the manifold flange, I have had to cut or grind the tin back to avoid doing this. With the progressive you want to be using the thin metal gaskets between the head and the manifold, not the thick insulating gaskets as used on the FI engines. I have wondered about using a thin smear of silicone instead of the metal gaskets. This might let more heat pass through and might seal better if the flange was warped.

Wed Jul 14, 2010 2:45 am

Wildthings wrote: I am thinking its a vacuum leak still. Maybe when you installed your manifolds to the head one of them didn't seat properly. They are pretty crabby after all. It is possible on some engines to catch a corner of the engine tin under the manifold flange, I have had to cut or grind the tin back to avoid doing this. With the progressive you want to be using the thin metal gaskets between the head and the manifold, not the thick insulating gaskets as used on the FI engines. I have wondered about using a thin smear of silicone instead of the metal gaskets. This might let more heat pass through and might seal better if the flange was warped.

that's the thing. Why would this leak have appeared while I'm doing this? I have no reason to touch the runners while I'm removing / installing the carb.

I'm not saying that it isn't a leak. I just don't know why it would have started suddenly.

Is that what FI busses use? I'm using paper gaskets I made. I had terrible sealing issues with metal gaskets. Possibly because of the way the tubes are attached to the manifold plates. they are welded from the inside IIRC. I'm just guessing though.

They sealed with the paper gaskets so I didn't touch them. I guess I should pull them again to check.

The gaskets I made are the same shape as the runners. One piece things.
One thing to note is my runners fit both type4 and 914 3 stud heads.

When I got the setup I sanded the plates flat with glass and fine wet & dry sandpaper, although they were already pretty good.
I haven't disturbed the gaskets since the last time I replaced that head and went through gasket capers. had no reason to. I think I put them on dry.

I tried silicon. A few types of gasket sludge to be honest. The results were varied but not fantastic.

When the heads warm up I still get heat transfer. It may not be super amazing but it is there. I don't know. If I can find a price for the metal gaskets that isn't horrifically bad I wouldn't mind trying again.

Wed Jul 14, 2010 3:04 am

There just aren't too many places for a progressive system to leak, especially a leak that primarily affects only one cylinder. You can pretty much only have a leak either at the head or have one of the boots between the runners and the center section leaking. Most any other leak should affect all the cylinders fairly equally.

Wed Jul 14, 2010 3:56 am

Absolutely. I wrote off #2 as a dead plug. #3 was black with a dark corona around the electrode where it had burned off the carbon.

So now I've run it a bit more I will have another look hopefully tomorrow at the results.
The lack of flutter on the vac gauge is curious though. I have seen massive flutter with port based vacuum leaks that affect the revs less. Another strange thing is that in the past I have been lucky to get maybe 8 or 10"Hg at idle. How come I'm getting better vacuum? What should it normally be?

Wed Jul 14, 2010 8:26 am

RatCamper wrote: Absolutely. I wrote off #2 as a dead plug. #3 was black with a dark corona around the electrode where it had burned off the carbon.

So now I've run it a bit more I will have another look hopefully tomorrow at the results.
The lack of flutter on the vac gauge is curious though. I have seen massive flutter with port based vacuum leaks that affect the revs less. Another strange thing is that in the past I have been lucky to get maybe 8 or 10"Hg at idle. How come I'm getting better vacuum? What should it normally be?

A vacuum leak will not necessarily cause flutter or much of a change in vacuum, though it certainly can.

Doubt that is it your problem, but I had a horrible idle and mixture problem on my '83 1/2 when I bought it six'ish years ago. It seemed to be running rich and lean at the same time and was driving me nuts. I tried everything I could think of the find the problem with no success, but on finally removing the manifold I found that some previous mechanic had left a socket laying in the intake port. This was a FI'd engine and it just whacked out the flow through the AFM causing the mixture to jump all over the place.

Wed Jul 14, 2010 9:38 am

your going to have to do something about the plugs. OMG Lucas plugs, LOL. I've had one set of those in my life time.

do you have any way tosand blast ? or a compressor and blow gun. with the rightsize T fitting and some hose you can turn a blow gun into a blaster. once a plug fouls it will keep fouling deep inside. alos go out at night run the engine and watch for spraks jumping off the wires.. pull the rubber seals up away from the cyl covers see if you can look down in by the plug and watch for spraks down in there ..

I've never had a problem with the power valve on these, but on holley four barrels, one back fire can blow the valve out

your gauge bouncing around, but now it hold steady,, I get the feeling this motor is old, close to it's lastdays, been sitting awhile.. it could be therings are weak, the valve seats are the the best,, when you started getting it running each cyl wasn't pulling the same amount of air, now that it's beenheated up afew time those have reseated and the air flow has equaled out..

have you checked compression

Wed Jul 14, 2010 4:44 pm

Pretty sure I don't have a socket rattling around in there :) but I do get your point about vac leaks, Wildthings.

Those Lucas plugs are rare NOS parts. Worth a fortune! hah. I found them under the drivers seat with boxes and the little plastic sheath things. Never been used. Probably with good reason.

I have no access to a sand blaster, but I like the T fitting idea. But then what media would I use with it?
It'd probably be a fair drive to get blasting media, so it'd probably just work out cheaper to do the same drive to get more plugs.

My gauge had a good flutter to it when I first put the runners on. Before I found a gasket that worked for me. After that point, steady vac and evenly fouled plugs.

The motor has never sat for more than a few months. The rings are essentially new.

Compression is a bit uneven, although I'm wondering if the result was thrown off by my leaky needle valve problem, or possibly even carbon buildup.

This was on a dead cold engine. Done when I still had the flooding problem.

1-147
2-139
3-130
4-158

Don't know if I can get away with running it at night without someone getting upset at me. I guess arcing at the plug is a possibility. The leads shouldn't be. They are new too.

Wed Jul 14, 2010 7:29 pm

for blasting media, and I picked this up from someone else, it works,, regular old baking soda.. then those cheap air guns whatever you call them, unscrew the tip, screw in a Tee, then a hose barb on each end, then a piece of tube, like fuel line on the bottom nipple to the soda, the other barb acts like a nozzle..
This is blasting carbs, never tried it on plugs, can't see why it would work just blow the plug off really good, In the old days you could get a machine made just for cleaning plugs, they use fine sand. you can use anything , Hell you could use water, if you could get enough pressure behind it ..

More show.
see the spring do you have that ? it is one of the return springs, there also a coil on the shaft this one kepts
when it revs up, I guessing it stay there on open air buggys, the linkage at the sec will get wet, when wet it collects dirt or sand and will hold the sec open just a hair, if that spring get knocked off the sec will also hang open.. I would think that if the was very much sloopy in the slot a hi vacumn could pull the sec open on the right side of the sec linkage there's a brass nub ( ?) this is an adjustment screw..

heres that screw from a bottom veiw