C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

L98 Head Bolts & Washers?

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Old 01-11-2005, 03:01 PM
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geezel
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Default L98 Head Bolts & Washers?

The stock head bolts on my 86 alum. heads have washers. The new set of Manley head bolts are shoulder bolts with no washers. Should I add washers or not? No washers = affect on torque readings?
Old 01-11-2005, 03:55 PM
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pablocruise
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Defintely use washers so as not to gall the Al head with the bolts as they get torqued down.

btw, for anyone reading, don't re-use factory head bolts as they are torque to yield. They've stretched.
ARP

Last edited by pablocruise; 01-11-2005 at 04:00 PM. Reason: spelling
Old 01-11-2005, 03:57 PM
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geezel
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Galling the heads is not an issue as the Manley's are shoulder bolts.
Old 01-11-2005, 04:26 PM
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CFI-EFI
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Originally Posted by 89 Paul in Cal
btw, for anyone reading, don't re-use factory head bolts as they are torque to yield. They've stretched.
ARP
On an '86???

RACE ON!!!
Old 01-11-2005, 04:49 PM
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geezel
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Late 86 with aluminum heads. I'm actually installing a new set of AFR/TPIS heads now.
Old 01-11-2005, 05:30 PM
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cv67
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Originally Posted by geezel
Late 86 with aluminum heads. I'm actually installing a new set of AFR/TPIS heads now.
Old 01-11-2005, 07:07 PM
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Davemc1963-87conv
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Originally Posted by CFI-EFI
On an '86???

RACE ON!!!
I think CFI-EFI means that on an 86 the bolts if original would not have been torque to yield fasteners and can be reused.
However, on Aluminum heads as far as I am concerned, you need to use washers on the bolts to prevent the harder steel bolt galling (cutting into for want of a better description) the softer aluminum head when tightening/torquing down.
Check the application list for your new bolts, if they dont have washers, they may be meant for cast iron heads only.
Old 01-11-2005, 07:22 PM
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geezel
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"Shoulder" bolt is the wrong term. They have a flange that is formed as part of the hex head which may act as the washer.
Old 01-11-2005, 07:56 PM
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85vet
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Originally Posted by geezel
"Shoulder" bolt is the wrong term. They have a flange that is formed as part of the hex head which may act as the washer.
ARP's are similar to what you describe. The washers are beveled to fit properly.
Old 01-11-2005, 08:04 PM
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CFI-EFI
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Originally Posted by Davemc1963-87conv
I think CFI-EFI means that on an 86 the bolts if original would not have been torque to yield fasteners and can be reused.
That's EXACTLY what I meant. Was I unclear, AGAIN???

Even with a flange headed bolt, I would use a washer if the bolts are long enough.

RACE ON!!!
Old 01-12-2005, 10:11 AM
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Midnight 85
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I have built my own engines since I was 17 years old but had never came across "torque to yield" head bolts before my 85 L98. I knew the small block torque spec and sequence by heart so I just went ahead and started tightening the head bolts down. As luck would have it I snapped off the last one to be tightened. I was highly miffed so I went and bought a whole new set, this is when I learned about "torque to yield". Sure wish I had new it a couple hours earlier. Anyway, do NOT re-use any headbolts and I agree with CFI-EFI, use washers if length permits. The shoulder of the bolt is still going to gall the aluminum.
Old 01-12-2005, 10:12 AM
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geezel
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Washers it is. Thanks all.
Old 01-12-2005, 12:27 PM
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VetNutJim
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Where to get HARDENED WASHERS guys?
Don't use standard soft ones.
Old 01-12-2005, 02:41 PM
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Originally Posted by VetNutJim
Where to get HARDENED WASHERS guys?
Don't use standard soft ones.
GM part number, 10051155, for one.

RACE ON!!!
Old 01-12-2005, 02:42 PM
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Originally Posted by VetNutJim
Where to get HARDENED WASHERS guys?
Don't use standard soft ones.
Summit, Jegs, local race shop should all have hardened washers.

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