Interesting Valve Clearance Technique

Carl H said:
One of the reasons I use feeling gauges to gauge accurately If there are changes in the adjustment I set them at after the retork of fresh engines. My jobs, the way I do things, don't change much, so that tells me everything is holding as It was set and there is no need to do any more retorks or worry about valve adjustments drastically changes. I get useful info from the feeler gauges within 1/2 thou, and I feel better gaining that info.
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Tornado said:
Had this viddy on my feed today...looks intriguing...

Basically the TPI of the adjusters is determined, then all clearance zero'd out with cam just about to open the valve...winding out adjuster by the needed amount previously determined, ie a partial turn. Set the lock nut and done. No feelers needed and it takes into account and valve tip indentations.
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Hobot used to swear by this method!
 
Tornado said:
But if you had a spare adjuster & nut in the parts bin, you'd only need to determine the TPI on the bench with a dial indicator or other method. Could even flat off the adjust top if worried about it. Once known, toss the dial indicator back in the bin and proceed as per video on the bike.
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Nortons and Triumphs use 32 tpi. Intake 1/16 turn (about .002} Exhaust 1/8 turn (just almost .004). That is for my 67 and my 68 Triumphs.
 
Tappet adjuster thread is 26 tpi not 32.

I have an ancient SPQR tappet setting tool. Very quick and easy to use. Sets clearance to within about 0.6 of a thou.

Incidentally, while looking through all the used valves from my 500 and 750 race engines I noticed from the tappet wear marks that all the valves most definitely do rotate when the engines run (with both standard and dual rate valve springs).
 
I use the "feeler gauge" technique. When I tighten the lock nut, and check the final result with a feeler gauge, I frequently note that the clearance has changed, usually tighter.
If you use the "no feeler gauge technique" proposed in this thread, how do you deal with this?
 
Stephen Hill said:
I use the "feeler gauge" technique. When I tighten the lock nut, and check the final result with a feeler gauge, I frequently note that the clearance has changed, usually tighter.
If you use the "no feeler gauge technique" proposed in this thread, how do you deal with this?
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You need to hold back the the adjuster to keep it from tightening as you tighten the locknut and it can take a bit of tweaking because of thread stretch to get it dead nuts
 
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Stephen Hill said:
I use the "feeler gauge" technique. When I tighten the lock nut, and check the final result with a feeler gauge, I frequently note that the clearance has changed, usually tighter.
If you use the "no feeler gauge technique" proposed in this thread, how do you deal with this?
Click to expand...

Is it looseness between the adjuster and the threaded hole in the rocker that concerns you?

With the locknut loose, you screw the adjuster down onto the valve, taking up the slack in the thread.

Unscrew the adjuster by 1/8 turn (or whatever figure you’re using).

Holding the adjuster in place, tighten the locknut. That again takes up the slack in the thread.

But you’re not “wrong” to do the job with feeler gauges.
 
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