I was playn around today and left astop light revved it pretty good and when it idled down had a top end tapping sound .........well i freaked out pulled over and went to check it out when all the sudden it just went away and it purs like a kitten ? No power loss ! oil pressure never didnt anything different still hits 65 when u rev it up .

What the hell was it?

 

Rockers chatter sometimes. Might have not been anything really..

 

I Mean It Was Loud And 2 Blocks Later Went Away ?

 

My car does this too , but after idleing a few minutes it quiets down. I 'm running Harland Sharpe rockers and they seem to be a little more noisier than the stock rockers anyhow .

 

i mean if i spun it it would be shot right

 

i would think a bearing would be knocking all the time and go up with rev's. these engines are just noisy sometimes.

 

A lifter may have been slightly stuck momentarily. What kind of oil are you using?

 

a bearing would give you a "clanking" noise and increase as you hit the throttle... If it's not doing it anymore your probably fine... otherwise something could be going on in your valvetrain...

 

its 20 50 mobile one i am running that because tsp told me it would help with vavle train noise

 

Sounds like a lifter to me. You may have one bleeding off a little at high RPM which would explain the temporary ticking noise that went away once the engine was idled down and had a chance to build pressure back up in the lifter. Try revving the motor up again similar to how you did before and see if it does it again.

 

20w50 is way thick

 

I just recently learned that a spun bearing doesn't always make noise all the time. I just pulled my motor last month for a refresh because it made an intermittant knock at higher rpms under load, turns out it had spun a bearing. It made NO noise at all under 3500 RPM and had great oil pressure. I never would have heard it until it was too late had I not had it on the dyno where we could hear it under the hood while it was under load. Turns out it had spun the #1 rod and the #2 main was torn up pretty bad but stayed in place.

 

It did i again tonight . revved it up took off came to a stop clanking . let it set running 3 minutes went away . still a very very faint sound but nothing like before

 

Yea, 20w-50 is on the heavy side for LS1's and their direct engine block descendants. Stick with 10w-40, 10w-30, or 5w-30 if you'd like.

 

makes me think it'll progressivly get worse

mine did about 10 runs on the dyno with a spun bearing till we finally decided to give it a rest before a piston shot out the side of the block

mine had some clanking going on... pulled apart the valvetrain, found 3 bent pushrods... dug deeper and found a failed lifter... dug even deeper and found the spun bearing and rod knock...

bad news = engine was gonna need some work
good news = got a new, built engine

 

its the 20-50. its too thick to keep the lifter pumped up. the hardcore factory guys run 5-30. change it over to 10-30. then see what it does. its cheap and easy to diagnose.