camshaft ?

[murf]

Hi guys, bear with me as im no mechanic !!
Van been running fine (82 Aircooled 2l cu)apart from when idling, almost feels that shes going to cut out, and struggles till I put my foot back on the pedal.
Thought it may have been something simple such as dirty carbs (almost new), or idle mix.
Took it to local place that specialises in carb tuning, had her on the rolling road last year and can recommend.
However, they couldnt find anything, mix fine, timing spot on etc.....but not firing on all 4, compression test ok but as they put it, firing on 3 and a half.
Apparently valves not depressing equally, and when one valve removed it made no difference to the engine running.
Their conclusion was that it needs further investigation but probably worn crankshaft, which can only get worse!
Sounds like this could get mega expensive....ideas?

cheers murf

[ghost123uk]

Sorry I cannot help much murf, but that does make an interesting read. Especially the bit were they removed a valve from the engine and it made no difference. It is also interesting that you recommend these folk

[BOXY]

I think this has lost a little bit in translation.

An engine can't fire on three and a half. A spark is either all or nothing.

They didn't take a valve out of the engine. They might have pulled off a plug lead. You do this one cylinder at a time to see if every plug is firing. If you pull a lead of a working plug the engine will run un-balanced. If you pull a lead off a mis-firing plug it won't make a difference. Taking a valve out would involve removing the head and lots of swearing.

Valves don't depress. They open and close. When and how long they open for is controlled by the camshaft profile and the rocker arm adjustment. Setting the valve timing is in the wiki.

If the valve timing is right and the lifters are working properly a valve seat might be the problem. I'd of thought the compression test would have high-lighted and problems in this area though.

Try and find a garage that knows how a VW engine works.

[murf]

Boxy thanks for that mate, these guys are purely carb tuners, not VW garage, and yes sorry one plug when pulled made no difference to the engine running.Will have to get her into a garage but you know how it is with these things, prepare for the worst and anything less is a result

murf

[murf]

just a thought, couldnt be something as ridiculously simple as a plug or lead?

murf

[jamesc76]

just a thought, couldnt be something as ridiculously simple as a plug or lead?

murf

Yes!!! change plugs, leads and rotor arm and cap, all perishable items and should be changed on major services!

[California Dreamin]

What he said ^^^^^^ Could be as simple as a duff lead or plug.

Martin

[murf]

doubt it will be that simple, plugs , dizzy, coil, filters etc, all fairly new but fingers crossed, will keep you posted guys


murf