Rebuilding engine in '95 Bobcat 331

[zwelch]

I am trying to decide whether it will be worth the effort required to rebuild the Kubota v1902 engine in my '95 Bobcat 331. This would be a much bigger undertaking than I have ever attempted on my own. Rebuild kits seem to be readily available, but that path assumes that you know what you are doing. I have never rebuilt an engine, and I suspect this would be a poor choice of projects to learn as I go.

I have not been able to find a mobile mechanic that I would trust to do the entire job for me, and shop quotes have been more than I paid for the machine. I am waiting to get a quote from the local engine rebuild service, as I suspect that still will be more than I want to spend (and would require me to extract the engine and transport it to them).

I need this machine working before the end of the summer, or I will need to find a replacement. What are my best options?

 

[m7040]

Also doing it yourself if you don't have the tools lifts etc you will have to buy that. And there is a learning curve for this that you don't seem to have enough time for. So your options are limited to shop it and see what deal you can find.

 

[rScotty]

If the rest of the mini ex is good, my own first move would be to check out a factory replacement engine.

https://www.kubotaengine.com/engines/

I've done a number of rebuilds. Not all of them were successful, but they all cost more than expected. For that matter, there is a lot of latitude in in the term: "rebuild".

For a complete rebuild I'd be surprised if it didn't cost as much as a factory replacement engine.
rScotty

 

[zwelch]

Also doing it yourself if you don't have the tools lifts etc you will have to buy that. And there is a learning curve for this that you don't seem to have enough time for. So your options are limited to shop it and see what deal you can find.

I have a tractor that could lift the engine. I have tools for maintaining my machines. The learning curve seems to be the biggest obstacle.

 

[zwelch]

If the rest of the mini ex is good, my own first move would be to check out a factory replacement engine.

https://www.kubotaengine.com/engines/

Thanks for this reference. I looked around the site and couldn’t find a v1902…. Is there a newer model that would drop into place?

I think the rest of my my excavator is in good shape, but it’s definitely a tough call to evaluate the trade offs here.

 

[CliffordK]

What is the problem with the engine?

It looks like the rebuild kits are pretty complete with bearings, gaskets, cylinder liners, pistons, rings, etc.
Injectors, injection pumps, hoses, belts, etc, would be separate.

I doubt this is a mobile mechanic job, unless the mechanic can snag the engine, take it home, and bring it back ready to go.

You likely need to get into the engine to verify the condition of the cam, crankshaft, etc, before buying parts.

Before taking on the job, try to evaluate the benefit of success vs cost of failure.

For $500, it might be worth trying the rebuild, but if you get in too deep, replacement engines may be several thousand.

 

[laurencen]

over the years I have rebuilt many Kubota and Isuzu engines, some were complete rebuild others were new liners and pistons, grind valves in and gaskets, the factory service manuals are very good and give step by step plus what to check, what is wrong with the motor?

 

[zwelch]

I have not dug into the machine to determine exactly what's going on, but bearings started squealing and the engine now overheats fairly quickly. It got warm enough to kill the fuel pump, which probably saved it from worse damage. Given the symptoms, I suppose that it could "just" be the water pump that failed, but I suspect the heat did a lot more damage.

I have the service manual for the machine, and the procedures required for a complete tear down and rebuild looks doable. However, step 1 pretty much comes down to removing the cab and everything in it, so it's not a small undertaking and will require a big commitment (of both my shop space and free time).

At this point, I am shopping around for a new machine, so I can repair/rebuild this machine at my leisure with worrying about the outcome. I keep kicking around the idea of organizing a "rebuild club" of like-minded folks that want to learn the process hands-on. I'm guessing there are folks that would want to spend a couple of weekends a month working on that project over the course of a summer. With enough interest, might even find an instructor to come guide us through the process in person. That's gotta be worth something.... I mean, where else can you get this kind of hands-on experience?

If the rebuild looks too expensive or goes sideways, I can always part it out, particularly if it's already mostly disassembled. That said, I'm still considering my options.

 

[CliffordK]

As always, do the easy stuff first. Belts, Radiator, Water Pump, etc.
Do you have oil pressure?

If the bearings are squealing, you are in bad shape and could lose a crank or cam.

I've never done an oil test. But, that is apparently the new thing, and may well tell you the condition of engine internals.

It turns out you are pretty close.

I'm planning on building a new home shop this summer, but it will take some work getting equipment running.

I think I've found a new engine for my Bobcat 610 Skidsteer (4cyl Wisconsin). Partly disassembled by previous owner, and rusted cylinders. So, the new engine, then we'll see.

Then it looks like I'll be rebuilding a Continental F226 engine this spring for my Oliver Dozer.

 

[ROUSTABOUT]

I am trying to decide whether it will be worth the effort required to rebuild the Kubota v1902 engine in my '95 Bobcat 331. This would be a much bigger undertaking than I have ever attempted on my own. Rebuild kits seem to be readily available, but that path assumes that you know what you are doing. I have never rebuilt an engine, and I suspect this would be a poor choice of projects to learn as I go.

I have not been able to find a mobile mechanic that I would trust to do the entire job for me, and shop quotes have been more than I paid for the machine. I am waiting to get a quote from the local engine rebuild service, as I suspect that still will be more than I want to spend (and would require me to extract the engine and transport it to them).

I need this machine working before the end of the summer, or I will need to find a replacement. What are my best options?

Does it need rebuilding? I have only rebuilt kubotas when the head cracks. But if it ain't cracked, I keep going. Be careful taking injector lines off. Only turn the nut on the line. Don't turn nut below the line nut on injector pump. That is how a Kubota is timed. Open up problems turning one of those. And the main bearings are in a boss. Like an English standard diesel. You could just put rod bearings, rings, valves ground or lap yourself, umbrella cup stem seals, new head gasket. Rings for an American V8 is 65 bucks. Kubota rings are more than 65 bucks each cylinder. There are salvage yard engines out there too. Not too hard to change engine. Slides out like a drawer. Does it sit crossways to mach8ne with belt drive on drivers side? Some are long ways. I've seen them with Isuzu and Perkins engines.