I have a once-per- rev light ticking noise from the engine, hot or cold, idle or with some rpm added.....
Fifty years ago, it would be a dropped valve seat on the V12 .....hopefully something simpler, these days?

Thanks in advance 🙏

 

TooMany, I would start with a stethoscope and probe the engine. Put the metal rod end against various parts of the engine. See if you can narrow down where the noise is coming from. If you catch it early, you may be catching a roller for a lifter getting a flat spot and creating the noise. That may be an "easy" fix. If you want to throw something fairly inexpensive at the car to see if it may help, I would say to go to your local auto parts store and get a bottle of oil detergent. This stuff is added to all oil, but this would put a concentrated amount in. I would do it just before an oil change as it is going to scrub the inside of the engine and if you have any sludge, it is most likely going to break it free. But, it may get in and if you have something that is stuck, it may eat away what is binding it up and allow it to roll again. i would say to do this 20-50 miles before an oil change and do a few high RPM runs to really get things moving. Worst thing is you maybe did an oil change early. But, it could also clear up the tick. I have had mixed results on a few different engines with this product.

 

Thanks, Thermo 😊
On all the exploded diagrams l can find, the "valve stack" consists of a spring seat, spring, spring cap, 2 collets, a cam follower with a shim perched on top......
No mention of any rollers or lifters..... Am l missing something?

 

Toomany, the cam pushes against a plate that pushes the valve open. This normally has a roller built into it to reduce friction and prolong life.