Heads on Ls2
04-17-2007, 02:31 PM
#4
Safety Car
Requires new head bolts. Need a Torque Angle guage.
Service Manual describes -
For the 10 M11 bolts inside the valve cover:
Starting in the center working your way out, first pass to 22 lb ft.
Second Pass to 90 degress.
Third Pass to 70 degress.
Then tighten the 5 M8 bolts outside the valve cover:
Starting in the center, just one pass to 22 lb ft.
Service Manual describes -
For the 10 M11 bolts inside the valve cover:
Starting in the center working your way out, first pass to 22 lb ft.
Second Pass to 90 degress.
Third Pass to 70 degress.
Then tighten the 5 M8 bolts outside the valve cover:
Starting in the center, just one pass to 22 lb ft.
04-18-2007, 12:01 PM
#6
Safety Car
Member Since: Jun 1999
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I installed new stock GM Torque to Yield head bolts once. Although cheap, they were not worth the cost/effort to mess with a torque angle meter. If you over torque them, the stretch too far, they loose their clamping force and you have to replace it.
My recommendation is to go with basic ARP all the way.
My recommendation is to go with basic ARP all the way.
04-19-2007, 11:23 PM
#7
Tech Contributor
Just the 411 on the stock bolts. If you go in for warranty work and a head comes off under warranty, the manual says to re-use the same bolts. If you go in after the waaranty period, they use new ones.
source: Brad at ramp chevy in port jeff NY
source: Brad at ramp chevy in port jeff NY
04-20-2007, 12:57 AM
#8
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Important:
• Do not use the cylinder head bolts again. Install NEW cylinder head bolts during assembly.
• Do not use any type of sealant on the cylinder head gasket, unless specified.
• The cylinder head gaskets must be installed in the proper direction and position.
From the 2007 manual:
Important: The cylinder head bolts are NOT reusable.
Did Brad actually say that the procedure was to reuse the bolts if the car was under warranty?
04-20-2007, 09:53 PM
#9
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I researched the TTY (Torque to Yield) head bolts when I was having my LT-4 heads ported.
The conclusion was DO NOT reuse TTY bolts because during the installation, they "stretch" to achieve the correct clamping force. If they are reused, when you turn the bolts per the angle spec, there is no way to tell if the clamping force is correct. Think about a rubber band. The first time you stretch it, it has a high resistance. The next time, less.
Although I was unable to confirmed in my research, my theory is the thermal expansion/contraction of the aluminum heads are served better with TTY bolts that can stretch/contract a few thousands to maintain consistent clamping force to the block. Of course, head gaskets material also have a lot to do with maintaining a good seal.
The conclusion was DO NOT reuse TTY bolts because during the installation, they "stretch" to achieve the correct clamping force. If they are reused, when you turn the bolts per the angle spec, there is no way to tell if the clamping force is correct. Think about a rubber band. The first time you stretch it, it has a high resistance. The next time, less.
Although I was unable to confirmed in my research, my theory is the thermal expansion/contraction of the aluminum heads are served better with TTY bolts that can stretch/contract a few thousands to maintain consistent clamping force to the block. Of course, head gaskets material also have a lot to do with maintaining a good seal.
