I think I finally found the source of ticking sound coming from the heads. This sound makes the engine sound like a tractor. The ticking is most audible at lower RPMs. By 3k RPM, you pretty mcuh don't hear it anymore.
The rocker arms I am using can contact the valve springs when the valve is completely closed. These rocker arms are not actually for a V4. They are from a V6. Jack Lawrence cut the entire V6 rocker arm assembly down so that it would work on a V4. That allowed me to replace my rocker assemblies after they got destroyed due to lack of oil. The new arms however have a different design.
One of those differences is apparently pretty important. The original rocker arms all have a part machined out to make space for the spring. Its like a line cut straight across the rocker arm collar or whatever you call that part. The new rocker arms have no such machining. This is where the springs hit the rocker arms.
I will have a machine shop modify my new rocker arms to match the old ones and see if that cures my ticking noise issue. I am very confident that it will. It would be great to have a quieter engine again.
I machined the rocker arms myself on my benchtop grinder. It went fine. The most annoying part was finding new split (roll) pins. FYI, 1/8" roll pins from Dorman will work. The pins are only 1" which is shorter than stock, but still long enough for this application. Anwyays, after grinding the arms down slightly, I can say that the ticking noised is reduced in intensity and the RPM range in which is occures has narrowed. So it made a different, but there is still audible and annoying ticking. I think I just didn't take off enough.
My next plan is to pull off the rockers again, paint them where contact may be happening, reinstall, then run them for a couple hundred miles. This should clearly identify which ones are still rubbing. That way I only machine the ones that need it. I think there only might be one that is still hitting.
|||