What's going on with my valve clearances? (sanity check)

[alanr]

I agree things change on the twink head after it has been refitted and torqued down.
I have just had replacement guides and seats done on my cylinder head. I had got the shims spot on when I did them on the bench.
Using a standard copper Payen head Gasket I refitted the head today and after the head was torqued down I have had to change two shims on the inlet side and one shim on the exhaust to get the clearances correct.
I am expecting to have to redo them again after the engine has been run, retorqued the head, and things have bedded in.

Alan.

[paw140]

Bringing this old thread back! I am having issues shimming my 69 S4 (I posted a new thread as well on my issue) where the valves are so recessed in the head that the shims are too thin to be functional, and the tappet pad is hitting the spring retainer on one of my intake valves and cannot be adjusted with any gap. I saw some references to thinner tappets being available. Mine are the standard ones that are 0.22" thick and someone mentioned that thinners ones (0.16") are readily available. Who sells these?

[alan.barker]

Try fitting new Collets on the Inlet Valve and new Collet retainer that is touching. New Collets and new Collet retainer will move away from underside of Cam follower. Cheap try and easier than changing Valve Seat.
Alan

[paw140]

HI Alan,

Thanks for the idea. I saw this mentioned previously as well. Are there collets and retainers designed to sit a bit lower, or is the hope that I just get lucky? If they are designed to sit lower (I remember someone mentioning collets of slightly larger diameter), who sells these?

Thanks,

Paul

[alan.barker]

When i had this problem i could see the Collets were sitting too low. I bought some new Collets from Lotus Dealer and they were larger in dia. It fixed the problem.
Buy some new ones and try.
Alan

[Billmack]

I think as Tim says the problem is most likely the bottom side of the shim hitting the edge of the shim pocket. I remember seeing that thing with the tappet striking the retainer but not on a lotus, I had not worked on them til fairly recently. The other thing I can think of is there is crud on the seat and the valve is not returning to the same height because it is trapping crud between valve and seat. I would say also I have run engines with clearances in the ballpark but not right on the money and come back to them later to finish them off