[Z06] LSx Rocker Arm Failure
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
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.
Pro
Joined: Sep 2008
Posts: 713
Likes: 2
From: Tennessee
This happens because people are using springs that have too much opening pressure. Stock rockers are only supposed to handle 400#. A very common spring out there has 450# of opening pressure. Really wears on the rocker tip.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
When I swapped my valve springs I also did the Comp Cams trunnion kit on the rocker arms ... cheap insurance. There have been cases where the OEM rocker arm bearings have failed with the stock cam/springs.
Pro
Joined: Sep 2008
Posts: 713
Likes: 2
From: Tennessee
That's why PAC 1218 or 1518 beehive springs are a good replacement spring for the LS6. Their open pressure is basically within a few lbs of the stock LS6 springs @ ~320 lbs.
When I swapped my valve springs I also did the Comp Cams trunnion kit on the rocker arms ... cheap insurance. There have been cases where the OEM rocker arm bearings have failed with the stock cam/springs.
When I swapped my valve springs I also did the Comp Cams trunnion kit on the rocker arms ... cheap insurance. There have been cases where the OEM rocker arm bearings have failed with the stock cam/springs.
Drifting
Joined: Jan 2010
Posts: 1,447
Likes: 1
From: Katy TX
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.
Race Director
Joined: Apr 2004
Posts: 16,135
Likes: 5
From: Newberry FL
Cruise-In VIII Veteran
St. Jude Donor '07
Interesting thread for sure! Right now I am running a stock motor (LS6) with 918 springs, COMP CAM (stock length) push rods and stock rocker arms. I do plan to CAM the car and run a dual spring setup, but what is a good replacement to the rocker arm, if I do not go this route?
Micah
Micah
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
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Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
Interesting thread for sure! Right now I am running a stock motor (LS6) with 918 springs, COMP CAM (stock length) push rods and stock rocker arms. I do plan to CAM the car and run a dual spring setup, but what is a good replacement to the rocker arm, if I do not go this route?
Micah
Micah
Race Director
Joined: Apr 2004
Posts: 16,135
Likes: 5
From: Newberry FL
Cruise-In VIII Veteran
St. Jude Donor '07
Running a YELLA TERRA RA require different push rods or a high valve cover? Or is just a direct replacement and torque to the specified specs?
Last edited by mph1972; Jun 11, 2012 at 02:22 PM.
Thread Starter
Former Vendor
Joined: Feb 2007
Posts: 2,572
Likes: 1
From: Austin Texas
Yella Terra Rockers will require some clearencing or they will tap the valve covers. Also, the pushrods will change and need to check for proper length with a pushrod checker.
Race Director
Joined: Apr 2004
Posts: 16,135
Likes: 5
From: Newberry FL
Cruise-In VIII Veteran
St. Jude Donor '07
Pro
Joined: Apr 2009
Posts: 734
Likes: 2
From: Mt. Airy MD
If I ever buy another C5Z I'd go that route instead of paying someone else to do it. Watching the vid takes the mystery and fear out of it.
Sorry no link but it should be an easy find with a search.
Race Director
Joined: Apr 2004
Posts: 16,135
Likes: 5
From: Newberry FL
Cruise-In VIII Veteran
St. Jude Donor '07
Then why would I have to get a different length pushrod? (see post above?) I am not planning on doing any serious modifications, CAM down the road, but my tuner (he designed the CAM) informed me today that the YELLA TERRA rocker arms are fine.
Le Mans Master
Joined: Mar 2002
Posts: 5,955
Likes: 161
From: PNW
Because apparently the Yella Terra rocker arms don't have the same exact dimensional profile as the stock rocker arms. Once you change that, different length pushrods will be needed to obtain the same lifter pre-load.
