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Triumph TR6 - Valve/cam adjustement non steady

Hello,

I am facing a strange problem. I adjust valves and after few ninutes of engine running some valves/tappets do not retain their adjustment. The problem is not at adjusting screws level as they are still lock. I imagine there is a trouble at cam level or follower. How could I check easily and find the problem? Any ideas what is in trouble?

Thanks all,

JGC
J. G. Catford

JG

You might want to check for wear on the rocker arm rod. You will have to remove the arm and remove all the rockers. The TR6 did have problem with poor lubrication and the rocker arms wear the rod. I know when I rebuilt my engine, I had to replace the rod due to this wear.

Other wise are you doing the adjustment when the lift rod is at its lowest point? Are you doing it when the engine is cold? Are you adjusting to 0.010 inches?After tightening the nuts are you checking again to make sure in tightening the nuts you didn't move the ball pin?

Make sure the rocker arm rod is bolted tight.

If the above is OK, then I would look at the lift tappets. If they are oK, then you need to pull the camshaft and that requires pulling out the rad and taking off the timing chain cover. Once that is done, you can check for play in the camshaft and pull it out if you need to. There is an archive subject on pulling the cam while the engine is in place.

Others may have better advice.

Good luck

Mike Petryschuk
Michael Petryschuk

Hi Michael,

I did not told the whole story. Problems occured after a head rebuilt with some new valves guides. After a 5 min run-in 2 valves seized in guides (steel original). The machine shop guy told me he never saw that and reamed guides. It is after that event I had problems. I imagine I must, as you mentioned remove camshaft for inspection. May be there is some cam or follower damage.

Thanks,

JGC
J. G. Catford

JG-My guess is that the pushrods bent slightly when the valves seized in the guides, maybe rolling them over a flat surface would verify the straightness.
Berry Price
BTP Price

When checking pushrods, roll them on a mirror. The mirror image will double any difference, making it much easier to spot.
Tom
Tom Sotomayor

I agree. The push rods need to be checked.

If the valve guide was reamed too much there may be too much play in the guide as well. There is a procedure for determining that in the Haynes manual.

I am not sure the cam itself would be a problem. If the valves siezed, the push rods or tappets would probably distort before the cam.
Michael Petryschuk

THANKS ALL,

I will check them on first instance. Too bad as I bought lightweight pushrod from TRF and I thought it was a plus...

Cheers,

JGC
J. G. Catford

This thread was discussed between 15/12/2007 and 18/12/2007

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