Stroker Motor Silly Question
Thread Starter
Pro
Joined: Oct 2004
Posts: 628
Likes: 6
Stroker Motor Silly Question
For the life of me I cant work out how a motor can be signifantly stroked without the pistons contacting the valves. Probably a really silly question, but what bits get changed when a motor is stroked?
Thanks!
Thanks!
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Crank is also different.
Safety Car
Joined: Mar 2005
Posts: 4,465
Likes: 1,223
From: Fredonia WI
2025 Corvette of the Year Finalist - Unmodified
2024 C7 of the Year Winner - Unmodified
2023 C4 of the Year Finalist- Modified
2020 C4 of the Year Finalist - Modified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
94z07fx3 , wow - nice animation! 
Gary
Gary
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: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by 89 Paul in Cal
...and the rods can be longer.
RACE ON!!!
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
If you plan to use the stock pistons, the rods had better be shorter. How many people know that you can build a 383 with stock 350 pistons if you use the 400 rods? Conversely, you can build a 377 (4.155 bore X 3.48" stroke) using stock 400 pistons on the 350 rods.
RACE ON!!!
RACE ON!!!
-- Joe
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
That combination won't rev any higher than with a 5.7" rod. Granted, the rod angle is better.
The point was about what HAD to be changed. You could use 6.00" rods, 6.125" rods, or...??? If you are willing to change everything, the combinations are almost infinite.
RACE ON!!!
The point was about what HAD to be changed. You could use 6.00" rods, 6.125" rods, or...??? If you are willing to change everything, the combinations are almost infinite.
RACE ON!!!
When you think about it, a 383 is horrible for loading the cyl walls. Which is why most 383 cyls end up egged shape after time.
A 6" rod will do the same thing as a 5.850" rod on a 3.48 stroke, but the more you move the wrist pin up on the piston the less crown you have to take the heat.
But yes, this is off topic.
-- Joe
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by anesthes
You can also use 5.850" rods, stroker pistons, and a 3.48 stroke crank which improves rod angle, and revs high.
-- Joe
-- Joe
The point was about what HAD to be changed. I merely gave two examples of the reutilization of more parts than most. You could use 6.00" rods, 6.125" rods, or...??? If you are willing to change everything, the combinations are almost infinite.
RACE ON!!!
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by anesthes
A 3.48 stroke with a 5.850" rod will rev "better" than a 5.7 rod 350,
Originally Posted by anesthes
When you think about it, a 383 is horrible for loading the cyl walls. Which is why most 383 cyls end up egged shape after time.
Originally Posted by anesthes
A 6" rod will do the same thing as a 5.850" rod on a 3.48 stroke,
Originally Posted by anesthes
But yes, this is off topic.
-- Joe
-- Joe
RACE ON!!!
Race Director
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
I used 6" rods and 1.25" compression height pistons. The chosen pieces were stronger and lighter than the stock rods/pistons. To balance the assembly the machinist had to remove weight from the crank.
The lighter assembly should rev quicker and hold together at higher revs than a heavier assembly. So another benefit of longer rods is shorter/lighter pistons, however, a shorter piston has its drawbacks too. So choose wisely, and match all of your components to the desired usage. IE don't install a 3.875 stroke cast crank if you want a 10,000 rpm screamer and the inverse is just as bad don't build a 3" bore 1.5" stroke engine with a 245* cam and expect stump pulling torque at 800 rpm.
MIke
The lighter assembly should rev quicker and hold together at higher revs than a heavier assembly. So another benefit of longer rods is shorter/lighter pistons, however, a shorter piston has its drawbacks too. So choose wisely, and match all of your components to the desired usage. IE don't install a 3.875 stroke cast crank if you want a 10,000 rpm screamer and the inverse is just as bad don't build a 3" bore 1.5" stroke engine with a 245* cam and expect stump pulling torque at 800 rpm.
MIke
Safety Car
Joined: May 2006
Posts: 4,290
Likes: 140
From: Salem NH
Call a few engine builders, ask around. I'm not here to argue.
-- Joe
[/QUOTE]
