BigDB

Z has a Lt1 in it. The engine hasst been started in 3 weeks and im buttoning up a cam install. Im setting the pre load for the valve train with the Pro Mag rockers from comp. They say to tighten until the push rod has resitance then add another 1/2 turn and tighten the lock. Now the lifters are bleed down and im thinking that when the lifter pumps back up with oil its gonna hold the valve open. Am I wrong? Should I go back and only tighten 1/4 turn?

lt1z28camaro

iTrader: (2)

I went with 1/2 turn, runs great for me..

SoxXpupPeT

iTrader: (34)

i did mine quarter of a turn. mine are NA and make a very very tiny bit of chatter. a half a turn should be good

Fire67

iTrader: (3)

Alot of people have issues with valve adjustment because they do not pump up the lifters before adjusting the rockers. I always have the plugs out, and take the rockers off of the stud. Then turn the motor over until I see oil coming out of the pushrod tip. Then I install and adjust the rockers one at a time in sequence. Never failed me yet. I also use 1/2 turn past a little resistance.

James Montigny

iTrader: (13)

See attached documents.

SoxXpupPeT

iTrader: (34)

i should of mentioned that i turn my engine over afew times to make sure the lifters have oil in them so that when you set valve lash there all where there supposed to be

camar0corey

iTrader: (22)

I actually went a full turn this time with the promags. I'll let you know Monday when I try to fire it if they ended up being too tight. I think I mashed two due to spinning the thing higher than I should have been.

buffman

iTrader: (9)

I'd just go by there recommendations so the car can be started. Once the car is startable do a dynamic lashing. set all to 1/4 or 1/2 Turn. Call it a day. Make sure those allen set screws are tight. Dynamic is a lot more accurate. Loosen poly till clacking. Tighten (i use fingers for precise control) until quiet. Set preload. Hold poly then get that set screw tight. Done. Move on to next rocker.

James Montigny

iTrader: (13)

If it makes bad noises or looses power up top, you're probably too tight and losing cyl pressure at high RPM.
So many people drive around like that and never known it.

SoxXpupPeT

iTrader: (34)

you could run the car and adjust them. try a 1/4 turn and see how it feels. mine feels real smooth. the higher the RPM the smoother it gets its beautiful

leadfoot4

iTrader: (1)

I agree!!



FWIW, ARP says to tighten the set screws on their poly locks to 22 ft/lbs.

1redta

sorry to high jack but when using the ARP's to replace the comp polylocks what size shoulder do I need for the 7/16th CC rocker? TIA Art

AChotrod

iTrader: (17)

LE told me, Make sure the rockers are adjusted to 1/8 past zero lash on my set up.

SoxXpupPeT

iTrader: (34)

only 1/8th ? thats probably because your running a hefty cam, so you dont lose power up top

StealthFormula

iTrader: (35)

^^Thats what I was told and did as well. They make noise but the car runs awesome.

leadfoot4

iTrader: (1)

Not sure what you're trying to find out...All polylocks are pretty much the same diameter down the shank, and they seat on the trunion of the rocker arm. The only difference, especially when talking about the ARPs, is the size of the hex where you place the wrench. The APRs have a 9/16" hex, and most of the others are 5/8".

1redta

the poly lock come in sizes .550 .600 .650 and .750 The comp pro mag 7/16 stud NSA uses the .550 shoulder

leadfoot4

iTrader: (1)

I guess you learn something every day... Would the larger diameter locks be used on small block Chevy rockers, however?

1redta

i fyou go to comp cams website you can find it here
http://www.compcams.com/technical/Ca...106-07/276.pdf