8BA valve retainers

[GOSFAST]

The rotation can be powered by multiple things in an engine, the lifters in a flat tappet setup rotate and compressing a spring gives you a rotating movement.
So no need for a mechanical devise in the rotator to create movement just a "slipping" function to let it move.

While I agree with one part above, I believe the lifters don't really participate in the valves rotating. I MAY be incorrect here but let me explain why.

If you take a Chevy as an example, where the valves are "disconnected" totally for the spinning action of the lifters, they still manage to rotate with the "conventional" mechanical rotator's under or over the springs. The pushrods are the only parts caused to rotate from the spinning action of the lifters in that scenario.

I do understand the valves are directly connected to the lifters on the Flattie's but I believe it has little to no effect on the spinning? Again, I'm only guessing here!

I do believe in BOTH cases the spring's to be the root cause of the valve's rotation?

Thanks, Gary in N.Y.

P.S. On many of G.M.'s models, there are some with the rotators only on the exhaust's and others are on all 16 (Oldsmobile's come to mind here). Some are below the springs and some are above! (I don't care for the above setup at all due to the add'l weight of the parts on top, makes the spring work harder and would require slightly add'l pressures). Pontiac for instance never used them at all (at least that I recall)! I believe the spring action will "force" the valves to rotate whether or not they are even present? Once more, I'm just guessing on all this here, sounds logical!

 

[flatheadmurre]

The tappet rotation does matter, works same for an OHV engine.
Look at the rocker arms they are offset compared to the valvestem to.
Not sure if all know why the rotation is good ?
The rotation gives you a uniform heating of the valve and seat which prevent thermal distorsion.
And the rotation takes away deposits and soot from the exhaust going out maintaining a good seal for the valve.
If you have heavier valves with more mass that is harder to get moving you need a mechanical setup to rotate the valve (rotocap, rotomat, or as in big diesel a propeller on the valve stem)