I have been experiencing some funny tapping that comes and goes. seems like around 2k it will start then if i let off, bring the rpm's down or slam my foot into it, seems to go away. i thought it would be an exhaust leak because of it coming and going but everything is tight. any suggestions?

 

bent pushrod or a bad lifter is my guess.

 

I'm chasing the same thing. I change lifters, head gaskets ,header gasket ,had the heads reworked with .015 removed, clutch kit with flywheel,rocker arm trunions and changed pushrods length a few times. Good luck because I still haven't fixed mine. Been chasein it for months. I'm gonna check the gasket in the camshaft retaining plate next. If that's not it I'm pulling the engine.

 

yeah its killing me, i don't even care to drive the car when its like this haha. but yeah it comes and goes. i figured if it was a pushrod it would be constant. but who knows i'll keep trying. if anyone finds anything let me know. thanks

 

Keep looking and please post any findings. I'm experiencing a similar noise. It started many miles ago but has been getting progressively worse. I'm now at 100k and not sure what I am dealing with. The noise isn't there at a cold start up and will start within 30 sec or so of the engine running. I get a lot of clatter under 2k RPM when driving until the engine gets up to temp then it seems to go away for the most part. I'm thinking bad lifter but I'm looking for some input from anyone who has had it and fixed it before I open up the motor.

-Brian

 

Mine does it as well. I just figured it was piston slap since its mainly when the motor is cold.

 

Wait, you said it doesn't do it at start up, but goes away when the engine is warm? When my stock ls1 was cold it made a crazy loud clacking sound until it warmed up. My built engine does it, but s10 also does it. The rest of the time they make a small sewing machine noise. All these ls1's make noise.

 

I've had piston slap when its cold from the time I've owned the car but this is a different noise. From other threads I've read it sounds like lifter(s) and it seems like a common problem.

 

Yep. Right at start up its fine, give it a bit and it starts, then it will quiet down after it is up to temp. In between it sounds like what someone else called the sewing machine from hell. I've changed oil viscosities and it hasnt really made it better or worse it just changes when the noise is louder.

 

I have a similar noise coming from the driver side, I thought it was an exhaust leak but I couldn't find any.

 

I have the same exact issue, only does it when its warmed up a bit, sounds like its coming from the center of the engine but more towards the drivers side. Did header gaskets, looked around for an exhaust leak, nothing. I'm gonna pull off the valve cover here soon and look for anything weird. I don't have much experience at all with engine internals though