Integrale 16v valve shim availability...

[Infectus-Guy]

Guy, i have a valve shim question that i'm hoping you can help me with.

I recently found that i had some pretty bad cam lobe wear on my integrale evo 1 engine. All but one of the inlet lobes were fine, but one had lost 3.5mm off its lobe height! The exhaust had about 4 with similar damage and others had scuffing. Not sure why it happened, oil pressure has always been good but the previous owner did snap a cambelt.
Despite lazy lobes it still somehow managed decent power but with (accidently) naughty boost levels that figure can be taken with a bucket-full of salt.

What i've done is got hold of a pair of good second hand cams, flipped the shims so that they're fresh face up (I assume its safe to actually run them like this) and taken some measurements - in imperial of course. (you know where i work afterall!) I made a shim diagram - the inlets seem just about ok (though i will have a swap around) but the exhausts are well out on 3 cylinders.

What do you suggest my plan of action now is? How accurately can i measure shims that have taken some stick? Will they have worn evenly out to the edge of the shim or might they have "bowled" in the middle making them hard to measure. Looks like i'll need 6 or so shims at the moment, are they easy to get hold of? Even if i get some that are too thick i can still take them into work and surface grind them, cheaper the better at the moment!
Thanks for any help you can give me,
Guy

[Guy Croft]

Certainly incorrect running clearance causes shim wear because the opening and closing ramps on the cam don't function properly. The load on the cam nose becomes very high and combinational scuffing and wear follows swifly. The stress distribution on a shim is such that the worst wear can occur in the center, resulting in a 'dished' effect.

Never take a chance on shim regrinding, use new. On this site I encourage members not to do 'cheap' - but to do 'right'. You'd need to know the hardnes depth to get away with it and of course the parallelism of one face to another is utterly critical.

I have good shim stocks, more than most, but from OE source the price, sorry, is very high, and varies with size. I don't buy OE shims..

Usually the causes of cam and shim wear are clearances or poor lubrication, the latter can easily result form overfuelling and oil contamination, viscosity loss in oil from running very high temp.

[Infectus-Guy]

I have a feeling clearnaces and temperature have probably played a large part with my cam problems. I see what you mean about the cam profile, it needs to meet the shim as progressively as possible rather than slap into it which happens with clearances being too open.
Can you supply shims? (i'll send an email i think!)
thank you,
Guy