I have replaced worn piston rings and rod bearings in s2600 engine Kubota M4500DT.
No knowledge of the previous life of the tractor but when I got it the oil hadn't been changed for a long time.
I read if under the crown is black then it would have been overheated. Photo under crown is a lacquer brown but in the centre above wrist pin is black. Black patch about 1/2-3/4 inch in size ( its a bit hard to see in photo). I am also concerned this may have caused the mottling at the side of the wristpin.(or water) Third photo is macro of some micro pitting. This is the worse piston, but If I replace one then I replace all. The problem is its expense of $600 I would rather not spend if the pistons have some life left in them. I have cleaned and flushed the block radiator etc, so It shouldn't overheat again if that's what's happened. Ring lands look very good with no micro welding. Ringland's are in spec and the pistons measure up to spec. There is no scuffing of the skirt except a few faint minor lines. The carbon patch from combustion would clean off but I left it there to know the orientation of the piston. Is there life left in them or would overheating have annealed them and too risky to install them?
Anyone with experience with this your advice is appreciated.
No knowledge of the previous life of the tractor but when I got it the oil hadn't been changed for a long time.
I read if under the crown is black then it would have been overheated. Photo under crown is a lacquer brown but in the centre above wrist pin is black. Black patch about 1/2-3/4 inch in size ( its a bit hard to see in photo). I am also concerned this may have caused the mottling at the side of the wristpin.(or water) Third photo is macro of some micro pitting. This is the worse piston, but If I replace one then I replace all. The problem is its expense of $600 I would rather not spend if the pistons have some life left in them. I have cleaned and flushed the block radiator etc, so It shouldn't overheat again if that's what's happened. Ring lands look very good with no micro welding. Ringland's are in spec and the pistons measure up to spec. There is no scuffing of the skirt except a few faint minor lines. The carbon patch from combustion would clean off but I left it there to know the orientation of the piston. Is there life left in them or would overheating have annealed them and too risky to install them?
Anyone with experience with this your advice is appreciated.
