Reply to "Stroker engine vibration"

Kristian you have my sympathy, I'm sure you're feeling pretty bad already.

The thread didn't get off track when Marlin made his comments; its getting off track when members start judging the post of another member. Lets all stay on topic, which is Kristian's Pantera motor. The topic is not our personal opinions of Marlin. That's not what some of you wanted to read is it? I may end up editing some of the comments about Marlin ... and Marlin's replies to those comments. Nobody get all bent out of shape, OK?

There are a few lessons here in regards to Kristian's motor ... here's my two cents.

The manufacturers of inexpensive crate motors are not going to use mallory metal to balance a reciprocating assembly via the crankshaft, mallory metal is very expensive, the crate motor manufacturers want to keep the retail price of the crate motors as low as possible, but they also want to make a nice profit. So they balance their motors as inexpensively as possible ... possibly using the flywheel and damper. If there are signs of that having been done, those parts need to stay with that motor.

The billet steel flywheel was the better part anyway. Its tough, durable, safe. It will last a long time without giving the owner any trouble. Aluminum has a bad tendency to work harden and crack. Aluminum is not a good material to use on reciprocating assembly parts, except in situations where the motor isn't expected to last a long time anyway.

The lure of an aluminum flywheel is to make the motor rev a little faster. But stop and think for a moment. A 500 foot pound stroker motor installed in a vehicle equipped with street tires doesn't need to rev any faster, its just going to be that much easier to break the rear tires loose, its going to make traction harder to control. A seven liter V8 with a 4" stroke crankshaft is a tire frying beast. The extra weight of the steel flywheel is actually a good thing for such a powerful motor used in a street application. The limit to the car's acceleration is going to be traction, not the weight of the reciprocating assembly.

-G