What pistons with 3.8" crank?
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,804
Likes: 1
From: OKC Oklahoma
What pistons with 3.8" crank?
I am looking to do something with this 400 block I have and have considered purchasing a 3.8" stroker crank. Does this require special pistons or what?
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by 79VetteMike
I am looking to do something with this 400 block I have and have considered purchasing a 3.8" stroker crank. Does this require special pistons or what?
RACE ON!!!
Drifting
Joined: Dec 1999
Posts: 1,462
Likes: 1
From: Reno nevada
Look at the JE or wiseco sight and they might have them in their online catolog. George told me that his Wiseco pistons actually are -20 or 22 cc dished to keep compression down. Your going to end up with something under 415 ci without an overbore and you need to look at 15 or so cc dished to keep your compression down
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by Lt1er
Look at the JE or wiseco sight and they might have them in their online catolog. George told me that his Wiseco pistons actually are -20 or 22 cc dished to keep compression down. Your going to end up with something under 415 ci without an overbore and you need to look at 15 or so cc dished to keep your compression down
How can you speculate on the piston configuration he may need, since he hasn't mentioned what heads he wants to use. Most piston manufacturers offer a variety of configurations. More that one dome size and more than one dish size.
With a typical, .030" overbore, the 3.80" stroke yields 412 CID. Less with a standard bore.
RACE ON!!!
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,804
Likes: 1
From: OKC Oklahoma
I have Pro Topline aluminum 200cc/64cc heads. The crank I was looking at getting is a Cola superlight crank on Ebay. A guy from another board says that his buddy is also selling a Cola, because it would take too much mallory to balance it, but from the pictures, it didn't look like a superlight. I don't want to go this route if pistons are going to cost me $600+.
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Originally Posted by CFI-EFI
NO! With a stroke .050" longer than the 3.75" 400 crank, the piston rises (and drops) .025" higher (and lower) in the bore. It is an ideal way to get a reduce the deck clearance to obtain a good quench area with minimal decking of the block. The advantage in the quench will be greater than the approx 6 cubic inches you'll pick up, and for less cost (I assume) than the greater amount of block decking. Good move.
RACE ON!!!
RACE ON!!!
Stroke is the offset from the main journal center line to the rod journal center line. An aditional .050 stroke would lift the piston .050 more in each direction. Which with the typical .025 piston to deck Your above the deck .025. That's not a problem. I have a friend with a race boat that uses .060 copper head gasket with an O-ringed block and that's how he got his quench height correct
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,271
Originally Posted by gkull
I beg to differ on this statement. I need correction mysef at times :o
Stroke is the offset from the main journal center line to the rod journal center line.
Stroke is the offset from the main journal center line to the rod journal center line.
Most pistons also have enough crown thickness that shaving the tops up to .025" to get your target CR or quench clearance will not reduce strength or reliability.
Duke
Last edited by SWCDuke; Feb 6, 2005 at 10:46 PM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by SWCDuke
No, that's the "crank throw radius", which is half the stroke. A stroke increase of .050" means a .025" increase in crank throw radius, which will raise the piston crown .025".
Duke
Duke
Thank you Duke, you saved me the trouble.
gkull,
See post #3.
RACE ON!!!
