Definition help: Stroker

[Grover]

I've seen the term stroker/stroked motor used but honestly don't know what it is. Can someone enlighten me? And please, at least one person needs to post the REAL answer before others chime in with smart-ass responses.

[andrewro]

A motor with a longer stroke than stock - a "bigger" crankshaft will give you the longer stroke.

[BillWilliams]

that is larger in displacement. I believe displacement is measured by the diameter of the piston and the length of the stroke.

The engine builders can provide the actual calculation

[aaronr]

and we all know---- "there's no replacment for displacment"--- oh wait we don't know that do we

[KFunk]

The real common one is a 383 ci stroker.

Its just a 350 cubic inch engine block like you find in so many chevys, with a 383 stroker kit. With the longer stroke of the pistons, the total displacement of the engine is bigger, thus you get a 383 cubic inch engine starting with a 350 block.

There's another variaton that 02ers have heard about: de-stroking. To get a lot of power out of the M10 four cylinder engine, the F1 team needed to make it rev higher. But to make it rev really high quickly, you don't want a huge stroke of the piston up and down, you just want some rapid up and down movements. So, they shortened the stroke of the piston, making the total displacement only 1.5L. But, with lots of turbo and high revving, they got like 1500 hp out of the lil buggah.

[Napes]

I believe the generally excepted estimate on the early 80s F1 engines were 1350HP in qualifying trim, 1150HP in race trim. Not too shabby for a 91 cu.in. four-banger.

Bob Napier

[ingraham]

Thanks, andrewro.

Stroke is the distance traveled by the piston between top and bottom. You increase the stroke by changing the crankshaft to one whose rod journals are farther from the centerline of the crank. When doing that, other changes are often needed, such as different pistons.

Displacement is stroke times the area of the bore. The other way to increase displacement is to increase bore, i.e. with a larger cylinder and piston diameter.