bryn.riley1
New User
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 10:50 am.
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 10:50 am.
Having the same problem with a 2640. New crank hit weights was told by after market parts vender to shave off what was needed. Did this and assembled. Put tractor on dyno half load 2500 rpm. In 10 minutes with 60 psi oil pressure white and blue smoke started to come out of breather tube. Pulled pan found spun balancer bushings. Bushings were new and installed by a reputable machine shop also had new shafts. Suppose at balancer shaft speed of 5000 rpm shaved weight through it out of balance ? People want me to pull shafts plug oil holes and run it. I think the crank is the culprit and weights need to be correct. Any ideas?[/img]