JoeMack

iTrader: (18)

Does anyone know the procedure for installing stock rocker arms on an LS1? I thought that you just torque, rotate the motor a few times and then re-check. Now I am hearing that there is a recomended procedure to follow. Thanks

GregWS6&z28

iTrader: (8)

all ive heard is torque to 22ftlbs, rotate, and check, yep

777

iTrader: (21)

I don't know where it is but you tighten certain valves then rotate 360 and tighten the rest.

Tommy Tucker

Jim's LS1howto will have all the details.

SideStep

Per the service manual.... and the only way I have ever done it.


6. Rotate the crankshaft until the number one piston is at top dead center (TDC) of the compression stroke. In this position, cylinder number one rocker arms will be off lobe lift, and the crankshaft sprocket key will be at the 1:30 position. The engine firing order is 1,8,7,2,6,5,4,3. Cylinders 1,3,5, and 7 are left bank. Cylinders 2,4,6, and 8 are right bank.

7. With the engine in the number one firing position, tighten the following valve rocker arm bolts: Tighten

.....(1) Tighten the exhaust valve rocker arm bolts 1,2,7, and 8 to 30 N·m (22 lb ft).
.....(2) Tighten the intake valve rocker arm bolts 1,3,4, and 5 to 30 N·m (22 lb ft).

8. Rotate the crankshaft 360 degrees.
9. Tighten the following valve rocker arm bolts: Tighten

.....(1) Tighten the exhaust valve rocker arm bolts 3,4,5, and 6 to 30 N·m (22 lb ft).
.....(2) Tighten the intake valve rocker arm bolts 2,6,7, and 8 to 30 N·m (22 lb ft).

Moparnos (The SLP Guy)

iTrader: (55)

correct

JoeMack

iTrader: (18)

Thanks for the info.

JRracing

iTrader: (35)

Good info. I got this a few weeks ago on another thread.

MCW02ZO

SideStep, I'm a newbie and came across your post on rocker arm assembly and have a couple of questions. Planning on replacing the valve springs on my 02ZO6 because of all of the issues I've read.
1. What's the best way to rotate the engine manually since it is so crammed under the hood?
2. When you say #1 TDC is when rockers are off load lift they should both be in the up position correct?
3. DO the rockers need to be re-torqued after the engine is run?
4. If your familiar with the spring issue on these can you recommend high quality replacements?

Thanks for the help and I appreciate any info. you can provide.

godspeed01

hi tehre

whats the deal with preload then if we just crank down to 22ftlbs????

Rickenbackerman

iTrader: (1)

This is the way to do it. If you just crank down on the bolts without following this procedure, the valvesprings will load the bolts up early on the valves that are open and won't have good thread engagement. You could possibly strip the rocker bolt threads. This way, the valves are closed when you tighten the rocker bolts and the only thing loading up the bolt is the lifter spring.

ZeeOSix

Answers:
1) Go to Autozone or similar and get a 45 degree offset box wrench (24 mm or 15/16", both will work) to turn the motor over using the crank bolt. I found the wrench a Autozone has the perfect offset to clear the damper.

2) Yes. Cyl #1 should be at TDC on the compression stroke.

3) No.

4) PAC 1218 or PAC 1518 springs are used by many with good results with the stock cam.

gMAG

iTrader: (1)

I prefer to torque rockers only after turning the engine to tdc/firing stroke for each cylinder in turn. This way, I know that the spring pressure against which the rockers are tightened, is exactly the same for each rocker.

ZeeOSix

The procedure that GM calls out in the Service Manual ensures no spring pressure is on any rocker arm during tightening.

SOMbitch

iTrader: (8)

And don't forget to use blue loctite.

ls1 Statesman

If your running roller rockers like YT's etc, need to torque the rocker bolts when both valves are closed on each cylinder,not the GM procedure.

ZeeOSix

When people talk about "pre-laod", they are talking about how much travel the lifter plunger is "pre-loaded" by the pushrod when the rocker arm is bolted down. The rocker arm is always torqued to 22 ft-lbs, regardless of how much per-load the lifter has.

ZeeOSix

It's not called out in the Service Manual, and almost everyone doesn't use any kind of thread locker on the rocker arm bolts.

gMAG

iTrader: (1)

If there was no spring pressure, then no valves would open while performing the GM method. Am I missing something here?
The GM method is a batch type/ballpark procedure. It's better than LS1HowTo, but any valve position other than tdc/firing stroke would translate to varying spring pressures from cylinder to cylinder, and from intake to exhaust valves, during the torqueing process. The crank should be rotated 90 deg (not 360) for each cyl, in firing order, for tdc to occur.
In a similar way to the tdc method, I could make sure that each valve was operated to exactly the same height before torqueing. In this way, the spring pressures would also be the same for all.
If the GM method fits the bill, that's fine. I prefer the method given in the YT install.

ZeeOSix

But the GM procedure puts the rocker you're torquing down with the lifter on the cam base circle and the valve fully closed.

I wasn't sure about it myself until I made up this chart (attached) that verified the GM procedure does indeed put them all in the fully closed position when you torque them down. The chart shows this when you compare it to the GM procedure to correlate it all together.