Big Z

iTrader: (6)

My 383 ls1 has comp roller rockers on it, and the comp instructions say to tighten them 1/2 turn past zero lash. Does anyone have any experience with these things? They just seem noisy and I was wondering if that wasnt enough preload. I checked the pushrod length when I put the motor together and the wipe pattern looked good. Thanks for your help

Big Z

iTrader: (6)

forgot to mention, I'm using the ls7 stock replacement lifters

D Hammer

there is no lash adjusment with ls rockers you set preload with pushrod length

hartman

iTrader: (4)

Unless you have adjustable rockers.

Big Z

iTrader: (6)

yeah they are adjustable. There isnt a pedestal with a bolt like the stock rockers, theres a stud the rockers ride on. Oh and a word of advice to those that buy comp roller rockers, they didnt fit under my valve covers, I had to buy spacers.

LilJayV10

iTrader: (39)

If they are stud mounted/adjustable they are like the old SBC engines. As one valve starts to open adjust the other one. Spin the pushrod between your fingers and slowly tighten the nut. When the pushrod stops spinning freely that's zero lash. Anything after that is preload. I use 3/4-1 turn for years and that seems to be a good spot. Make sure you tighten down the jamb nut so it won't back off. Turn the engine over till that valve starts to open and adjust the other. Repeat this for the rest of the engine.

LilJayV10

iTrader: (39)

seems .060-.100 is acceptable and .080 is preferred

Havoc40

Google EO/IC valve adjustment method. Preload is determined by the threads per inch (pitch) of the adjustment bolt or poly lock. Figure out what that is, divide 1 by the pitch, and that gives you what 1 turn (1 thread) equals. I also use .080-.100 on standard hyd. lifters.

FWIW, typical sizes are 3/8-24 UNF and 7/16-20 UNF. That translates to .050"/turn for 20TPI and .042"/turn for 24TPI.

Randy WS6

iTrader: (69)

This is the way i adjust my comp rocker arms on my LS1, Read the hydraulic lifter adjustment procedure.
Do one cylinder at a time.

http://www.cpgnation.com/forum/comp-...ment-2076.html

Havoc40

That's what is commonly referred to as the EO/IC method (exhaust open/intake closed). Great article btw. I know car craft put out something similar but I couldn't find it earlier.

Big Z

iTrader: (6)

Good info. I'll have to try and check the thread pitch on those things saturday. so if I'm looking for around .060 to .080 I'd need at least a good turn, turn and a half depending on the thread pitch. I actually used those instructions randy ws6 posted and comp only recommends half a turn. Seems like that would only be .020 to .025 or so, maybe thats why my valvetrain is noisy. Thanks for the help guys, I'll update with my findings

Randy WS6

iTrader: (69)

Ive been using this method 1/2" turn and my engine is quite, but it might be because i use Mobil-1 15W/50 performance oil. Isn't the .080" depth for a stock style engines ? I just figured that were i'm running Comp rockers and performance lifters that they would know what the reload would need to be. And a stock engine usually don't rev past 5500rpm's , were I rev at 7400rpm's. So Comp my be setting the lifter reload for high performance engines that rev high for extra clearance and spring pressures & rpm's.

Havoc40

I don't have the time to go into the differences between a shorter vs. longer preload at the moment. But from extensive testing, there is absolutely no reason to have .100+ travel in high RPM applications. Even at .080" preload, LS7's will still have .100"-.120" travel. Your setup and shift point would love some short travels

Randy WS6

iTrader: (69)

So are you saying, that i need more preload or more adjustment. How much preload do i need ?

Havoc40

Depends on your lifters. But that post was referring to standard lifters and your comment about high RPM and .020"-.025" preload. Standard meaning LS7 or even aftermarkets keeping roughly .200 available travel. I like keeping .125 travel on standard lifters, always has shown stability in my tests vs. running shallower or deeper. Subsequently that is where a lifter will quiet up sometimes when set shallow. Might be 1 or all 16. Which happens when the leakdown rate on a certain lifter in the set is on the low side, on top of a shallow preload. Thus you always hear the fix, more preload.