rbargeron
Well-known member
Lifetime Member
Equipment
L5450, L48, L3250, L345 never enough attachments
Shutting it down at the first bad noise was a good move. The damage may be fixable.
With an engine under load when the oil flow stops, the connecting rod bearings are usually the first parts to be damaged. The bearing shell surfaces melt and re-freeze, sticking to the crank sometimes bending the connecting rod - it gets rapidly worse. Shell halves can get out of position, climbing over the other half (called a spun bearing). That rod may break. All this takes only a few seconds.
What happens next depends completely on luck. A broken rod can punch a hole in the block - but may not. If the engine is shut down and cools off, there may be damage in one or two bearings but not all through the engine. In some cases, only a connecting rod and bearing shells are needed. The cylinder walls & rings sometimes escape unscathed.
You may not need a whole engine or even a complete rebuild kit unless the engine has a ton of hard hours on it and was due for rebuild before. It could be just a few hundred dollars, even with new piston rings.
A way to approach it would be to assess the damage with the engine block still in the tractor. Obtain and read the WSM. Take off the head, take down the front drive shaft and take off the oil pan. Take off the connecting rod caps and push the pistons out the top. Inspect to see which rods are affected. If its only one or two, the main crank bearings may not be damaged. If the crank turns ok by hand with the rods disconnected the mains are ok. Shop for parts AFTER its known what really needs replacing.
One good feature of Kubota engines is that several models use the same bearing shells and many other wear parts. these guys have decent engine part prices.
If things are worse than expected the crank will have to come out too (with engine out of the tractor) But it may not come to that.
With an engine under load when the oil flow stops, the connecting rod bearings are usually the first parts to be damaged. The bearing shell surfaces melt and re-freeze, sticking to the crank sometimes bending the connecting rod - it gets rapidly worse. Shell halves can get out of position, climbing over the other half (called a spun bearing). That rod may break. All this takes only a few seconds.
What happens next depends completely on luck. A broken rod can punch a hole in the block - but may not. If the engine is shut down and cools off, there may be damage in one or two bearings but not all through the engine. In some cases, only a connecting rod and bearing shells are needed. The cylinder walls & rings sometimes escape unscathed.
You may not need a whole engine or even a complete rebuild kit unless the engine has a ton of hard hours on it and was due for rebuild before. It could be just a few hundred dollars, even with new piston rings.
A way to approach it would be to assess the damage with the engine block still in the tractor. Obtain and read the WSM. Take off the head, take down the front drive shaft and take off the oil pan. Take off the connecting rod caps and push the pistons out the top. Inspect to see which rods are affected. If its only one or two, the main crank bearings may not be damaged. If the crank turns ok by hand with the rods disconnected the mains are ok. Shop for parts AFTER its known what really needs replacing.
One good feature of Kubota engines is that several models use the same bearing shells and many other wear parts. these guys have decent engine part prices.
If things are worse than expected the crank will have to come out too (with engine out of the tractor) But it may not come to that.
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