Crankshaft help

[Dutmac]

I have a L3000DT that has a D1503 engine in it. My oil pump locked up and spun my bearings. I am planning on ordering a new crankshaft, but when I called they told me that there were two options on crankshaft. One of them costs $1800 the other costs $2400. My question is, what is the difference?

I have spotted a used crank online but this discrepancy in crankshafts has me puzzled. Can anyone clear this up for me?

 

[1970cs]

Engine serial number break!

Pat

 

[Kubota Newbie]

Design change based on SN of engine/tractor.

If you spun the bearings the main bores in the block and or rod big ends will likely need to be resized as well.
Have you had a good crank shop look at the original crank to be sure that it can't just be ground undersize??

 

[Dutmac]

It did indeed spin my main bearing. We purchased a new bearing and it pushes into the block very easily.

You can see on my crank the colors of the temper where my pistons attach to the crank also. I really think I should get a new crank, but I don’t know if it is the proper crank for the block because of the change.

If I had more info on crank and block specs as far as sizes and tolerances, I would be more adventurous. But it seems that isn’t info that is readily available.

I am leaning more toward just buying a completely rebuilt motor. It’s gonna hurt though.

 

[D2Cat]

I'm pretty sure Kubota has rod bearings that are .2mm and .4mm for undersized cranks. Be worth checking for your particular crank, so you don't have to purchase something you're not sure of.

 

[North Idaho Wolfman]

Most likely the change in the Crank was very minor, like a direction of the oil galleys.
The reason I say this is if it was a major change there would be a bunch of other parts that would have to change as well.
It's calling for the same bearings so there was no change in the size of any of those specs.

 

[Dutmac]

I do appreciate you guys help with this, the guy helping me with my tractor just called and said that he can push the front main bearing into the block with his fingers. I am going to need a new block. Did you know that there aren’t any D1503 motors out there? At least that I’ve been able to find?

So I called the dealer to see what a new motor would run me.....$4900 plus tax. At what point do I bite the bullet and go buy another tractor?

Do you gentlemen have any of these motors squirreled away for a rainy day? Cause I am in the market for one.

 

[coachgeo]

Can a machinist weld in some new metal on the block and then re- bore the hole for the crank bearing to proper size?

 

[D2Cat]

If you are considering going with a different tractor, you might contact these folks and see if they have an interest in yours. Might help you to see how much you want to spend to get this one going. Maybe they have an engine?

http://www.japanesecompacttractor.com/default.htm

 

[Kubota Newbie]

So if it were mine I'd just fix that one. But I'm pretty handy.
I wouldn't be afraid to put a steel spacer sleeve in the front main and live with it. (but I also have access to a shop where I could do it myself).
Should first see if Kubota offers an "oversize" front bearing shell that would allow re-honing the bearing bore to a larger size?
If not, I'd go to an automotive machine shop that does block and crank work maybe even NAPA and see if they could spec a bearing shell from their book that had a bore diameter slightly larger than std but matched the correct inside diameter. That would also allow re-sizing the block hole.
I'm assuming that the bearing bores in the rest of the bearing carriers measure within spec.?

BTW... No, you can't "weld" on it and then re-machine it. The block is iron, the welding process will create hard spots no matter how you do it and you'll never be able to re-machine and hone a true bearing bore (remember we're talking tenths of thousandths to get within spec)

 

[Luckystars]

Go a little further with this block before you make up your mind what direction to go. If you went long enough to scald and spin rods and mains, what about wrist pins and cam bushings and lobes? Did any shrapnel spread through out the engine?
Would any other used engine size fit the tractor frame?

 

[JohnDB]

Do you know what caused the oil pump to lock up? Could it happen again?