TipsyMcStagger

iTrader: (1)

First time doing a cam swap on an LS. Engine is an LS2. It's on a stand and has not been run in at least two years. I installed the cam about a year ago but left the rocker arms off, so the engine wouldn't sit with the valve springs compressed.

Cam is custom grind by Tick (though it seems to be almost identical to the LS2 Street Heat Stage 1 V2). When ordered, I asked Martin about push rod length. He said 7.4" would be fine. I don't have a pushrod length checking tool but I've read if I tighten the rocker to zero lash (which is pretty much a wag), it should take about 3/4 of a turn to reach 22 ft lbs.

I have the #1 Cyl at TDC on compression stroke. I'm following this method:

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

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

Rotate the crankshaft 360 degrees.

Tighten the following valve rocker arm bolts:

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

I haven't gotten consistent results. I've loosened a few and retorqued them because several took way more than 3/4 turn to achieve 22 ft lbs. On this latest pass I've gotten six of eight rockers tightened to 22 ft lbs at approx 3/4 turn. But the Exhaust on #7 took 2 3/4 turns and the Intake on #4 took also took 2 3/4 turn. On earlier attempts, a few took more than 3 turns and one was nearing 4 turns before I stopped.

I'm afraid I'm going to screw something up. I'm sure the lifters are not pumped up after sitting for so long. And I had to physically push each lifter down onto the cam when inserting the push rods (but I suppose that's by design?). Should I loosen them all, prime the engine and start over?

Looking or some help.

Thanks very much.

Tipsy

99wssixm6

iTrader: (3)

I always just click them to 22 lbs and rotate the engine a few times and go thru them again. Never had a problem.

TipsyMcStagger

iTrader: (1)

Thanks, but I'm wondering why the disparity between individual valves? And I was hoping to verify that 7.4" is the proper pushrod to be using with this cam (albeit using a less than accurate method).

I just primed the engine (using this method) and will try to tighten the rockers again.

Tipsy

TipsyMcStagger

iTrader: (1)

Success! Okay, I spent all day tightening 16 bolts to 22 ft lbs, but hey...I'm in no hurry and I don't want to make a costly mistake.

I primed the engine until oil was flowing from the pushrods onto the rockers and tried again using the above method. This time, most were just about 3/4 turn from zero lash to 22 ft lbs with only a few that were slightly less (heavy 1/2 turn) or slightly more (light full turn). And I attribute the variation to the non-precise method of setting zero lash.

I feel comfortable that 7.4" pushrods are correct. I hope this will help someone down the road.

Tipsy

LQ4-E39

iTrader: (7)

Thanks for taking the time to document this Tipsy. I'll be going through this process this week on the fresh motor.

TipsyMcStagger

iTrader: (1)

Glad to, Norb. These forums are a great tool. Too many times people ask a question or describe a problem and never return to post a resolution. I don't want to contribute to that.

Tipsy

CAMSTER

iTrader: (10)

I don't use a torque wrench on small bolts unless I need to get screwed.

Learning when is tight by felling the bolt strength is the way to get it done.

Must torque wrench are not very accurate in low settings and malfunction as much as 60% of the times.

SHovV

iTrader: (1)

That's why it's ways best to use good quote tools