Procedure For LS1 Rocker Arm Install?
Procedure For LS1 Rocker Arm Install? 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
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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).
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).
Last edited by SideStep; Mar 23, 2006 at 09:32 AM.
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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.
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.
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).
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).
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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.
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.
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.
Last edited by ZeeOSix; Feb 29, 2012 at 03:02 PM.
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.
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The procedure that GM calls out in the Service Manual ensures no spring pressure is on any rocker arm during tightening.
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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.
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.
Last edited by gMAG; Mar 1, 2012 at 01:04 AM.
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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.