intermittent Knocking sound 06gpgt

**black06gt** · 01-27-2016

well i guess this weekend i will be stripping it down. gonna try lifters, rods and rockers that i have from a previous build. maybe that will get rid of this crap noise. anything else guys? second third and forth opinions?

**Scottydoggs** · 01-27-2016

id get it knocking again, then listen for the side its on. shut it down while its knocking then take that cover off. look for the really loose rocker.

once you can see its a loose rocker id open it up and do lifters.

**black06gt** · 01-27-2016

alrighty thanks man

**black06gt** · 01-27-2016

i did try the screw driver to the ear deal last night. it sounds like its coming more from under the intake and louder on the back side not real definitive though.

**Scottydoggs** · 01-27-2016

pop em both off. looks like they are coming off anyways.

i just like to see a issue first hand before i tear open anything.

**black06gt** · 01-27-2016

right. ill try it again to see if i can narrow it down some more

**CrazyGuy03** · 01-27-2016

Harbor freight has a stethoscope for @ $10
works awesome

**Grand prix 06** · 01-27-2016

What about a cracked or busted piston skirt that will make that noise also i have seen them come and go on that kind of noise.

**black06gt** · 01-27-2016

Taking it to a dealer on saturday. Friend of the family works there. Did it end up being a broken skirt on the one you seen come and go?

**black06gt** · 01-27-2016

Did it again today but not when I got work and quit 45 seconds after getting home. Anyone selling an l32? Lol

**CrazyGuy03** · 01-27-2016

http://www.grandprixforums.net/threa...31#post1408031

**J57ltr** · 01-27-2016

Almost sounds like the balance shaft is hitting something. It's definitely something at half engine speed so it's got to be something in the related to the cam.

**CrazyGuy03** · 01-27-2016

You know lifter tick when you hear it. That's a knock for sure

**black06gt** · 01-27-2016

Plus it goes away with rpms or just let it idle warm or cold doesn't matter.

**black06gt** · 01-27-2016

Like a long red light or just parking it will go away within a minute. I have not a clue. If it does it I can shut it down and start it right back up and it's gone

**Grand prix 06** · 01-27-2016

I had a 3100 do that to me

**J57ltr** · 01-27-2016

I am not saying it's a lifter, but the sound is not as fast as engine speed the only other possibility is something cam driven.

**b4black** · 01-27-2016

I haven't watched the videos, but I had a nasty sound thst came and went like you describe. It was a cracked flexplate. There's an inspection plate under the transmission. That it off and look inside. You might see cracks at the "windows". Its a somewhat common problem.

**black06gt** · 01-27-2016

Was kinda hard to see in there. Only thing I seen were a couple small lines coming down from the middle of it but I couldn't tell if they were cracks or not.