jub jub

Has anyone...anyone at all ever got rid of the clacking after a cam install?

After having a Comp XER cam installed in my Z06, it's clacking to "beat the band"! It's very annoying and I know it's not normal because a friend's exact same set-up doesn't clack like mine. Only does it after the engine gets warm!

I've had the O-ring TSB performed but that didn't do anything. I'm so pissed off I could just throw this engine in the dump and start over.

BTW, before anyone says it has to do with the install, I will say that it clacked before the cam install, but not near as loud. The cam install was professionally performed by NLP so I know that's not a problem. I think it has to with a faulty lifter or insufficient oil pressure to one or more lifters. Who knows, it's one of the great mysteries of life.

Sorry for the rant but I just had to get this off my chest!

madpwr1

iTrader: (3)

hey instead of that just slide that motor over to me, got $20 bucks with your name on it.

SS346Ls1

Get a louder exhaust. Problem solved.

jub jub

It's already freaking loud!

~JOSHUA

iTrader: (92)

Does it sound kind of like a diesel clack or clattering? Definate sign that the sound is piston slap. It has to do with the barrel shape they cast the pistons with. It is supposed to expand but engines on the high side of tolerances slap loudly. My '02 'Hawk clatters lightly before and after my valvetrain work. Time to invest in a Blueprinted shortblock!!!

jub jub

What's really weird is the fact that it got louder after the new, high lift cam. It almost reinforces a lifter problem, or at least valve train related. What is really weird, if you do a search on the subject, you really don't see very many posts that claim a successful repair.

I was talking to my wife about this and she gave me the go-ahead for a new forged short block so now I'll start researching what are the best parts to use.

The saga continues!

Nightclaw

Well, for those of us who DON'T have a green light for a forged short block, anyone know what the heck causes this? I never had this ticking/rattling before I did my cam install (TR 224/224/.561/114), but it's been driving me nuts for the year I've had it installed. I'm almost to the point of putting the stock cam back in, power gains be damned. I have a high-volume (Thunder Racing) oil pump and I put a new O-ring in when I reassembled it. Oil pressure is 60 when cold and 40 when hot, so I don't think I pinched or tore the O-ring on reassembly... Help!

-Brian

strokedls1

iTrader: (1)

Just because you went to xyz shop does not mean that they did it correctly. Most people do not take the time to individually adjust the valve train with shims. If the preload is off alot it can make a motor super noisy. Might try adjusting the preload again before just giving up and building a new motor.

Nightclaw

Forgive me if this is a "fawking moron" question, but where exactly would I shim the valvetrain, and where to get said shims? I can't recall ever having seen valvetrain shims advertised anywhere...

jub jub

OK, I can buy that. I took the liberty of checking the preload and push rods (for bending) on each cylinder. With the lifters on base circle, there was 1-1/2 turns from where the push rod makes good contact with the rocker arm. I believe that is sufficient on an LS6 with stock lifters.

This is so darn frustrating. I don't mind a little valve train noise but when your engine clacks like an old truck, it makes you want to just throw in the towel and forget about performance. Dohhhh...did I say that?

strokedls1

iTrader: (1)

If that is 1.5 turns that is about right for the stock lifters. If it is .5 to 1 turn you might want a little more preload. I would hate to think that a 2002 ZO6 motor has that much piston slap, but who knows with GM quality control. What springs and pushrods are you using?

Nightclaw- Crane and comp cams both make little square shims that are 15 and 30 thousandths. Looks like a thin washer thats square. I got some from PAW. You place these under the rocker rail on the rocker stud bolts to adjust preload for each rocker. It is a pain in the *** to do but pays off with a quiet valve train.

jub jub

Yes...it's one and a half turns plus a tad more to get to 22 foot lbs. Springs are duals that come stock on the AFR heads and I'm not really sure what brand they are. Push rods are Comp.

I guess I'll yank the heads this weekend for some off chance there is bad lifter.

pphilli1

iTrader: (1)

I INSTALLED A COMP G-1G CAM-588/575 LIFT & EXPERIENCED MASSIVE
CHATTER WITH THE STOCK ROCKERS,I REPLACED THE LIFTER WITH NEW
COMP OEM STYLE,COMP 5/16 PUSHRODS & COMP 1.75 ROLLER ROCKERS
JOE OVERTON IS DOING THE VALVE TRAIN & TUNE.EVERY ONE I TALKED TO
SAYS THAT AN LS-1 WITH A CAM WILL SOUND LIKE A SEWING MACHINE-MINE SEEMED EXCESSIVE,HOWEVER I HAVE NOT GOT IT BACK FROM JOE
SO I DON'T KNOW HOW MUCH QUITER IT WILL BE.I'LL POST AGAIN ON
SUNDAY OR MONDAY AFTER I PICK IT UP. undefined

Nightclaw

Cool, thanks for the info. I don't mind doing a tedious job if it will pay off. Next to the clutch chatter from my Spec 3, the post-cam-install valvetrain clatter is my biggest gripe right now, so the time to do it is worth it to me. Thanks!

-Brian

Brent02

Also, use some assembly lube or greases to keep the shims in place. You only need a small amount.

PunisherSS

7
7ub]Has anyone...anyone at all ever got rid of the clacking after a cam install?

After having a Comp XER cam installed in my Z06, it's clacking to "beat the band"! It's very annoying and I know it's not normal because a friend's exact same set-up doesn't clack like mine. Only does it after the engine gets warm!

I've had the O-ring TSB performed but that didn't do anything. I'm so pissed off I could just throw this engine in the dump and start over.

BTW, before anyone says it has to do with the install, I will say that it clacked before the cam install, but not near as loud. The cam install was professionally performed by NLP so I know that's not a problem. I think it has to with a faulty lifter or insufficient oil pressure to one or more lifters. Who knows, it's one of the great mysteries of life.

Sorry for the rant but I just had to get this off my chest![/QUOTE]

I had a similar problem when I installed my cam on my LS1. It turned out to be, in my case, the motor oil. The local shop that was doing the oil changes on my car, was using the the wrong oil viscosity. My oil viscosity was too light (10W30 Amsoil Syntetic) and even though my oil gauge was always showing normal oil pressure, I was 1 quart low on oil. Too low on oil, and too light oil viscosity, was allowing for too much friction creating the noise.

MSF

Project GatTagO

iTrader: (7)

The main cause for this problem is that most high lift cams have a reduced base circle. So when when the engine warms up and the aluminum block and heads expands the factory preload is not enough to compensate. With a reduced base circle cam, a slightly longer pushrod is required in order to use the stock, non adjustable valve train. I am in the process of curing this exact problem on my LS6 with a Comp Cam.

Andrew

jub jub

Could you please keep us updated on this. Mine is quiet when I first start it so maybe longer rods would help.

66deuce

iTrader: (1)

that would be my guess as to your noisy valve train.i've read in that new book on ls1-ls6 motors that one company in particular likes to run a little less pre-load than stock,it supposedly is worth a little more power and a little quieter valvetrain.

Project GatTagO

iTrader: (7)

I will keep you guys posted. The first thing I want to try is going over the torquing proceedure one more time to eliminate the possibility that I have a few loose rockers. Then I plan to see how the wear pattern looks on the tip of the valve. If the pushrod is indeed too short, it will show up on the valve tip. If the wear on the tip of the valve is indeed off, then a set of slightly longer pushrods should cure the problem.

Just to make it all clear, piston slap is very loud at start up and gets quiet after 60-90 seconds. The noise we are hearing is the exact oppisite. Nice and quiet at start up and it gets louder as the engine warms up and things expand.

Andrew