Questions ls3 has a knock - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Gtkilrss · 12-25-2013, 11:13 PM

2012 ss
L99 convertered to ls3
23x/24x 616 lift cam
3600 stall
Anyways at idle it will randomly make a sharp ping/knock.
Sound like you drop a wrench onto the frame kinda that kind of noise.
I'm not a noob and it isn't a normal lifter tick.

I'm thinking a lifter going out?

Mayb a rocker arm even tho they look ok.

Anyone had this issue and mayb could help me?

Thanks in advance

*mlee* · 12-25-2013, 11:21 PM

You can't really convert an LS3 to L99 without at least swapping pistons. L99 with DOD/VVT delete is more like it.

Assuming you already have LS7 lifters I wouldn't think that's your issue. The missing numbers on your cam specs leaves a little to the imagination, but it looks like a big cam. How long have you been running it?

Gtkilrss · 12-25-2013, 11:23 PM

Has 14,600 miles on it since cam swap. It's 231/242 I believe

Piccione Performance · 12-26-2013, 10:46 AM

I have seen 2 things that are consistent to what you are describing. I have seen the rocker bolts loosen up and cause the type of sound, pull the v/c's and retorque to make sure.
And the next one took a bit to find, it sounded like a faint rod knock from the bottom end, I found a high flow cat that had come apart and part of the metal core would intermittently rattle, the sound carried forward and it would knock and sound like a faint rod knock.
How theses help you find your noise.

Gtkilrss · 12-26-2013, 10:59 AM

I'll pull valve covers and check them again. I checked em not to long ago. It used to just make the sound every once in awhile and last night it was getting more frequent. Has no timing to to it it just does it. And I don't have cats

*mlee* · 12-26-2013, 11:35 PM

Maybe a video of the sound would help someone figure this out for you. Rocker bolts way be worth a check as mentioned. That cam is big but not too big.

Gtkilrss · 12-29-2013, 06:27 PM

Soon as I get back into town I'm gonna check converter bolts. Iv heard of a couple instances of that as a problem

DarkCry956 · 12-29-2013, 06:44 PM

My converter bolts came loose once and it wouldn't sound like a knocking sound it was a loud screech/rattle at high RPMs and sometimes during shifts.

*mlee* · 12-29-2013, 06:44 PM

Quote:

Originally Posted by Gtkilrss

Soon as I get back into town I'm gonna check converter bolts. Iv heard of a couple instances of that as a problem

Fingers crossed that's it...

Gtkilrss · 12-29-2013, 10:37 PM

Quote:

Originally Posted by mlee

Fingers crossed that's it...

Yea sane here. If not guess time for big motor

12-25-2013, 11:13 PM	#1
Gtkilrss Drives: 2016 SS Join Date: Jan 2013 Location: Blackwell, OK Posts: 400	Questions ls3 has a knock 2012 ss L99 convertered to ls3 23x/24x 616 lift cam 3600 stall Anyways at idle it will randomly make a sharp ping/knock. Sound like you drop a wrench onto the frame kinda that kind of noise. I'm not a noob and it isn't a normal lifter tick. I'm thinking a lifter going out? Mayb a rocker arm even tho they look ok. Anyone had this issue and mayb could help me? Thanks in advance __________________

12-25-2013, 11:21 PM	#2
mlee CamaroFans.com Drives: ZLE & ZR2 Join Date: Oct 2008 Location: Conroe, TX Posts: 37,507 View My Garage	You can't really convert an LS3 to L99 without at least swapping pistons. L99 with DOD/VVT delete is more like it. Assuming you already have LS7 lifters I wouldn't think that's your issue. The missing numbers on your cam specs leaves a little to the imagination, but it looks like a big cam. How long have you been running it? __________________

12-25-2013, 11:23 PM	#3
Gtkilrss Drives: 2016 SS Join Date: Jan 2013 Location: Blackwell, OK Posts: 400	Has 14,600 miles on it since cam swap. It's 231/242 I believe __________________

12-26-2013, 10:59 AM	#5
Gtkilrss Drives: 2016 SS Join Date: Jan 2013 Location: Blackwell, OK Posts: 400	I'll pull valve covers and check them again. I checked em not to long ago. It used to just make the sound every once in awhile and last night it was getting more frequent. Has no timing to to it it just does it. And I don't have cats __________________

12-26-2013, 11:35 PM	#6
mlee CamaroFans.com Drives: ZLE & ZR2 Join Date: Oct 2008 Location: Conroe, TX Posts: 37,507 View My Garage	Maybe a video of the sound would help someone figure this out for you. Rocker bolts way be worth a check as mentioned. That cam is big but not too big. __________________

12-26-2013, 10:46 AM	#4
Piccione Performance Drives: 2010 2ss/rs & 2014 Stingray Join Date: Aug 2013 Location: Phoenix Posts: 124	I have seen 2 things that are consistent to what you are describing. I have seen the rocker bolts loosen up and cause the type of sound, pull the v/c's and retorque to make sure. And the next one took a bit to find, it sounded like a faint rod knock from the bottom end, I found a high flow cat that had come apart and part of the metal core would intermittently rattle, the sound carried forward and it would knock and sound like a faint rod knock. How theses help you find your noise.

12-29-2013, 06:27 PM	#7
Gtkilrss Drives: 2016 SS Join Date: Jan 2013 Location: Blackwell, OK Posts: 400	Soon as I get back into town I'm gonna check converter bolts. Iv heard of a couple instances of that as a problem __________________

12-29-2013, 06:44 PM	#8
DarkCry956 Drives: 2011 Camaro 2SS/RS Join Date: Oct 2011 Location: Texas RGV Posts: 794	My converter bolts came loose once and it wouldn't sound like a knocking sound it was a loud screech/rattle at high RPMs and sometimes during shifts.