I got a problem!

[Dean...]

Hey everyone!

I haven't been online for a while. To those who I have made friends with and I haven't replied to emails, please forgive me. I haven't been well for a long time, but I'm starting to feel better.

My problem.... A couple days ago I went and started the car, but it felt like it was only running on 3 cylinders and when I revved it, it would backfire. I've always had a problem with the Weber on the right, so I thought that this was my chance to put on the other set that I have which are much better, so all good.

I had to pinch a couple parts from the Weber's which were on the car, and found that the person I paid to rebuild them installed the accelerator pump diaphragm on backwards! Anyways, I'm ready to install the better set, and thought I would do a compression test. The results: 1:130, 2:133, 3:153, 4:145. Obviously something is going on with the left side, so I'm about to check the clearance on the valves, and retest. Those tests are with the engine cold, and wide open accelerator obviously because I haven't installed the carbs yet. The picture that is attached are the plugs, one being on the left and 4 on the right. To me they don't look too bad, I was expecting one and two to look lean.

Some background.... The top end was rebuilt not long ago. I had the heads checked over by a VW specialist who installed new exhaust valves while he was at it. The carbs I've pulled off were twin IDF 40mm Weber's which will be replaced with twin 44mm Weber's.

The engine has for the most part ran cool all the time. I have noticed that the temps go up with I'm cruising at between 115-120 km/hr with the sump oil temp going up about 20-30 degrees Celsius. As soon as I drop the speed, so do the temps. BTW, the motor is 1916.

What do you all think? I'm kind of hoping that the valves on the right are a little tight, and that the compression will go up a bit when I regap them, but I am a little worried that they won't. After I do that I'll put some oil in the cylinders and see what the compression is then.

Everyone please cross your fingers!

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[Dean...]

Quick update...

I just finished checking the valves on cylinders one and two. NB: I have chromoly pushrods. I could spin all pushrods, but the lash on both exhaust valves was very small, I couldn't even get a .001 feeler gauge in. So I've increased the lash on the exhaust valves to match the inlet valves. I can get the .002 in but not the .003. Now to check cylinders 3 and 4.

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[Dean...]

I ended up taking the rockers off to check the bottom head studs. The I've beside cylinder one inlet was a little loose but the rest were fine. It's all back together now and I put a little oil in cylinder one and saw no increase in compression. I think I'm just going to put it all together and see how it goes.

In the process I found that the wheel nuts on one of the back wheels were loose, so I'm glad I went to all this trouble or I wouldn't have found this issue

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[Dean...]

Update : it's all back together and running, but not great. The mixture screw for cylinder 4 is all the way in, where as the others are somewhere around 3/4 out. Anyways, the idle jets in it are 52's, and I have 50's too so tomorrow morning I'll put them in and see how I go. When I'm revving the motor, so long as I don't do it quickly it revs fine, so maybe the smaller idle jets will help that too, and if not I'll have to adjust the accelerator pump.

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[Dean...]

I don't know what to do.... The right carb is running sweet, but I can't get the left one right. No matter what I do, the mixture screw on cylinder 4 is all the way in, and cylinder 3 is almost the same. I have no leaks at the manifold. I'm going to take them off and check that the butterflies are completely closed, but I did make sure if that before I put them on.

I gave them a really good clean. I cleaned them about 3 times in really hot water, almost boiling them on the BBQ. I just have no idea where to from here....

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[Dean...]

Time for me to get back at it again. One carb is installed, in the process now of making a gasket for the other side.

I plan to reset the tappets again as I noticed that they were extremely noisy, and groom what I've read of these chromoly pushrods, that as the engine heats up, the gap is only going to get bigger, and therefore louder.

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[Dean...]

Just for fun, here is a pic of where things are up to

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[Dean...]

All is back together now, but then I couldn't get it to start. Ended up finding out that the coil had all of a sudden decided to die. I went and bought a GT40 but when I got home and tested it, the secondary circuit showed around 15000 ohms, so I'll be taking that back tomorrow. Luckily I have a habit of keeping crap, and found an oil coil which tested well, and after installing it the engine fired up!

I can't get cylinder 4 to fire. I can hear it fire every now and then, so my guess is that the plug needs to be cleaned. Right now I'm waiting for the motor to cool and then I'll proceed to fix that problem.

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[Dean...]

I knew I should have cleaned the plugs while the manifolds were removed!! Cylinders 3 and 4 are running great, but I can't get the other two to do the same. My guess is the plugs are fouled. It's getting late here in Australia so I'm going to finish up early for a change, and get back to it in the morning. I forgot to reset the tappets, so now I can do them first thing tomorrow, then clean the plugs and I reckon, fingers crossed, I'll be able to tune these carbs!

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[Dean...]

The fun continues....

This morning I cleaned a couple plugs and reset the tappets. The engine is running, but it's running too fast now, and I can't get it to slow down. My understanding is the time to adjust the mixture is when the engine is idling below 1000 rpm, but it is idling at over 1200. The right carb I could slow down, but the left is screwed all the way in and it's sucking around 7 on the snail gauge. My guess is that the butterflies aren't closed enough, but I checked this when I cleaned then up...



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[Dean...]

This will be my last post. I really have no idea what to do to fix my car, and I was really hoping that someone would try to help me, but I guess I'm just too stupid to help.

All I wanted was a little help. I know that there are some smart people here, so the only reason I can come up with for the lack of assistance is me.

To those who did read my story, if in fact anyone actually did, I'm sorry I wasted you time. It will never happen again. So here's me, signing off.

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[Chip Birks]

I wish I could help. I just built an engine with IDFs and couldn't sell the car and get it out of my life fast enough. Everytime i drove the car it plugged a jet.
Unfortunately there are maybe a dozen people actively using this forum right now. I am an EFI guy. I couldn't keep IDFs happy either. Sorry we hurt your feelings.

[Ol'fogasaurus]

Dean, I'm running a pair of 40 Dels which I bought from someone who was into VWs. He warned me that he had problems with the left carb wanting to have the idling system/circuit wanting to plug which has happened to me several times (I think it is or one side of the engine has a bad plug or spark plug wire). Periodically I pull the carb, spray carb cleaning through all the jets and casted in air of fuel areas then, when things are re-put back to the specs properly, the problem goes away... in my case; for a while.

I have had other carbs over the years with similar problems and I agree, it is very frustrating.

Also check the gaskets and mating surfaces between the carb, mount and heads for an air leak.

Lee