Misfire on 1&3

[burnzdog]

Good afternoon,

So still not fully satisfied with my 81 2L CU engine I have driven it over to Voodoovw for them to have a look. Chap got back to me today, and having balanced the twin ICT carbs, adjusted the timing to be correct he said there is a problem with cylinder 1 and 3. He did a compression test and all show OK. He also said he then swapped out the distributor but still the same problem. The ignition leads have been changed as have the spark plugs recently. I have also just installed a fuel pump and changed the oil.

Not sure where else to go with this. The bus runs but worried its going to need a new engine.


Any help appreciated.

[itchyfeet]

changed dizzy cap and rotor arm?
if defineately 1&3 different sides of engine suggests it's not carbs.

[ajsimmo]

Cam lobes? Only other thing I can think of that's common to 1&3. It may well test up alright on compression, but not breath well enough to actually fire properly. Check lift on rocker arms on all cylinders whilst turning engine over. Visual check should show this up if it is the problem.

[burnzdog]

Thanks for input, would that mean taking the rocker cover off and turning over the engine?

Cam lobes? Only other thing I can think of that's common to 1&3. It may well test up alright on compression, but not breath well enough to actually fire properly. Check lift on rocker arms on all cylinders whilst turning engine over. Visual check should show this up if it is the problem.

[ajsimmo]

Yep, exactly that. If you want to be more accurate, you can measure it using a DTI.

[itchyfeet]

Cam lobes? Only other thing I can think of that's common to 1&3. It may well test up alright on compression, but not breath well enough to actually fire properly. Check lift on rocker arms on all cylinders whilst turning engine over. Visual check should show this up if it is the problem.

I thought the same but thought how can lift be a problem if compression is OK ( I guess you are right low flow can still have high compression)
once case hardening has gone cam will degrade quickly but it would surely have to be very worn to be a major problem and then why just 1&3?
2&4 can't be much behind if this is the issue.

[burnzdog]

Yep, exactly that. If you want to be more accurate, you can measure it using a DTI.

Here's a slow down video of the near side head

https://drive.google.com/file/d/0B9jB4k ... p=drivesdk" onclick="window.open(this.href);return false;

I've swapped leads and plugs over. Engine still dies when pulling out plug 2 and plug 4

[burnzdog]

I'm at a loss with this chaps, not sure what else I can do other than get someone to look closer in the engine. I think it may need rebuilding to a certain extent. Can anyone guide me who to use and how much thisbmight cost?
I don't want to take it to the Vw garages round here.

Cam lobes? Only other thing I can think of that's common to 1&3. It may well test up alright on compression, but not breath well enough to actually fire properly. Check lift on rocker arms on all cylinders whilst turning engine over. Visual check should show this up if it is the problem.

I thought the same but thought how can lift be a problem if compression is OK ( I guess you are right low flow can still have high compression)
once case hardening has gone cam will degrade quickly but it would surely have to be very worn to be a major problem and then why just 1&3?
2&4 can't be much behind if this is the issue.

[itchyfeet]

I assume it runs so consider a trip to somebody who knows these engines and can do some tests you can't.
worth a phone call...
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