Has anyone rebuilt their Kobuta tractor engine using one of the ebay rebuild kits ?

westcliffe01 · Nov 1, 2020

So I have a Kubota M4500DT which is a mid 70's 55hp utility tractor. It has no hour meter but given the age of the machine I am assuming it has at least 6500 hours on it.
It has low compression which makes it hard to start, but once it is running, it does everything I need it to do. Oil consumption is low, although given the vast amount of oil in the sump, perhaps it it higher than I think...
Looking at ebay, there are complete rebuild kits for about $800. These have sleeves, pistons, rings, valves bearings and gaskets. It seems relatively inexpensive, but what is the quality of these parts ?
I would probably replace the clutch at the same time, if the tractor has to be split to do the work on the engine.

Does anyone have experience with any of these rebuild kits ? So far I have $8500 into this tractor and generally I am happy with it. I'm hoping that restoring compression and replacing glow plugs and injectors will improve starting.

Thoughts ?

fried1765 · Nov 1, 2020

westcliffe01 said:
So I have a Kubota M4500DT which is a mid 70's 55hp utility tractor. It has no hour meter but given the age of the machine I am assuming it has at least 6500 hours on it.
It has low compression which makes it hard to start, but once it is running, it does everything I need it to do. Oil consumption is low, although given the vast amount of oil in the sump, perhaps it it higher than I think...
Looking at ebay, there are complete rebuild kits for about $800. These have sleeves, pistons, rings, valves bearings and gaskets. It seems relatively inexpensive, but what is the quality of these parts ?
I would probably replace the clutch at the same time, if the tractor has to be split to do the work on the engine.

Does anyone have experience with any of these rebuild kits ? So far I have $8500 into this tractor and generally I am happy with it. I'm hoping that restoring compression and replacing glow plugs and injectors will improve starting.

Thoughts ?

I have experience with buying a Ford clutch kit on E-Bay.
It was a BAD IDEA!
I got the opportunity to do the clutch replacement again.....after only 2-1/2 operating hours.
My philosophy now is: No E-Bay internal parts,..... engine, or transmission!

westcliffe01 · Nov 2, 2020

Is it not true that virtually all compact tractors are now built in China ? Their engines too ?

I see that the same manufacturer is selling rebuild kits for the Cummins 5.9 engine (for a similar price) and there are some positive reviews on those kits.

DK35vince · Nov 2, 2020

westcliffe01 said:
Is it not true that virtually all compact tractors are now built in China ? Their engines too ?

No, its not true

westcliffe01 · Nov 2, 2020

Messicks does not list a rebuild kit for the engine, you have to piece it together from individual parts, but here is what the start of that looks like :

Item Description ea qty total
Kubota 15201-02310 LINER, CYLINDER $103.69 6 $622.14
Kubota 1C010-13560 GUIDE, VALVE (EX $10.32 6 $61.92
Kubota 1G896-13580 GUIDE, VALVE, IN $9.10 6 $54.60
Kubota 15221-13110 VALVE, INLET $25.81 6 $154.86
Kubota 15221-13120 EX/VLV $25.81 6 $154.86
Kubota 15221-13153 SEAL, VALVE STEM $5.30 12 $63.60
Kubota 15201-21110 PISTON $111.70 6 $670.20
Kubota 15201-21052 RINGS $90.58 6 $543.48
$2,325.66

No bearings, gaskets or seals in there yet. The price of the liners, pistons or rings individually is about the same as the entire ebay kit. The valves seem cheap enough that if I needed to replace any I could go with genuine parts The guides also are pretty inexpensive as are the valve stem seals. I just think that I am probably not going to get around replacing the liners and pistons and rings and that is the majority of the expense. The US based aftermarket parts places dont seem to stock any pistons, liners or rings.

David_Kb7uns · Nov 3, 2020

Look at Kumar Bros Search Result

Ken · Nov 3, 2020

Six years ago had an L3600 Kubota and the engine was hard to start. The compression was good. looking for why checked the valve setting and reset several. way to loose to and it made a different difference in starting. a neighbor has owned it since and still reliable in cold mornings to start.
Might check and see if this is the cause.
ken

Langanobob · Nov 3, 2020

Did you test the compression to confirm that it’s low? Like Ken says, it could be something relatively simple causing the hard starting.

fried1765 · Nov 3, 2020

David_Kb7uns said:
Look at Kumar Bros Search Result

There have been complaints here on TBN about Kumar Bros.

westcliffe01 · Nov 3, 2020

Bob, based on the fact that the starter spins this engine like a turbine and cranking does not result in heating the cylinder the way you get with a high compression engine, I do believe it is a compression issue. I run my battery down much faster cranking my D1105T 3 cylinder engine than I do with the S2600 6 cylinder engine and im sure that is not the way it should be...

I have not tested the compression, I would need to get some equipment to do that. Does one pull an injector or a glow plug to do a compression test ? I should probably replace the glow plugs anyway because I am sure that they are original...

Langanobob said:
Did you test the compression to confirm that it’s low? Like Ken says, it could be something relatively simple causing the hard starting.