Valve shims: groovy and unkool

[JHertzman@xxxxxxx]

Colin Verrilli writes: 
"There are two alfa service bulletins (forget the numbers, but one is from
1983 and one from 1988) that say that you should never use the shims without
the groove in a V6 engine. What are peoples opinions on this? IAP only
sells the non-grooved ones and says that they are ok for both engine types"

Don't have the '88, but the '83 bulletin is certainly unambiguous that "due to
hardness specifications the 4 cylinder shims are not suitable for use in the
GTV-6 engine", and that one distinguished the two by the presence of a groove
on the six cylinder shims which may be used on either engine. I take this to
mean that the earlier shims were not hard enough for the new service, and that
Alfa started making harder shims which they differentiated by cutting the
groove. I assume they started using the new shims in new fours at the same
time; I doubt that Alfa continued making the softer shims just for the fours.

The IAP catalog does indeed list one type of shim for both engines, and says
they are "imported from Italy". I take this to mean that they are aftermarket
shims, and the question then is not whether shims displaying grooves are, ipso
facto, harder than shims without grooves. Or, does one trust that IAP's
aftermarket parts are good enough for their stated purpose? If I have full
faith in IAP's generic products (and if my faith is justified) they should be
fine, grooved or not. 

The problem is that if I have uncoded shims from the last ten old four-
cylinder tear-downs including pre-'83 cars, the next few tear-downs could
leave me with an undifferentiated assortment of hard and soft shims. But if I
only mess with sixes, (and with later Spiders, assuming that they use the hard
shims) and if IAP's shims are hard enough, it doesn't matter whether the shims
are grooved or not.

In the former case, if I might contaminate my $250 box of ungrooved hard IAP
shims with an occasional Alfetta tear-down, I would stick with Alfa shims. 

John H.

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