Rocker install, rotate crank/engine?
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Rocker install, rotate crank/engine?
So tomorrow I will swap out my stock trunnion bearings with new BTR Trunnions and,,,,,,,,,, in looking in my 2005 GM service manual it talks about rotating the engine like I used to do on my L98...
But when we installed my buddy's Supercharger cam in his 2006 C6 this past winter (700-rwhp w/meth), he did not rotate the engine, he just torqued the stock rockers down to 22-ft/lb......
It would save time for sure to just torque them down, any consensus on this?
I could see that, in doing the rotation, you will load each rocker in the relaxed position, and maybe get some peace of mind on the rocker being under no stress during the TQ procedure
But when we installed my buddy's Supercharger cam in his 2006 C6 this past winter (700-rwhp w/meth), he did not rotate the engine, he just torqued the stock rockers down to 22-ft/lb......
It would save time for sure to just torque them down, any consensus on this?
I could see that, in doing the rotation, you will load each rocker in the relaxed position, and maybe get some peace of mind on the rocker being under no stress during the TQ procedure
Drifting
Joined: Apr 2011
Posts: 1,540
Likes: 79
From: Houston, Tx
St. Jude Donor '11-'12-'13-'14
It would not be a bad idea to spin it a few times and recheck it. Some are up on the lobe all the time. The stock rockers are easy but I had some Crane 1.8 adjustable on an LS2 and it was a PITA to get them right.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Thanks, I've done this a dozen times but not on an LS engine, I like the fact that the lash adjustment is a no brainer on the stock rockers,
If the crank bolt is accessible in order to turn the crank, then I will spin it.
If the crank bolt is accessible in order to turn the crank, then I will spin it.
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Started at 8:00am, finished at 11:15am, easy and simple mod.
Next is a new Brian Tooley Cam, Double Springs, Push Rods, ATI Damper & ARP Bolt, new timing chain, and Peak Speed radically ported intake, will begin in a a couple of weeks..,,, done in time for Funfest
Next is a new Brian Tooley Cam, Double Springs, Push Rods, ATI Damper & ARP Bolt, new timing chain, and Peak Speed radically ported intake, will begin in a a couple of weeks..,,, done in time for Funfest
Last edited by LD85; Aug 22, 2015 at 02:31 PM. Reason: time
Safety Car
Joined: Feb 2007
Posts: 4,684
Likes: 107
From: Opelika Alabama
just got to take your TIME and follow Crane's instructions, I've got the 1.7 golds
Thread Starter
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Safety Car
Joined: Nov 2000
Posts: 4,549
Likes: 30
From: Shenandoah Valley Virginia
I never spun the engine when changing valve springs on my track car. Just install the rockers and torque to proper spec. Then spin the engine a few turns using the starter but not firing, and retorque. After 4 sets of springs - never had a problem.
Melting Slicks
Joined: Aug 2006
Posts: 2,475
Likes: 97
From: KY/TN
St. Jude Donor '13-'14-'15-'16
Rotating the engine so that the lifter is on the base circle instead of the ramp allows for the rocker arm to be torqued accurately and allows for correct preload. There are several threads where rocker pedestals broken off because of improper torque values.
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Le Mans Master
Joined: May 2000
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Likes: 12
I agree with you. If you don't rotate the engine you are torquing against the valve spring as well as well as putting undo stress on the threads whole torquing. When I put my 1.8 YTs in this year I did rotate the engine to get the lifter on the base of the cam.