And it just keeps on ticking....

I think I know what I should do, but I sure would appreciate some advice on this one –

The valve below came from my ’74 Roadster, it was ‘resting’ from ’82 ‘til ’08. After resurrection per Fred Eaton’s’ check list, it had a minor ‘tick’, seemed to come from the drive side exhaust. Figuring a fatigued spring might be the culprit (26 years possibly at full compression?), I pulled the head and this is what the top of the valve looked like:



Still thinking fatigued spring, I went all in, with new guides, valves, springs, and mushroom adjusters. Guide & seat machine work done by a local guy with an excellent reputation.

Got it back together, and I still have the ‘tick’. Damn. Set the clearance to a “tight” 0.008, and it keeps on ticking. Double damn.

Soooo, I read a bunch of past posts on geometry. Stared at the engine awhile. Stared at the old valve awhile.
Looked at the adjuster/valve contact point with the new stuff, looks the same as the old stuff. So does the scrub path.
Measured the extension of all four adjusters in the rocker arms, and this one is .028” higher, meaning the rocker is closer to the valve stem than the other three.

After all that, I’m thinking I probably need to take about 0.012-.0.014” off of each end of the pushrod. Does it sound like I'm going the right way with this, or should I be looking at something else before cutting metal?

Great photo, very nice close-up.

The key to correct rocker geometry is the installed height of the valve stem; each time a seat is cut the vlave gets a bit higher. This can be influenced by the amount your barrel and head are machined to be flat, as well.

Don't forget that the rocker arms have a 1:1.13 ratio, meaning that for every inch the cam pushes up, the valves get 1.13" of opening (not that you'd ever see such a stretch). If you choose to shorten a pushrod keep that ratio in mind.

Get yourself a set of the "mushroom adjusters", they slip acorss the valve stems with reduced friction.

Al that said, back in 1970 I took my brand new Triumph Bonniville back to the dealer and told them that the upper end was making way too much noise, they told me "bring it back if it stops making noise"!

RS

Now that you've gone this far, it's not worth it... However, Porsche swivel-foot adjusters won't gall valve stems. Ever.

broken link removed

I had to drill and tap my rockers to install them, so they're more like a 3.5 on the 1 to 5 garage-junkie scale. On the plus side, its a perfect excuse to spend some time lightening your rockers.


My valvetrain, however, is still pretty loud at spot-on lash settings.

looking at your valve the rocker is stricking the valve from one side, you may also have to shorten the valve,a dummy push rod for checking is a better option than shortening all yours and finding its doesnt fix your geometry and it will probably not make it any quiter,check to make sure your push rods are straight,if all else fails buy a good fullface helmet

Do yourself a favor and also check the cam lobes while you have the cylinders off. If a tappet is hanging up on the ridge of a worn lobe you'll get some very strange noises. Ask me how I know this...

Thanks all, for the advice!

I completely spaced the installed height measurement, doh! That would be important, wouldn't it
Is there a target for the valve stem height? I looked in my Chilton's and the factory manuals, but don't see anything. I can compare the noisy one to the other three and see what I learn there, too. I'll pull the head tonight and try

Dr. H, those are some trick rockers you've made! If I can find a set of rockers cheep somewhere, I might be tempted.

And if I can't come up with anything else, that full-face helmet option is still on the table....