Not A Motor Head??

OK... I'm dumb, what's a stroker??

I know the term stroked and bored, boring out cylinders to oversize for more volume, I know and understand. In quick terms, whats stroking and is the benefit more torque, power??

Without doing searches and picking through forums, can anyone edumacate me as to how it helps us in wheelin??

Try a search for stroker. Lots of good information like this: http://www.naxja.org/forum/showthread.php?t=46309&highlight=stroker

Dr. Dyno has a link under his signature.

To "stroke" a motor is to replace the crankshaft with one having a longer "stroker" - or crankpin throw. In our case, the typical "stroker" has the 242 crank removed (stroke 3.413") and replaced with the 258 crank (stroke - 3.895") and the shorter 258 rods installed. The shorter rods are vital - they keep the pistons from "self-clearancing" on the cylinder head.

Just pulling the crank and going to the 258 will give you something like 40-45 extra cubic inches and a slightly increased compression ratio, with a nice little boost in low-end torque. Greater increases can be had by adding a "boring" operation to the block (taking it from 3.875" to 3.905", 3.935" or even 4.000") with the resulting increase in displacement. Also, Jake's Racing Engines offers crankshafts with strokes of 3.98" and 4.06", so you can really kick this up (but the longer stroke crankshafts typically require custom connecting rods and/or pistons to keep the pistons from hitting the cylinder head.)

This was an interesting chapter to write for my book, and I'm working on some more information for it (I had to get the first done before I went back to school - but there's so much more to cover.)

Check with Dr. Dyno/Dino Savva, and quite a lot of information can be had by visiting groups.yahoo.com/group/strokers and searching about.

5-90

The size of a motor, Cubic Inch Displacement is determined by the cylinder bore cross section area X piston stroke X number of cylinders. It's pretty difficult to increase the number of cylinders, but you can increase the bore or stroke to add diisplacement. More displacement will draw in more air and fuel which will result in more power. To increase the stroke, the length of the crankshaft throw is increased. Besides increasing the displacement of the motor, a longer stroke increases the length of the lever arm that the piston and rod push down on to turn the crankshaft. A longer stroke increases the leverage applied to the crank for a given displacement so torque is increased in this way as well.

OK makes sense now. Crank arms and shaft get changed in a stroker I see. How about the length of the piston itself? Is it shortened at all. Seems like the gains wouldn't be all that noticable compared to all the work involved... This sounds like a "geek tweak" as us in the IT world would call it.

Using -85's numbers, (242 stroke 3.413" vs 258stroke 3.895") results in a 16% increase in displacement and a 16% increase in the pistons lever arm. That is a pretty hefty increase in torque. Sometimes the distance from the wrist pin center line to the top of the piston is modified, but this doesn't change displacement.