Theoretical question about "Quench"
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I've always during the assembly of the short block. Use a dial indicator on the on both the 12 o'clock and 6 o'clock. Place the piston at exactly TDC. Then use a hammer wood handle and press one side of the piston (piston rock)
Way to many variables. Like how tall is the piston, bore size, piston pin placement. Like motorhead's and my 427 4 inch stroker small blocks the piston pin is very close to the top behind the oil ring. Piston to wall clearance, and type of rings. How heavy is the piston.
So if you have over say .036 or .040 you are good to go. It's people trying to get down around .030 that have to start measuring everything.
Race Director
Joined: Jul 2004
Posts: 12,713
Likes: 329
From: Scottsdale Arizona
That isn't half bad. Presumably the rock would be less on a warm engine than on a cold one so this would be a worst case measure.
Thread Starter
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
One thing of note is that when GM built this stuff they used .020-.025 or so deck height and steel shim head gaskets that were only .018"-.021" or so. So that means total quench was only around .038" to .046". They weren't using .038"-.041" composition gaskets like most folks use during rebuilds.
Maybe The General DID know a little something??
JIM
Maybe The General DID know a little something??
JIM
I am happy to see others that aren't completely caught up in the "squish" factor and those who give honest answers based on there own experiences are the ones to listen to like Jim above, Manuel Azevedo and of course my small block buddy gkull and others.
There is much talent and experience in this thread from those who answered instead of quotes from hot rod books and other internet sources I was expecting to get
Melting Slicks
Joined: Jan 2004
Posts: 3,249
Likes: 210
From: Detroit MI
One thing of note is that when GM built this stuff they used .020-.025 or so deck height and steel shim head gaskets that were only .018"-.021" or so. So that means total quench was only around .038" to .046". They weren't using .038"-.041" composition gaskets like most folks use during rebuilds.
Maybe The General DID know a little something??
JIM
Maybe The General DID know a little something??
JIM
Race Director
Joined: Jan 2000
Posts: 13,025
Likes: 2,266
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
And yep....you can sure get a lot of variance on a stock block on decks! As mentioned...fast machining for sure!
But the fellow who rebuilds one with cheapo replacement pistons that put it .040"+ down in the hole and uses some .050" gaskets has a real pig!
JIM
