What Finish for Resurfaced Tappets?

After the dry mockup to check valve head clearances I will decide whether to go with flat tappets or 4" radius for the Web 312a cam. I'm leaning toward flat tappets for the added duration and reduced cylinder pressure at the bottom end.

Either way I need to have a fresh surface for cam break in. What is the proper surface finish and should they be machined perpendicular to the lobe rotation or in line with the rotation?

Dan1950 said:

What is the proper surface finish and should they be machined perpendicular to the lobe rotation or in line with the rotation?

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The tappets below were done inline with the cam rotation. Will be interesting to see what the machinists have to say.

Here's what was done in prehistoric times. Still ended up being a 100% flat surface where the 2S cam made contact. Somebody told me 600 grit sand paper was smooth enough.



Sorry to waste your bandwidth Dan. I wasn't doing anything else at the moment.