I was driving my Z-28 to night and just messing around with a buddy in his Z06, i did hit the rev limiter in first gear but didnt hear any strange noises. Latter on down the road when i slowed down, and the rpm droped it felt and sounded like i had a miss but there was no knocking and it started to have black smoke come out of the exhaust when i reved the engine. I shut the car off and about an hour later i started the car again and everything seemed fine. No smoke, no misses, but a strange rattle. It ran fine for a few blocks and started to smoke and miss and pop. I had no chioce but drive back to base with it running like azz but on the way i did get on it a few times and above 3k rpm it seams to run fine and is just as strong as ever, but when the rpm drop is runs like **** again. I dont know and the only thing i thank can be the issue is the pushrods. Any help would be appreciated.

V/R
Chris

 

It is quite possible that you do have a bent pushrod, that same thing happened to me recently. i just let it go at the time like yourself, but eventually the pushrod broke in half causing me lots of trouble.

Although it didn't make much sense to me at the time I now believe weak valvesprings or lifters could have bent the pushrods at high rpms. taking off the valvecovers to the heads will give you a better indication of valvetrain damage. Hope that helps.

 

thanks im pulln the valve cover in the morning

 

i would say you have a bent push rod/rods also. sometimes you can get lucky and tag the limiter and not bend them but some people are more fortunate than others.

 

i pulled the drivers side cover and everything looked fine but i went a head and pulled a rod out and it came out strait, but there are some strange scratches on the side of the rod.

 

You cant check for a bent pushrod by looking at it. Find some glass and roll them across the glass. A buddy of mine had an A4 camaro, and when he pulled his pushrods out, they looked fine but when you rolled them across glass, you knew immediately they were slightly bent.

Its only 125 dollar insurance brand new. It is definitely worth your time and money to replace them with hardened.

And definitely dont let it go, I pulled a pushrod out of my car that was shaped like an S and it machined part of the pushrod guide in the head.

 

im planning on replacing them but i dont see how a bent rod would let the motor start just fine then slowly transition to running like poo. and then at higher rpm it seems to be fine. the mysteries of the good ole ls1.

 

I have tagged the limiter quite a few times with the stock pushrods and none came out bent, but when I did my cam/valvespring swap I got the hardened TSP chrome molly pushrods. Like someone else said, cheap insurance.

 

Just kidding, out of curiosity I grabbed my stock pushrods and a few of them are bent when I roll them on a flat surface. One is kind of discolored towards the top, not sure what thats all about.

 

overheated metal. Some sort of oil lubrication problem/wrong seating. The friction got to the metal and got to hot thus changing the color of the metal. Sell it to some rice saying they are "titanium tiped" push rods lol.

 

hahaha

 

i just ordered the slp chrome moly stock length pushrods P/N 003509.