Intercooler2

iTrader: (24)

I had a post about what a failed/failing lifter has for symptoms but got little info. This stemmed from a noise I have picked up on going WOT of a knock/rattle you can mainly hear on the driver's side. One suggestion was to check the car underneath for the exhaust hitting, etc... It hadn't been changed at all from when I did heads/cam/intake but we put it on the lift regardless. Nothing found. Everything looked good and no shiny places like a new hit or anything.

What we did find:

- Driver's side head had ever so slight drip of coolant near the bottom/rear head bolt. I mean very slight. I know this isn't to out of the norm for Cometics sometimes. Should I be worried?
- Nothing abnormal looking in the flywheel area
- No oil in the water. No water in the oil

The motor idles, acts and pulls just like normal really. Damn smoothe!

So my buddy suggested maybe the cold temps we are seeing did something to the tune and may need more octane. So I put a couple gallons of race gas in. No change!


I had read a few stories about the LS7 lifters like I went back with in mine. Crusing along no noise. No noise at idle. Nothing on a blip of the throttle. It's mainly when you go 4k plus RPM and load it up. Could it be a weak lifter/lifters bleeding down like I read about? I never saw any symptoms but I'm pretty positive my issue is internal now which sucks!


Should have just stayed SI!

JPH

iTrader: (2)

Check #7 exhaust rocker(driver rear), and see if the trunion is starting to break/let go?

Intercooler2

iTrader: (24)

Okay. Why 7? What am I looking for and what would the noise/symptoms be for that? What can happen?

Intercooler2

iTrader: (24)

I'm really starting to wonder now if I lost a valvespring. Maybe one busted and it is the piston hitting the valve. Crap!

Also anyone experiencing a slight drip from the Cometics? Is a retorque ever needed or some sealtabs?

Intercooler2

iTrader: (24)

Any ideas given the sound and how it runs?

vettenuts

iTrader: (4)

What did you use for head bolts? Did you check for surface roughness and flatness before installing Cometics? Have you had the oil analyzed?

Based on your own assessment, pull the valve covers and inspect everything. If nothing else, it will ease you mind if nothing is found.

Intercooler2

iTrader: (24)

No didn't check the block for roughness or flatness (in the car and was fine as it was). Cleaned it and used ARP bolts. I know the Cometics can/have leaked in the past so a couple of drops isn't alarming.


I know since their is an upgrade to the stock rockers I figured someone would have a couple of pics or some details on what symptoms it gave.

My worst fear is the second one. Valvespring broke and its hitting the piston top. Wanted to hear stories from others that had that happen.

87silverbullet

iTrader: (11)

If a valve was hitting a piston you would be losing compression on that cylinder and the motor would be misfiring from having damage to that valve. It might be something in your valvetrain letting go.

Pull the valve covers and check the rockers since that is the easiest think to check. If they are ok pull the rockers off and get someone to turn the motor over by hand and put your finger on the pushrod to see if you can feel any abnormality (lifter dragging). Make sure the pushrods are not bent.

My buddies WS6 had a slight valvetrain noise that got progressively worse over time, but were talkin months here. He was going to work and the noise became awful. We brought it back to his house and yanked the heads and it ended up being that the roller broke off the lifter and just the lifter was riding on the cam with no roller. It ended up ruining everything with the chewed up metal being everywhere. I think the roller stopped turning and was just sliding on the cam like a flat-tappet lifter then after time it finally broke off.

Intercooler2

iTrader: (24)

I have been doing tons of searches here for stock rocker failures. Can't find any pictures or what exactly the symptoms were.


I also searched for broken valvesprings. No videos found but did see a couple of pics. If it had one broken... I'm confused whether it would run right or not. Seems the ones I saw said it won't.

In my case it runs like a normal trouble-free motor until you hit it and get over 4k RPM.

I have driven it this way from the looks of it for at least 100 miles. I just wonder if it has another 10 in it to make it over to the shop one last time to pull the cover.

I hope it isn't one where I have to pull the top half off again like a lifter or busted spring that bent a valve.

Intercooler2

iTrader: (24)

Who has used some seal tabs or other sealer after Cometic install for a couple of drips?


On my Buick I used the GM tabs and it worked good. Just don't know about plugging on these motors.

99blancoSS

iTrader: (115)

Pull the valve covers and check for lose rockers on each cylinder with the cam on its base circle. Get the valve covers off and inspect though, first step.

Intercooler2

iTrader: (24)

For sure. I wish I could find pictures of these broken stock rockers.

So anyone viewing this think I don't have a broken valvespring? Bent valves has me worried

01FbTaWs6

iTrader: (12)

pull the valve covers!! You will instantly know if you have a broken spring or dropped valve. its not hard to pull the valve covers your self.

Intercooler2

iTrader: (24)

I know and I will do that. Car runs so good I am hoping it is simple but doubt it.

If the top half has to come apart I'm going to have a local smooth the heads, flycut the pistons and add a better cam.

ls2 bait

iTrader: (11)

if you had a bad lifter you would likely know. and it would make constant noise. and likely a squeel when the roller locks up.

Intercooler2

iTrader: (24)

Thanks for that info.

I saw all the stories on the LS7 lifters and thought oh ****. Only other LS7 lifter I saw issue I saw was them bleeding down but couldn't find what that sounded like or did.

I'm hoping it is what the guy said up there where a rocker is busting loose. I read the fix for that is a $300 upgrade through Harland Sharp

JPH

iTrader: (2)

Number #7 exhaust always breaks 1st. Look where the roller part is in the rocker, and if it's broke, you see it all cocked and broken away from the cage portion/area where it sit in the rocker. Sometimes you will get some misfire codes and a ton of needle bearings will be in the oil stuck to the drain plug also. It will make rocker arm noise and sometimes chirping also.

Intercooler2

iTrader: (24)

Well the good news is the same as the bad.


I pulled the valve covers today. No needle bearings, no broken springs, pulled the #7 rocker and it looked great. Everything looked okay but I didn't pull all the pushrods. None looked funky so I thought I was spinning my wheels doing it. Now I'm worried!

Could it be one of the LS7 lifters?

TA1364

iTrader: (11)

Maybe make sure all your rockers are torqued to specs?

Intercooler2

iTrader: (24)

We torqued them when we put them on. None were loose when I put the socket on them today but I didn't retorque them. I will before I put the cover back on for good but that isn't it. What's some lifter and head gasket noises?