John Deere 2640 crankshaft issue

I'm working on rebuilding/restoring a 1982 John Deere 2640 (with a 4.276 motor in it) that spun a main bearing. I had the block and crankshaft gone over by a local machine shop. The crankshaft is toast, they ordered a replacement and went over it putting the dowel and crank gear on the new crank.

After reassembling and timing the block, crankshaft, pistons and balancer shafts I spun the crankshaft around and the balancer shaft weights are hitting the new crankshaft behind the first piston. The rear weights are fine.


When I spoke the the machine shop again they said they talked with their supplier about the new crankshaft. Their supplier said that John Deere changed the casting to fit more engine series and that the fix was to shave some of the balancer shaft weight to make everything clear. To do that I'd have to shave about 1/8" to 1/4" of the weight off on both sides of the crankshaft. It just isn't sitting right with me to shave that much off the weight.

I spoke to my John Deere parts guys and they couldn't see anything in their system to verify the different crankshaft or balancer shaft weights.

Does anyone know if any of the machine shop suggested seems correct?

This post was edited by bryn.riley1 on 03/06/2023 at 10:53 am.

I'm GUESSING that this is an aftermarket crankshaft vs. a used or reconditioned OEM crank?

yes its an aftermarket part. I believe it is a Reliance.

This post was edited by bryn.riley1 on 03/05/2023 at 05:36 pm.

Problem is once you take metal off
the balancer shaft weights your
going to lose the balance. Never
heard of anyone recommending doing
that.

(quoted from post at 18:44:05 03/05/23) Problem is once you take metal off
the balancer shaft weights your
going to lose the balance. Never
heard of anyone recommending doing
that.

Click to expand...

That's one of my major concerns as well, they're there for a reason so don't mess with them.

I try here first ,Ive used them ,they do excellent work . Told my friend ,he got his work done there ,same results .

To contact Harts Machine Service for service call 419-399-4777 or

email us at [email protected]

Our address is:

Hart's Machine Service,

106 North Main Street,

PoBox 13,

Cecil, Ohio, 45821

I post this before there are others here that say the same

Not too sure about re-installing used gears .

I imagine you would have tried to find a good used crank first, so that's clearly not an option. You're stuck with what you have.

As I see it you have two choices here:

1. Go with the machine shop's recommendation.
2. Leave it alone and have a non-running engine.