401 Balancing And Replacement Flywheel.

I’ve attempted to search and I can find new build info on the external balancing of the cranks and flywheels on 401 motors. My question is, will there be any longevity to this motor if an off the shelf 401 flywheel is installed on the motor without a machine shop balance of it and the crank? Or will it hammer the bearings out of it in short order?

Or, am I just over thinking this, and as long as it’s balanced for 401 factory internals off the shelf will be ok?

 

I would not run it without balancing. With an external balanced engine you could end up a long way off of where it needs to be without ALL the correct components. Not like skipping the balance job for an internally balanced engine. That said, I get everything balanced. It's a relatively minor piece of the entire budget and very worth it.

 

An off the shelf flywheel should work without any problem, but it'll only bring it within factory production specifications. By balancing the rotating assembly, there will be less vibration. Ron

 

That’s what I needed to know, I have picked up a good running, good vacuum, good oil pressure hot with no blow by 401 that didn’t come with a flywheel and didn’t want to tear it down just yet just to balance the flywheel. But don’t want to hammer the bearings out of it or worse either.

I may just take it down and freshen it up anyway, if for anything, a better piece of mind to really know what I have and have it done right.

 

Just make sure it's for a 401. Ron