LFZ

whats do i adjust them too?? zero tolerance? does it matter since they are vortec heads? and why do i need to adjust the rockers? this is a crate motor?? because i can't get them to stop chattering, and my mechanic says they need some adjustments done. thanks. :banghead:

cardo0

You really need to do a little research for this REDSHARKY. :yesnod: Since I recall your mill is a ZZ4 and those use roller cams/lifters - the adjustment maybe different than flat lifters. Any late model shop manual for corvette - say 1988-1995 should describe this. :chevy
Now for flat tappet lifters I like to adjust them at idle by loosening the rocker nut until you can feel/hear pushrod lash. Next step is to tighten rocker nut until pushrod at zero lash but I can still easily turn rod with my little fingers (yes while engine is running at idle) and tighten 1/4 to 3/4 more (yep I use 1/2 turn). Since your valve covers are centerbolt types I doubt you have taken an old cover and cut off the top to expose rockers and allow acces. Without this or some other type of barrier, oil will splash all over the hot exhaust manifolds, engine compartment, and you.
Plan "B" - without splashing oil - can be done while engine stopped/cold. For this you need to turn the engine (remove spark plugs) by hand slowly and observe the rockerarms/valves are shut while cam lobes for selected cylinder are on the base circle. The lifter adjustment would be exactly as before (with engine running) - 1/4 to 3/4 turn past zero lash. Now you really need a reference book for this to verify proper adjustment for roller lifters. But this is a good skill to learn for future motor work. :thumbs:

BSeery

did you change heads, rockers, springs or something on the motor ?

Mine have been running for a year and 1/2 and have not needed any adjustment.

Best way that I do adjustments it to buy the little spring clips that block the oil hole on the rocker arm (only works on stamped stock style rockers) and use them. I adjust the rocker while the motor is running. I back the nut off until I hear it start to rattle. Then I tighten until the rattle stops, and then go 1/2 turn more.

Good luck.

Vetterodder

If you are talking about a GM crate ZZ4, you do not have Vortec heads but valve adjustment will still be the same in either case. Adjust them like Cardo0 said. To minimize oil splash, they sell clips for stamped steel rockers that divert the oil from the pushrods and they help a lot. Reduce your idle to rpm as low as possible while adjusting them. Besides reducing oil pressure so that less oil is being squirted, it also reduces the frequency of movement and you can better hear the individual valves.

Cookwithvette

As others have said, unless you've changed them your ZZ4 doesn't have vortecs. It uses L98 heads. The Chevy manual that comes with the engine calls for 1/4 turn past 0 lash. If you want to do it with the engine off you can use the twirl method. The absolute best advice I can give for the engine off method is to read and fully understand the following article...
https://www.corvetteforum.com/techti...=116&TopicID=3

Took me a couple reads before I had FULLY absorbed the info but well worth it. It's written by Lars so the info is good. I'd also recommend printing the procedure section and taking it with you as a reference sheet while you're out working on the car.

Good luck! :cheers:


[Modified by Cookwithvette, 11:42 PM 6/6/2003]

CDaniel525

So what do you guys do to keep oil from splashing everywhere when you have roller rockers?? I got the hotcam kit for my zz4 and those rockers came with it......I never wanna adjust them again after the mess it made first time :sad:

BSeery

order a spare set of rocker covers, or at least just one.
Cut open areas just above the locknuts and big enough to get a socket on.
Bolt the modified valve cover on and fire it up.