LSx Rocker Arm Failure
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
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From: Austin Texas
LSx Rocker Arm Failure
I had a customer come in to the shop last Saturday for a rattling sound from the engine. After further inspection, found that the #4 rocker arm failed. This was a heads/cam C5Z with the stock rocker arms. As part of preventative maintenance, the rocker arm bearing should be replaced.
C5Z Rocker Arm Failure
The stock rocker arms contain 33 bearings on each side and that is a total of 1056 bearings for all rocker arms. In this instance, none were in the head and all have drained to the oil pan. Now, from there, the magnetic drain plug will only capture a few. The other can be floating who knows where. This is cheap insurance and once these fail, they can mess up the valve stem and retainer.
RPT Rocker Arm Rebuild
I have seen occurances were this can trash an engine and have seen it. The rocker has to be replaced since it was destroyed and after the repair, the engine was nice and quiet.
We have the rocker trunion upgrades in stock and offer the core swap, for no down time.
C5Z Rocker Arm Failure
The stock rocker arms contain 33 bearings on each side and that is a total of 1056 bearings for all rocker arms. In this instance, none were in the head and all have drained to the oil pan. Now, from there, the magnetic drain plug will only capture a few. The other can be floating who knows where. This is cheap insurance and once these fail, they can mess up the valve stem and retainer.
RPT Rocker Arm Rebuild
I have seen occurances were this can trash an engine and have seen it. The rocker has to be replaced since it was destroyed and after the repair, the engine was nice and quiet.
We have the rocker trunion upgrades in stock and offer the core swap, for no down time.
Team Owner
Joined: May 2001
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From: Western NY
I had a customer come in to the shop last Saturday for a rattling sound from the engine. After further inspection, found that the #4 rocker arm failed. This was a heads/cam C5Z with the stock rocker arms. As part of preventative maintenance, the rocker arm bearing should be replaced.
Tech Contributor
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From: Dyer, IN
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Le Mans Master
Joined: Mar 2002
Posts: 5,955
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From: PNW
... so what's with the LS7 having rocker arm bearing failures? Didn't GM learn a lesson and not use the captured needle bearings in the LS7? 
http://forums.corvetteforum.com/c6-z...ngs-issue.html
Le Mans Master
Joined: Jun 2002
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From: In the pit, trying to love someone.
... so what's with the LS7 having rocker arm bearing failures? Didn't GM learn a lesson and not use the captured needle bearings in the LS7? http://forums.corvetteforum.com/c6-z...ngs-issue.html
Le Mans Master
Joined: Mar 2002
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From: PNW
http://forums.corvetteforum.com/1564885933-post5.html
Anyone have a photo of the new GM "caged" rocker arm bearings?
Intermediate
Joined: Jun 2011
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It has been discussed several times here on the CF, that the OE rocker trunnions are NOT designed for use with cams that have more lift than a stock cam. It's NOT a question of preventive maintenance, that says the OE trunnions should be replaced with the CompCams kits, rather the OE trunnions HAVE to be replaced when a cam with higher lift numbers than stock, has been installed in the engine. An alternative would also be an aftermarket full roller rocker....
I can agree that waxers and trailer queens can skip this upgrade. People who drive these cars the way they were meant to be driven, however, should consider the trunnion upgrade as reasonable and cheap insurance. Yes, even if they're otherwise stock and yes, especially so if they plan on upgrades as you've noted.
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
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From: Austin Texas
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
LS1/LS6/LS2 and LS3 Exhaust Rockers are the same. The LS7 uses a 1.8 ratio rocker and is different.
Thread Starter
Former Vendor
Joined: Feb 2007
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From: Austin Texas
Le Mans Master
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From: In the pit, trying to love someone.
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
The OEM rockers are not caged. Thge caps are pressed in and only in place by friction. Not sure id SDPC is offering upgraded rockers. The 2012 Camaro ZL1 has the some rockers GM has been using since 1997.