After about 1500 miles on the new rebuild and 10 track passes, there is a valvetrain noise ( I assume ) that is driving me crazy. Its a clacking noise that only occurs after the engine is hot, 175 degrees or more. Its extremely audible when you give it some gas and at idle you can hear a little. I've narrowed it down to the passenger side.

Car has Comp Pro Mag Rockers and did have GM PP lifters. I replaced the lifters this weekend! Car's normal ticking sounded a lot better but again, when hot sounded terrible.

I have no clue what the problem is and any information will be greatly appreciated!!!

 

I kind of had the same issue on my 96. when the engine oil got up to temp you start hearing a audible ticking. We(my brother and I) ended up switching out the promags for a set of comp high tech stainless rockers and everything is dead quiet now. Im assuming that the bearings were starting to make noise on the old promags, but have not pulled one apart to verify. We used the same preload on the new rockers vs. the old ones too. The main reason we switched the rockers was because a few have had issues with the promags causing engine failure. Did not want to risk toasting a forged stroker!!! The extra quiet valvetrain was an added bonus that we did not expect.

 

I guess I'll have to try swapping the rockers then. I'm just hoping there's nothing internally wrong.

Any other suggestions out there?

 

mine do EXACTLY the same thing. Dont worry about it, its just the rockers. I run a little thicker oil and the noise is gone now.

 

Mine is a ticking reguardless of the temp of the motor.

Some say Exhaust leak at the header, but im not sure.

Sounds like it coming from inside the valve cover but no clue. Havent had time to rip it apart.

 

I've changed lifters and went to thicker oil. This is a new noise louder than the previous ticking. And like stated before it only happens when the engine gets to operating temperature. So I have no clue. I have the covers off right now and I have narrowed it down to possible the no. 6 piston...

 

How much preload did you apply when you set those rockers?

 

No clue, engine builder put everything together. And a friend who is good with lt1s went over the valves after break in and before trip to the track.

 

Has he heard the noise you are talking about?

 

No this is new. Started after my last trip to track. I adjusted on the rockers with engine hot and running. I can make the noise louder but can't get it to quieten up. So maybe it is a rocker. It's not the ordinary lifter tick. It's a louder clack only when hot! So loud that ppl can hear me coming!!

 

Hey, check all your plugs, I had the same issue a while back... I thought I was chasing a valvetrain noise and took vids of it an posted it up an all and tried everything you have so far, new lifters and readjusting for hours, just to have my wife out there at one point say "hey should that plug wire shake that much", then I noticed that that plug was loose, tightened it up and the noice went away, and yes it only clanked when it warmed up and the metal expanded a little...

 

I just built a 355 and had a ticking noise I thought was the valvetrain but ended up being a header leak. They sound very very similar. I took a pc of hose and used it like a stethascope(sp) to locate exactly where the sound was coming from. Tightened the header bolt and the sound is gone with like 0 valvetrain noise. I also have the comp high tech stainless pro mag rockers.

 

How are you liking the stainless promags ac? Have you noticed them being less noisy than the old promags?

 

Hmm... I recently changed the plugs and the no. 6 is hardest to get to. Maybe it's loose a little. I will check this evening after work. Thanks guys. This may be the problem.

I had a header leak before and couldn't seem to fix it. So I used copper sealant and it worked great!

 

Dont have much run time yet, but they do seem alot smoother then the CM promags. They were pissing me off untill I found the header leak! lol!

 

The spark plug in question seems okay. I can't really get to it with ease, I have to remove the starter. And after work today, I just don't feel like it.

I noticed the rockers I think are making the noise aren't oiling very good. At revs, all or most of the rockers squirt oil very well, all over the headers to be exact. But there's a couple or just one that doesn't.

Could there have been an oiling problem the entire time that caused the rocker to eventually go bad? Just wondering. And if so, what could cause the no. 6 piston to not oil correctly? Engine is a fresh build, ground up.

Also, after start up, it takes a few minutes and a few revs before the engine really starts shooting the oil out.

 

Also, I was wondering about the stainless steel pro mags you guys are talking about? Are they the Ultra Pro Mags? I was looking but not sure if I found the right ones. If I need rockers in the near future I've already began shopping...

 

You might want to try adjusting the preload again, misadjusted valves can cause that. If that don't help try swapping rockers.
The comp high tech stainless rocker is the new version of the promag. The ultra promag is a composite version.If you call comp they don't recomend regular promags anymore, achotrod can give you details why.

 

lol!
These are the High tech Stainless Promags
http://www.compperformancegroupstore..._Code=HiTechSS

this is what happened to my old CM pro mag

 

Wow!

And what were the specs on your engine?

Mine is forged 383 with Trick Flow heads! I don't want this to happen to mine either.

Time for another upgrade!!!