Polishing of valve shims for a Fiat twin-cam engine

Polishing of valve shims for a Fiat twin-cam engine

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Stoatgobbler

Original Poster:

5 posts

85 months

Thursday 4th May 2017
quotequote all
Hi there, I'm a newbie on this site with a thirst for knowledge.

I fitted a Fiat twin-cam engine into my Morgan circa 10-12 years ago and have been shimming it by swapping shims or getting a local engineer friend to re-size existing shims, in all cases the shims I've fitted to my engine have their top surfaces (the side the cam rubs on) polished by the cam action.

Unfortunately my engineer friend no longer has the surface grinding equipment and I need a couple of shims which I don't have and so I've bought a couple of the right size from a company online. These are new shims and have a dull, I presume rust preventative, finish on both sides.

My question is:

A) should I fit these shims as is and lube well with engine oil before running the engine?
B) should I fit the shims as is and lube with moly grease and keep the engine revs up as in fitting a new cam / shim.
c) should I polish the top side of the shim and then fit it and then follow A) above?

Apologies if this seems a stupid question but I've been agonising over it for a week.

Stoat

Stoatgobbler

Original Poster:

5 posts

85 months

Tuesday 16th May 2017
quotequote all
Thanks folks, I've fitted them as they are.

Stoat