LS2 GTO Valvetrain/lifter noise
Thread Starter
Staging Lane
Joined: May 2013
Posts: 77
Likes: 0
From: OKC, OK
LS2 GTO Valvetrain/lifter noise So Ive had this intermittent valvetrain tick for awhile. Just today it turned into occuring all the time and now has a somewhat mettalic noise to it. It is rpm dependent and seems to go away above 2k rpm (or maybe the exhaust sound just drowns it out). It also appears to be coming from the top end and Ive ruled out accessories by running the motor with the belt removed. Im thinking its possibly a collapsed lifter, but not for sure. Anyone who wants to put in their 2 cents feel free... I plan to take off the valve covers tonight and check the rockers/pushrods/valvesprings. Is there any easy way to check the lifters without tearing the heads off to remove them?
Heres the mods on the car -
Stock LS2 shortblock - 105k miles
PRC 2.5 LS6 heads
Yellaterra rockers
LS7 lifters
MS4 cam
SW LT headers
All mods installed around 70k miles.
Heres a quick video I made -
Heres the mods on the car -
Stock LS2 shortblock - 105k miles
PRC 2.5 LS6 heads
Yellaterra rockers
LS7 lifters
MS4 cam
SW LT headers
All mods installed around 70k miles.
Heres a quick video I made -
Thread Starter
Staging Lane
Joined: May 2013
Posts: 77
Likes: 0
From: OKC, OK
Unfortunately I dont have a gauge, so cant give exact pressure, however the low oil light (which I believe activates below 10psi) has never came on. Is it possible to read oil pressure with a scan tool? I havent tried that yet. I was wondering if it could be bottom end also, but Ive never seen a rod knock that goes away with rpm, usually it just gets louder and sounds even worse, but anythings a possibility.
Thread Starter
Staging Lane
Joined: May 2013
Posts: 77
Likes: 0
From: OKC, OK
Heres a video I found with a near identical noise, turned out to be a lifter. Thinking Im going to pull the heads next weekend (Ill be out of town this weekend) and see how the lifters look. Worst case, its something bottom end wise and I need to pull the motor, oh well heads will already be off 
Heres the video Im referring to -
Heres the video Im referring to -
On The Tree
iTrader: (1)
Joined: Nov 2001
Posts: 108
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From: Republic of Texas - Houston Area
Yes you can read oil pressure with a scan tool ...
I'm betting on a bad lifter/cam lobe ... assuming oil pressure is still good. Your oil pressure will eventually go to nothing once the bypass valve gets stuck open from the metal shavings going through the pump. I've been down this road twice already ... If you're lucky you can get away with just replacing the following (inspect your cam bearings for trash and wear ... they'll "should" tell you what the rods and mains look like).
New oil pump
new cam
new lifters
double check your hardened pushrod length is correct
new springs fit for the cam chosen
valve job (optional but probably not needed if just installed 35k mi ago)
new timing chain
any new gaskets that didn't look reuseable during tear down
I'd recommend using Shell T6 5W40 oil with a good filter
This isn't an all inclusive list but it's a good start IMO
Good luck ...
I'm betting on a bad lifter/cam lobe ... assuming oil pressure is still good. Your oil pressure will eventually go to nothing once the bypass valve gets stuck open from the metal shavings going through the pump. I've been down this road twice already ... If you're lucky you can get away with just replacing the following (inspect your cam bearings for trash and wear ... they'll "should" tell you what the rods and mains look like).
New oil pump
new cam
new lifters
double check your hardened pushrod length is correct
new springs fit for the cam chosen
valve job (optional but probably not needed if just installed 35k mi ago)
new timing chain
any new gaskets that didn't look reuseable during tear down
I'd recommend using Shell T6 5W40 oil with a good filter
This isn't an all inclusive list but it's a good start IMO
Good luck ...
Thread Starter
Staging Lane
Joined: May 2013
Posts: 77
Likes: 0
From: OKC, OK
Thanks, really appreciate the good info, thats pretty much the exact list I had planned. Im hoping the collateral damage is minimal. As soon as it started making the noise on startup the other morning I turned it off and left it at home. Its not my daily, so its not a big deal to have it sit in the garage. Ill be tearing the heads off next weekend (Im going on a mini-vacation tommorow) and will update the thread as soon as I have the culprit out. Im still in a debate on what lifters to go with. Ive been told by quite a few to just get another set of LS7 lifters, but Ive seriously given thought to going with the Lunati/Morel's. Budget wise, I could only really afford their street performance ones (like $350 for the set) so I dont know if its really worth it.
