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had a guy out to tune my buggy today he reckons I have low compression on one cylinder possibly caused by a stuck or burnt out valve or possibly incorrect valve clearances.
Having just stripped this all down to replace the rings and all the associated gaskets, it will be easy enough to check the valve clearances, but if I have to go further and take the heads off will I have to change the cylinder head rings again or are they reusable?
I assume the pushrod tubes will have to come out again so will they have to have new seals? and obviously the rocker cover gaskets will need replacing.

If I have to take the heads off is there a quick way to test them to see which valve is leaking/sticking and is it worth having them machined and all the valves replaced?

Forgot to say it is a type 4 1700cc W code engine
If anyone has a set of spare heads kicking around let me know

Getting a bit fed up now as it seems to be one thing after another

Steve
 

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IIRC the sealing rings are no longer used.

Type 4 heads are notorious for dropping valve seats.

Befor you strip it down, unbolt the rocker shafts.
Hold a straightedge across the valve stem ends.
All the stems should be roughly the same "height".
If one is considerably different, the seat has dropped,
the valve has burned or stretched.

If you do remove the head, blow compressed air into the
intake and exhaust ports and coat the valve seats with
soapy water to disclose leaks.

Some helpful Type 4 articles here:
http://www.bostonengine.com/articles.html
and:
http://homepage.mac.com/ratwell/Type4/Menu87.html
and:
http://tunacan.net/t4/
and:
http://www.ratwell.com/
 

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The head rings come as part of the gasket kit 021 198 009 (A?).
I don't know where the popular myth came from saying that the rings were unnecessary. Vege machine their heads with a step, as do AMC; neither need the ring. All other heads do use the rings unless you want to add a bit of compression. I've had a few old units without rings where the barrel has not been seating against the head properly.

The water boxer has the same studs and the same type of rings, what is interesting is that the torque for the WBX head is 37ft lbs or 50MN for Johnny Foreigner.

Whatever route you take, lightly grind the barrel into the head to ensure that you have full sealing across the face.
 
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