[paul.spencer]

Yeah, they are shimmed. I'm looking at the document from TIS right now.

Looks pretty straight forward replacing the shims.

Prescribed value intake valve clearance 0.15mm; exhaust valve clearance 0.25mm.

 

[paul.spencer]

Shims wear down over time. The prescribed valve clearance value determined on the cold engine is done using a good old fashioned feeler gauge. You will probably find that the valve clearance is greater than the prescribed value so replace with the required shim.

They give an example calculation:

Thickness of removed shim A 3.15mm
+ measured value B 0.25mm
- prescribed value C -.15mm
------------------------------------------------
= thickness of new shim D 3.25mm

Any shims with values worn off should definitely be scrapped

I have seen a range of shims available on my old copy of EPC, you could prbably get them at Vauxhall parts or whatever

 

[paul.spencer]

sorry fire, you beat me to it while I was wasting time writing...