Tappets

[Parksy]

Hi all


I have turned some tappets for the v4 engine using an unknown material that i had lying around the shed. My suspicions are that it was stainless, but it didn't appear to be a drawn rod, but ground. Does stainless come supplied as ground rod?

Is stainless a poor material to use as a tappet? If it work hardens from hammering, wouldn't this be a desirable characteristic?

My camshaft is drill rod and won't be hardened.

In the model engine world, am I worrying about nothing?

Thanks all

Andy

 

[gbritnell]

Because of the frictional load on the cam using 2 soft metals isn't a good idea. I make my cams from drill rod (unhardened) and make the lifters (tappets) from drill rod also but I harden and polish them.
gbritnell

 

[ruzzie]

Get the magnet out and give it a test.

 

[Foozer]

Makes sense - harden the lifter as the possibility of the cam warping by hardening is greater. With the light spring loads and a high zinc load lube the actual metal to metal wear is minimal . .

 

[stevehuckss396]

I make cams using O1 drill rod and make my lifters using 12L14 steel. V4 first ran in 2010 and both are still functioning with no wear. The only time I ever adjusted the valves is when I disassembled it for inspection bout 3 years ago.

 

[Parksy]

Thanks all for the replies. Didn't even think about the magnet trick. Tested them, non magnetic.

This would explain why they didn't harden much when I tried case hardening them.