Forged Pistons
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by lefoy84
I read in a performance book that 84 and up came with forged pistons. Anyone know if this is true? I have the L98 out my 86 and am shopping for pistons. I was leaning toward hypereutectic.
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From: eville in
Originally Posted by Corvette Kid NC
Hypers are fine for most street engines as long as you're not going to force feed or bottle feed it.
read a lot of people use a low level boost and up to 125HPnos shot
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From: The Top of Utah
The 1984 and 1985 engines had forged pistons. The 1986 iron headed engine used a different part number piston. I don't know if those are cast, cast hyper, or forged. The '86 iron heads were the same as the '84-'85, therefore it was either a compression ratio change, a change in materials, or both.
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Originally Posted by vader86
85 is the only L98 with forged pistons.
They were leftovers from the late C3s.
They were leftovers from the late C3s.
I am leaning towards Keith Blacks.
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From: Athens AL
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The 86 piston is cast.
I keep hearing from builders that KB's are junk, take that however you want. I would probably go with forged, hyper is a little tougher than cast but not a great improvement.
I keep hearing from builders that KB's are junk, take that however you want. I would probably go with forged, hyper is a little tougher than cast but not a great improvement.
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Originally Posted by vader86
The 86 piston is cast.
I keep hearing from builders that KB's are junk, take that however you want. I would probably go with forged, hyper is a little tougher than cast but not a great improvement.
I keep hearing from builders that KB's are junk, take that however you want. I would probably go with forged, hyper is a little tougher than cast but not a great improvement.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by lefoy84
The thing I like about hypers is that they can be set with .002 clearance.
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Originally Posted by Corvette Kid NC
What are your overall goals for the engine, HP and intended usage? My machinist, a respected shop who does a lot of work for local racers here in Nascar country, admitted than when he first used hypers, he set them up like any other piston and had failures. He then contacted KB and found out where he went wrong and since then has had no problems and recommends them in suitable applications. The critical thing on them is top ring gap and if not set wide enough, it will destroy the piston in short order.
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by lefoy84
My eventual goal is a 325 HP street engine that I can stand on occasionally. No racing.
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From: The Colony Tx
For a long time in the 60's GM used forged TRW's in their HP engines. The only 'problem' I had with any of mine was a very occcational piston slap at startup. As soon as the engine warmed up, the noise went away. This was fairly common with forged pistons. I remember the first time it happened, it scared the crap out of me.
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Originally Posted by CFI-EFI
The 1984 and 1985 engines had forged pistons. The 1986 iron headed engine used a different part number piston. I don't know if those are cast, cast hyper, or forged. The '86 iron heads were the same as the '84-'85, therefore it was either a compression ratio change, a change in materials, or both.
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From: The Top of Utah
Originally Posted by MidLCrs
As a new member and a new Vette owner, I am interested in finding out what I have in my "new" '84. What heads do I have and what cc are they? The car is stock at present. Thanks.
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We have used the Kieth Blacks in a few motors since 1997. The clearances have varied between .0015 and .003. At .002 and greater they make a ton of noise that doesn't go away when warm. In January they sound like a diesel! I haven't been able to break them yet but the noise makes me nuts. Just thought I would share this info. I would use them again but not in a street car ( especially a vette).
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From: Good health is merely the slowest possible rate at which one can die
St. Jude Donor '04-'05-'06-'07
Originally Posted by Pete K
We have used the Kieth Blacks in a few motors since 1997. The clearances have varied between .0015 and .003. At .002 and greater they make a ton of noise that doesn't go away when warm. In January they sound like a diesel! I haven't been able to break them yet but the noise makes me nuts. Just thought I would share this info. I would use them again but not in a street car ( especially a vette).
