Hi all, How thin can the valve shims go? I'm in the process of reassembling my 1600 head after having the valve seats and the valves ground (new guides and resurface also). The work was done at an experienced alfa shop. The seats were cut/ground with a 3 angles and did not go below the chamber surface. And I don't think much material was taken off the intake valves (maybe should have just gone with new ones!). The exhaust cam went in with shim thickness within normal range (.060 to .080). On the intake side the shims are on the thin side with one shim calculated to be around 0.042", less than what's available. The cam is a 10548 euro cam. Looking at what available for minimum shim thickness is see 1.5mm (0.059") as the minimum list (two major US suppliers).
Does anyone have experience with going "under size" on the shims. At some point I guess the shim may end up failing/crack? Also grinding the shim down would need to keep the surfaces parallel and the question of hardness would need to be considered. Can the shims be annealed (heated cherry red with a slow cool) and then after grinding re-hardened (heat cherry red with a quench). Anyone know the Rockwell hardness on these? I've put the head on the block with the new head gasket but have only torqued the nuts to 15 ft-lbs (BTW - I found my lost nut). If I need to remove the head and put new valves in how bad would it be to try and reuse the gasket? Thanks and Happy Roads, Al 1967 Duetto (in complete resoration) -- to be removed from alfa, see http://www.digest.net/bin/digest-subs.cgi or email "unsubscribe alfa" to [email protected]
