OK guys, I've got about 3000 miles on the rebuilt L98/ZZ4 cam project. After a few weeks, some ever so slight chatter started comin' out of what sounded like the valve covers. Now about 9 months afterwards, it really is ticking away.

I've had a few mechanic friends listen, and countless other shadetree wrenchers, and the unanimous verdict seems to be that the rockers have just settled and loostened up a bit. That brings me to a few questions.

First, right off the bat, is this dangerous for my motor? She still runs like a champ, but it's to the point where it needs to be fixed. I'm gonna do it in the next few weeks, but am I hurting it to put a few miles on it here and there? It doesn't seem to have caused any damage so far.

Second, what causes this? IIRC, when I set the lash, I gave it a half turn past the tension point on the pushrods. Maybe I didn't tighten it enough? The rockers and nuts are the original 170,000 mile pieces, maybe I need new ones?

Third, do I need threadlock? I didn't use any the first time. Someone mentioned that the nuts are self locking. Maybe they're worn out?

....any comments or suggestions?

Thanks!

 

Did you put any new parts at all in the valvetrain? If anything's new (cam included) it'll loosen the clerances a little as it "wears in" and this can cause the rockers to tick after a couple thousand miles. The nuts are self-locking, and if they haven't been off more than 3 or 4 times they're not a worry. It's pretty common to have to re-lash the valves after the engine breaks in good. Don't sweat over it, just do it when you get the chance.

 

Thanks for the reply!

...I was having nightmares of a rocker flyin' off at high RPM!!!

....I should be able to get to it soon, but I'm gonna try to replace the stamped rockers with some steel ones, and as always, there's a few things needed first

 

No worries there if anything it will help you out. Mine are all loose like that but I did that on purpose only turned them all about a 1/4 turn will make it sound like u have a solid roller but it put out a few extra HP. If you drive your car alot and put on alot of miles I wouldn't suggest doing that but I only put on 3k a year at the most.

 

Are you running the stock heads? If so, one of the pressed in studs might be gradually making it's way out.

It's more than likely an adjustment that came loose (common), a sticky or collapsed lifter, bent pushrod... or a stud making it's way out.

 

Yea, I had thought of that too. I'm gonna check for it when I reset the lash.