D722 crank bearings - size?

[Delmar]

I'm helping a friend with a project and we're stumped. Rebuilding a Kubota D722 engine and bought a crankshaft that had been "ground." Took it to a machine shop and they confirmed it had been ground, and standard bearings are loose on the crank. The bearings that were with the crank don't have any markings that indicate size. Hoping some smarter folks than me might have some advice. Kubota dealer only sells standard bearings.

1. Is there a standard size a crankshaft would have been ground? Is it like ordering piston rings for a bored-out cylinder?

2. Does anybody know a good source for crank bearings for a crankshaft that's been ground?

Thanks for any advice.

 

[lugbolt]

Yes-typically (on automotive stuff) they make crank and rod bearings that are .001, .002, .010, .020, .030, etc UNDER-sized. "Undersized" because the crankshaft is ground to a smaller diameter to clean up the damage, thus the bearing shells need to be smaller to properly fit the now smaller diameter journals.

Kubota used to offer them in undersizes. I found them while looking for bearings for a G1900 as I recall, which is in fact a version of the D722. They call them "crank metals" and "rod metals". Crazy descriptions but that's what they are-metal bearings.

 

[Delmar]

Thanks, lugbolt. We'll take another run at the dealer.

 

[D2Cat]

I remember on a V1902 engine Kubota had .2mm and .4mm undersized rod bearings. Only choices.

 

[200mph]

As D2Cat mentioned, they look to be +0.20 mm and +0.40 mm from this source.

http://www.waltstractors.com/acatalog/KU14218---V1902-Kubota-Engine-Main-Bearing---Individual-Oversize---.20-MM-92871.html#SID=13629

http://www.waltstractors.com/acatalog/KU14219---V1902-Kubota-Engine-Main-Bearing---Individual-Oversize---.40-MM-92872.html#SID=13629

I hope whoever ground the crank knew what bearings were available before they did so.

Good luck.

 

[North Idaho Wolfman]

You never said if it was a main or a rod jornal that was ground?

 

[zuric]

Get your hands on some Plastiguage, doesn't cost much. Tells you what your final clearance will be.
A micrometer will tell you the journal size instantly..surprised the 'machine shop' didn't pass that info on to you.

 

[Delmar]

Thanks, NIW and zuric. I'm not sure if it was the main rod or journal that was ground. I'll have to do some more investigation. Zuric, plastigauge and micrometer might be the route to go if we don't figure it out before. I appreciate the suggestion.