What's this noise?
 

I've got a 1996 SS with 39,XXX miles on it and I've got a bad knock/peck/tick/SOMETHING.

The closest thing I can compare it to is a sewing machine.. I am guessing that it's a very common LT1 problem due to the fact that my car has low miles but I admit that it was really BEAT on for about 10,000 miles of it's life. (26,XXX to about 36,XXX)

I do not drive the car very much at all but the noise developed sometime when the car was my DD. I am now motivated to fix the car up and correct my problems. I thought the noise was rod knock but I'm not so convinced that it's not in the valvetrain.. I'm an engine NEWBIE and need some advice.

Today I went out and cranked the car after a very cold period of weather and the noise was NOT THERE! Oil pressure built as usual and the car sounded as it should.. for about 45 seconds. I went in the house getting some stuff together and came out and it was singing to me again. The noise is most prevelant at 1,000 to 2,000 RPM's and will tick approx. 35 times in a 10 second period at 1,000 RPM's and approx. 55+/- times at 1,500 RPM's. If you rev the engine to about 3 grand it will start ticking as the R's drop from 2,000 to 1,000 and you can hear it approx. 7 times as the RPM's naturally drop to normal idle on my car - about 900.

Any help/advice is appreciated. Is it a bent pushrod? bad valve? bad rocker? trashed rod bearing? I know you will have more questions for me, so just ask.

There is a possibility that this engine was ran for a period of time (in minutes, not miles) without any oil pressure.

THANKS FOR THE HELP - I DID A SEARCH BUT THE TOPIC SEEMS VERY BROAD

I would guess most likely exhaust leak... make sure the bolts on the exhaust manifolds are tight and there are no hole in the exhaust anywhere.

Next I would guess rocker arm, but fairly unlikely that a rocker arm came loose with so few miles. I will practically gaurantee you its not a rod, you would know something was wrong.

I appreciate the info.. but it definetly does not sound like an exhaust leak. It's worth checking out though, I'll make sure it's not..

My original assumption was a rocker arm but I've been second guessing that. I hope it's not in the bottom end.

I'll just build the valvetrain and buy a H/C package and bolt it up and see if it persists!

any more?

it is really hard to guess on a tap/tick/knocks are kinda hard to narrow down on the internet... perhaps someone a lil more knowledgable can help ya track it down. Its not that hard to get the valve covers off and check the rockers though.

I had the same problem on my car with 74k didn't start till around 70k. I had just recently tore it down to just the short block for a H&C and The only problem I notice was my exhaust gasket was blown on 1 side other than that my rockers and push rod were all good. I would just pull the covers and find out.

what would a bad rocker look/act like.

hahaha let the bashing begin.. i said i was an engine internal noob

That would be really loud ticking. I would go with an Exhaust leak.

Rocker arm will be pretty loud and not a ticking noise... kinda like knocking your knuckle against thick metal. Best description I can give :jest:

you should be able to listen and tell which side of the engine it is coming from... once you conclude that check that sides manifolds and if that aint bad then pull off that valve cover. If one of the rocker arms is loose enough to wiggle it more than a couple thousanths of inch then that would be your problem.