Main torque specs
Thread Starter
Staging Lane
Joined: Jun 2005
Posts: 77
Likes: 1
From: New Orleans
Main torque specs Got my ls1 on the stand and about to swap the oilpan and windage tray, I was just wondering what procedure to follow? Are these bolts torque to yeild and should i use some type of thread locker? What are they supposed to be torqued to?
Joined: Nov 2001
Posts: 3,043
Likes: 0
From: Texas and Qatar
You shouldn't need to replace them unless they have been used a few times. The bolts are not torque-to-yield, but are torqued in an angle-torque procedure.
All bolts torque to 16lb ft while maintaining forward thrust on the crankshaft (prying the crankshaft forward when doing the #3 main cap), from center working outward in a spiral, do all 13mm first in pairs, then all 15mm headed bolts.
Then torque 13mm main cap bolts to 80 degrees of rotation following a similar pattern as above.
Finally torque 15mm studded main cap bolts to 53 degrees of rotation.
My angle torque wrench logs the actual torque and it usually shows 58-62lb ft when I angle torque main cap bolts, but I would still use the above procedure.
All bolts torque to 16lb ft while maintaining forward thrust on the crankshaft (prying the crankshaft forward when doing the #3 main cap), from center working outward in a spiral, do all 13mm first in pairs, then all 15mm headed bolts.
Then torque 13mm main cap bolts to 80 degrees of rotation following a similar pattern as above.
Finally torque 15mm studded main cap bolts to 53 degrees of rotation.
My angle torque wrench logs the actual torque and it usually shows 58-62lb ft when I angle torque main cap bolts, but I would still use the above procedure.
Last edited by -Joseph-; May 4, 2009 at 08:01 PM.
Thread Starter
Staging Lane
Joined: Jun 2005
Posts: 77
Likes: 1
From: New Orleans
thanks for the help.
im not sure all of the main bolts come out for the tray, havent looked at it yet. If not, I should only need to retorque the ones I take out right?
Also, what do you use to keep forward pressure on the crank? I dont want to be prying on it with a pry bar.
Dont want to be a pain, Just want to get it right.
im not sure all of the main bolts come out for the tray, havent looked at it yet. If not, I should only need to retorque the ones I take out right?
Also, what do you use to keep forward pressure on the crank? I dont want to be prying on it with a pry bar.
Dont want to be a pain, Just want to get it right.
Joined: Nov 2001
Posts: 3,043
Likes: 0
From: Texas and Qatar
You shouldn't have to mess with the actual main cap bolts for just a windage tray swap if that's what your getting at. If so, you don't need to do any of the above info I posted. The windage tray nuts get torqued to 18lb ft. Nothing special install-wise, but remember to replace the oil pickup tube o-ring with a new piece as cheap insurance.
Hey Joe, quick question...I'm rebuilding an LS1...I got the crank in dry, with some plastigauge, do I use the same torque for the plastigauge as I would to torque for assembly? (I no plastigauge ain't exactly accurate but I see it better than nothing). the engine has 115k miles on the bolts and this is the first rebuild so if I torque em for plastigauge (2nd total torquing) can I use the bolts for final assembly? which would be the 3rd torquing. and can you explain a little more on the torquing while maintaining pressure on the crank? I've always just snugged it out down then pryed the crank forward and back to set the thrust bearing then torqued it..
Thanks!
Thanks!
Joined: Nov 2001
Posts: 3,043
Likes: 0
From: Texas and Qatar
Hey Joe, quick question...I'm rebuilding an LS1...I got the crank in dry, with some plastigauge, do I use the same torque for the plastigauge as I would to torque for assembly? (I no plastigauge ain't exactly accurate but I see it better than nothing). the engine has 115k miles on the bolts and this is the first rebuild so if I torque em for plastigauge (2nd total torquing) can I use the bolts for final assembly? which would be the 3rd torquing. and can you explain a little more on the torquing while maintaining pressure on the crank? I've always just snugged it out down then pryed the crank forward and back to set the thrust bearing then torqued it..
Thanks!
Thanks!
I don't think you will see a difference in plastigage (not accurate enough to tell the difference) by snugging the bolts down, vs. torquing the bolts to spec. But you are supposed to torque to specs when checking bearing clearances.
On thrust bearing alignment, I usually use a prybar on the snugged up #4 main cap against the crankshaft. It wouldn't hurt to use a soft-faced dead blow hammer to tap the crank forward, back, then forward again right before holding pressure on it.
If your building the 98 block, I would recommend replacing those main bolts. I've noticed when retorqueing the earlier bolts they 'feel' like they are stretching more than the newer LS main bolts and usually take less torque to achieve the "80" and "53" degree's if that makes sense. If you want some take-out bolts, I may have an extra set from a new block, I'll have to check out at my shop. Send me a PM to remind me.
I don't think you will see a difference in plastigage (not accurate enough to tell the difference) by snugging the bolts down, vs. torquing the bolts to spec. But you are supposed to torque to specs when checking bearing clearances.
On thrust bearing alignment, I usually use a prybar on the snugged up #4 main cap against the crankshaft. It wouldn't hurt to use a soft-faced dead blow hammer to tap the crank forward, back, then forward again right before holding pressure on it.
I don't think you will see a difference in plastigage (not accurate enough to tell the difference) by snugging the bolts down, vs. torquing the bolts to spec. But you are supposed to torque to specs when checking bearing clearances.
On thrust bearing alignment, I usually use a prybar on the snugged up #4 main cap against the crankshaft. It wouldn't hurt to use a soft-faced dead blow hammer to tap the crank forward, back, then forward again right before holding pressure on it.
So I snug all them up to the torque spec and then set the thrust bearing alignment, hold the forward pressure, and then torque all the rest to the angle degrees? or I just snug them handtight, adjust the thrust bearing hold the pressure then torque everything to the torque spec and angle degrees? Normally I torque the thrust bearing first, but it just confused me when you said pry on the already snugged up #4.
Thanks
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So I snug all them up to the torque spec and then set the thrust bearing alignment, hold the forward pressure, and then torque all the rest to the angle degrees? or I just snug them handtight, adjust the thrust bearing hold the pressure then torque everything to the torque spec and angle degrees? Normally I torque the thrust bearing first, but it just confused me when you said pry on the already snugged up #4.
Thanks
Thanks
snug them handtight or torque them to spec then adjust the thrust bearing?
I need to do this soon, thanks
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