MICAH HERRON

iTrader: (3)

I have been chasing issues after the heads and cam job...what I believed was an exhaust leak...well I am not sure anymore.

I replaced the header gaskets, the air system gaskets, the header-collection pipe seals and swapped the plugs, torq'd eveything down to the service manuals recommended specifications and not I am going because I didn't even make it down the road and the sound was back, there is also a new sound and to be perfectly honest, I am out of ideas.

I have dumped so much money into the heads/cam, torq converter and all the tuning and I am tapped for months. I am to nervous to drive the car and well...I guess I will just let it sit. I really don't see myself going to the CRUISIN now, things are just not working in my favor.

This sucks so badly.

Micah

King James

iTrader: (13)

You need to be a bit more specific on the problem and mods installed.

Doc

iTrader: (9)

Yes, what H/C combo? When do you hear the noise? All the time? Idle, cruise, Sustained rpms? Where does the sound seem to emmanate from? Is it from a particular side? Drv or Pssg? Have you pulled the valve covers? What was your pre load like? Are you using stock lifters, rockers, pushrods? Many possibilities. I don't want to go on and on and sound like a dick but, if you seriously want some help we need details. I feel your pain brother. There is a reason for this...don't let it get you down- just deal with it and learn from it and then pass on this experiance to others on this board and good karma will come your way.

MICAH HERRON

iTrader: (3)

Well, I installed a cam and a set of CNC'd LS6 heads with 918s and hardened pushords and LS6 OEM lifters. I have shorty heads and replaced every single gasket that had to do with the exhaust or air system as well as the plugs. Had the NGK TR6s and returned to the ACDelco Iridiums and ensured all things were torq'd per service manual. When I got the car back together and started it, I heard the valve train much more clearly, but I also heard a grumbling/grinding type sound (wife said she couldn't hear anything) coming from the driver side of the car.

Before I went hunting I had a clicking/slapping sound coming from the driver side of the motor, sounded a lot like an exhaust leak so that is why I replaced all gaskets. The sound wasn't really noticeable during city driving, more during the highway driving. The sound would just be extremely loud and steady, however when you exited and the car's speed slowed, the sound would disapate and often just disappears. I had a buddy of mine with me and he was certain it was an exhaust leak and wanted to hear it idling at his house which was 2 miles from the interestate and by the time I got there the noise was gone. :*****:

After my drive tonight when I got home the car seemed to be fine. I just don't understand. I am certained that if I get on the interstate it would be back. :crazy:

Thanks.

MICAH HERRON

iTrader: (3)

a COMP 232/236 .575/.578 with a brand new set of CNC'd LS6 heads that have LS6 retianers (new) and 918 springs. I have CHROMOLOY Hardened pushrods. I hear the noise at cruising speeds and it is a come and go sort of thing. It seems to be from the driver side right behind the instrument panel. I pulled the valve covers the first time it happened and checked the integrity of the rocker arms and springs, everything looked fine, thinking of doing it again to check pushrods. It is a noise that is not always there, seems to return when I put a load on it while cruising on the interestate and often disappears after I have exited and went through a couple of stop lights. I am willing to drive to Orange Park and have you drive it.

I am not offended by your post and understand completely. In fact, this started when I was visiting family in Jacksonville.

goober35

iTrader: (1)

Are u sure you are not just hearing vavle noise. When i drive my car i her what is best described as a sowing machine sound under the hood. It is right behind the gagues as you say. There is no leak in my exhaust what so ever. I know the rockers are not tapping because they are tq to my spec not GM's pos spec.

If it is just a tapping sound under the hood you are going to have to get use to it.

MICAH HERRON

iTrader: (3)

No, I wish it was, but this is my second LS1 (1999 Z28 previously) running a cam and it is not the sewing machine sound that we are used to having once the cam is done. This really sounds to me like an exhaust leak.

heavymetals

iTrader: (3)

You could have a crack in the header that is opening up (rare).

What exhaust manifold gaskets are you using?

MICAH HERRON

iTrader: (3)

I am using a set of alimunuin gaskets that I bought from SUMMIT racing for the LS1 application.

heavymetals

iTrader: (3)

What headers are you running?

Those noises that come and go and never appear when your looking for them are all part of being in MOD HELL.

jermzz

iTrader: (18)

Yeah what headers? do they have smog provisions? one of my egr tubes got a crack in it and it was making an exhaust leak. Also, did you check the intake gaskets before you put the intake back on? Might be a small intake leak aswell.

goober35

iTrader: (1)

Pull them headers and inspect them bad boys. I know it is a pain in the *** but sounds like you like things perfect so you should not mind to much.

Doc

iTrader: (9)

Thank you for the very detailed response. You are not alone. I am having the exact same problem. You donot have an exhaust leak trust me. I have EFI Live and I scanned the car last night. I bet yours is doing the exact same thing. I pulled the valve covers last night. What size pushrods do you have? I have 7.4 Chromoly hardened. I have cnc'd ls6 243 factory castings with 2.05 valves, double springs, and a 228/228 .588/.588 114 comp xer cam. I talked with the folks who sold me the stuff and they asked me to take #1 to td center and measure how many turns I needed to get to the preload 22ft. lbs. I work in a calibration lab by day so, I know that the tq wrench is traceable to NIST. It took me 3 1/2 turns to get to 22ft. lbs. The people who sold me the set up thought that was way too much and were collectively thingking this thing out but "probably were going to send me some shorter pushrods." Like 7.35's . Keep in touch. Come on down to OP if you need to. I am here to help.

AdamSS

iTrader: (3)

yup, doc is right.... valvetrain geometry (i.e. preload) is a VERY important thing to check, and very often ignored by DIY-folks.
Check the geometry first, before you "tear it" apart...

MICAH HERRON

iTrader: (3)

Thanks guys, I did torq it to the spec of the service manual, so I was thinking that was good. I am running the stock length hardened pushrods. I am dropping the car off with the local VETTE Shop Owner and he is going to personally drive it. The car only seems to make the noise when I have been cruising on the highway for extended periods of time (at least 10 minutes). After return home and putting it in park at an idle, there is no noise. If I knew how to host and post video clips, so you all can hear it. When the car was started this morning from a cold start it is a normal cold valve train sound, driving around the city (stop and go) things are normal, it is when a load is held for an extended period of time. Trust me it is loud.

I am sure that Kerry will go step by step to get the car right after I apparently screwed it up.

777

iTrader: (21)

In your case it sounds like you need longer pushrods, not shorter. Like 7.425 or 7.450. I bet this is the current problem with this guy's car as well. I ordered 7.425" pushrods for my car because of the same stuff ya'll are talking about.

MICAH HERRON

iTrader: (3)

I hope and pray it is something like a pushord length too. I am having a pro look at it and he will check everything out! I hope that he finds the issue quickly and it is something small.

777

iTrader: (21)

Yeah, you can get a pushrod length checker from www.ls1speed.com.

MICAH HERRON

iTrader: (3)

The car is at the VETTE Shop.

SS-35th

iTrader: (2)

My 35th has a similar problem after I installed a set of MAC Headers, I hear a ticking that I thought was a check valve from the AIR system. Well I removed the AIR system and I still have the ticking noise. The noise is bad when it's cold and when the engine is under load, but when the engine is warm and not under load the ticking goes away. I think I have found the source of the noise, it looks like I have a small leak where the header meets the head at the primary tube closest to the firewall. I used brand new GM gaskets when I installed the MACs and I torqued all the bolts properly so I don't understand why it would be leaking but there is a small build up of carbon back there. I'm going to replace the gasket and see if it makes any difference, hopefully it will fix the problem and I won't have to replace the header, just letting you know my situation, it may be something simple with your car as well.