LT1-LT4 Modifications 1993-97 Gen II Small Block V8

LOUD Comp rockers (Update!!)

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Old 01-07-2014, 06:58 PM
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Default LOUD Comp rockers (Update!!)

I had my head gaskets replaced a while back and thought the rockers were louder than before when I dropped the car off. I took it back and had them readjust, still sounded the same. So I just finished adjusting them myself one cylinder at a time, half turn passed zero lash using the pushrod up and down method, still loud. It sounds like a very bad exhaust leak. TICK, TICK, TICK. Rockers are Comp Ultra Pro Mag 1.6, new LS7 lifters. I want to use the engine running method but I have the 24x swap, I would need to figure out a way to hang the coil and bracket above the motor.

Last edited by ascastil; 01-18-2014 at 12:13 PM.
Old 01-07-2014, 09:58 PM
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have the valve covers been trimed or modified to clear the RR?

and confirm you don't have a exhaust manifold/header leak making the "tick, tick" sound.
Old 01-07-2014, 10:33 PM
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Originally Posted by ******
have the valve covers been trimed or modified to clear the RR?

and confirm you don't have a exhaust manifold/header leak making the "tick, tick" sound.
Canton tall valve covers, header gaskets are good. Both sides sound equally loud. They have been adjusted before by a different shop and they were quiet, thats what I was used too. Now Im wondering if they were to tight and the most recent shop that adjusted them and now me did them right. They are loud enough I can hear them if there is a car next to me or Im driving along a wall, with the hood down even.
Old 01-07-2014, 10:58 PM
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I was doing some reading about people having loud lifters after several attempts at adjusting them. One guy switched oil weight. I was using Valvoline 10 30 but I have no idea what this performance shop used that I took it to. Im gonna throw some 10 30 or 40 in there and see what happens.
Old 01-07-2014, 11:38 PM
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how much preload are you running? how many turns past zero lash?
Old 01-08-2014, 10:10 AM
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Did u clearance the rockers to the spring retainer on top through the vlv cycle? Clearance the rocker to the spring through the vlv cycle? Did u clearance the rocker arm on the stud through the entire vlv cycle - the slot needs to clear the full arc?

Try a unbent paper clip,
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Old 01-08-2014, 11:30 AM
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Im not sure what you are talking about cardo. Ill have to look into that. Another thing worth mentioning is that the rockers are very quiet on startup. They get loud after the car warms up. Thats what made me think about oil.
Old 01-08-2014, 12:04 PM
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This loud?


Do they sound like that, or even louder? Mine were quiet, then I had a valve spring break up near the top. I replaced all the beehive springs (not sure if they were Comp springs or PAC springs) with new PACs, afterwards I brought each cylinder to TDC to do the rockers, tightened the polylock until I couldn't spin the pushrod anymore, followed by 1/2 turn.

I am also using the ultra pro comp 1.6 rockers, NSA, LS7 lifters with around 30k on them, hardened pushrods/guideplates.

Oil wise I have used only conventional 10w-40 in this motor since it was rebuilt two years ago, my builder told me to use that weight due to the crank bearings he installed.

That video is how loud they are at the moment. I'm not sure if I'm going to go back in there again or not. Previously they were not that loud.

(Not thread related or I guess in a way it is, but why does it sometimes insert the youtube video directly and other times make a clickable link? Am I losing my mind?)

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Old 01-08-2014, 12:30 PM
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Originally Posted by camar0corey
That ain't right. Too loud and can hear at least one distinct rocker. Should be more of a mechanical whir than a tick.
Old 01-08-2014, 04:13 PM
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[QUOTE=camar0corey;17935435 afterwards I brought each cylinder to TDC to do the rockers, tightened the polylock until I couldn't spin the pushrod anymore, followed by 1/2 turn.

[/QUOTE]

....you don't tighten poly until you can't spin pushrod any more than go another 1/2 turn

you tighten poly (with fingers) until there is no up/down movement in PR then go 1/2 turn more.

if you did what you said...your lash is to tight.....and if it was done that way before when you broke a spring that is most likely why. bent push rods and wiped cam lopes can also result from a lash that is to tight

RR are louder than stamped rockers and have what is often refered to as a "sewing machine" sound to them
Old 01-08-2014, 08:27 PM
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Well I just started it again to make sure I wasnt crazy and they are as quiet as can be when the car is cold. I know if I drive it around and bring it up to temp theyll start ticking. What do you guys think? Should I try adjusting them again? Its a PITA now that I have all those coils on there now, otherwise I would have already. Not real sure itll be any different though. Pushrod up and down till no movement, 1/2 turn more, tighten allen lock. I did it one cylinder at a time using Shoeboxes site.
Old 01-08-2014, 08:40 PM
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Since the engine has been ran you can set them cold with no problem.

This is how I've done it for years.

Make sure you are on the base circle of the cam. Roll the engine over by hand or use a remote starter(much easier). Let's say you start on cylinder #1. With one valve at max lift adjust the other. Spin it loosely between your fingers as you tighten the nut. When it doesn't spin freely that's zero lash.

FWIW I've found 3/4 turn is about perfect on SBC's w/ iron block and aluminum heads w/ stock style lifters.
Old 01-08-2014, 08:52 PM
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Originally Posted by LilJayV10
Since the engine has been ran you can set them cold with no problem.

This is how I've done it for years.

Make sure you are on the base circle of the cam. Roll the engine over by hand or use a remote starter(much easier). Let's say you start on cylinder #1. With one valve at max lift adjust the other. Spin it loosely between your fingers as you tighten the nut. When it doesn't spin freely that's zero lash.

FWIW I've found 3/4 turn is about perfect on SBC's w/ iron block and aluminum heads w/ stock style lifters.
More than likely Ill try it again. Im really curious as to why they are quiet when cold, and loud when warmed up? They sound like a high end sowing machine right now, I love it.
Old 01-08-2014, 09:20 PM
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Because when the engine warms up aluminum expands more than iron. Tolerances are different at different temps and between different metals. That's why you have to run a little more preload. On an all aluminum motor like an LS1 you have to run even more to compensate for the engine "growing"

Also when it's warm the oil thins out some.
Old 01-08-2014, 09:39 PM
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Do you think Im on the right track if I go back in there and do 3/4 turn and not 1/2 since I know its quiet when cold? Maybe another 1/4 turn will quiet them up when warm?
Old 01-08-2014, 10:02 PM
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Yeah I think 3/4 would be fine.
Old 01-08-2014, 10:04 PM
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Try 3/4 on one side and side of that helps. If it does do the other side.

If its as loud as that video you have oil pressure/flow problems.
Old 01-08-2014, 10:16 PM
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No, it doesnt sound at all like the video. Thanks.
Old 01-08-2014, 11:07 PM
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If I remember correctly I think those rocker arms are noisy. For some reason I remember that when I used them on a build for my friends 93Z. I also remember I had to cut some bracing off the inside of the valve covers because they are wider than stock. Just thought I would throw that out there.
Old 01-08-2014, 11:22 PM
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Originally Posted by ascastil
Im not sure what you are talking about cardo. Ill have to look into that. Another thing worth mentioning is that the rockers are very quiet on startup. They get loud after the car warms up. Thats what made me think about oil.

Take a read of this from Crane: http://www.cranecams.com.au/index.ph...ent/article/59

cardo


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