My wrist pins on M4500DT S2600 engine have some have some play at the end when in the rod bushes. They measure within ½ wear allowances of what the manual says which I think is a bit much .15mm .0059” is the specs attached diagram allowance. There is some slight wiggle at the end of the pins in the rods. One site although it was about Volkswagens, said if the pin can slide through the rod with gravity there is too much play.
They say it should be neat enough to not fall through with gravity. My pin will do this clean but if I put some engine oil on it, then it still slides through but takes two seconds or more to slide through. I thought buy new genuine Kubota wrist pins and bushes because they are not too expensive. The manual says to press the old ones out and the new ones in, but does not mention having to have them honed or reamed. Does anyone know if new bushes for these have to be reamed before installing? The manual states new ones are tinned. (diagram)
The reason I stripped the engine is there was a knock which I couldn’t diagnose, the rod shells are worn, not spun or ruined but I wouldn’t think enough to cause the knock. I am putting new ones in. The only thing I have found so far was a tappet has a slight groove in the bottom so would not have been turning on the cam. Perhaps the cause of the knock?
One of my injectors is not fully atomizing and has the slightest spray to one side when on the injector tester. I did not think that this was the cause of the knock because it sounded deep in the engine, but other OTT comments beg to differ. I just want to be sure it is not a wrist pin knock or piston before I put it back together. There is no piston scuffing at all and they look and measure good except for ring wear. Pins fit nice and firm in pistons, you can push them from circlip to circlip with finger force but are firm in pistons, floating pins not press fit. Heat piston in oil as per manual spec and they go in nicely firmly.
Worst pin measures 22.98mm .905” and bush measures at worst part 23.05mm .9075” with slight taper wear which can be seen on photo, but can’t be felt and no difference in measurements. The oil in this tractor has not been changed before I had it and I am now cleaning everything because contamination has gone through the system.
They say it should be neat enough to not fall through with gravity. My pin will do this clean but if I put some engine oil on it, then it still slides through but takes two seconds or more to slide through. I thought buy new genuine Kubota wrist pins and bushes because they are not too expensive. The manual says to press the old ones out and the new ones in, but does not mention having to have them honed or reamed. Does anyone know if new bushes for these have to be reamed before installing? The manual states new ones are tinned. (diagram)
The reason I stripped the engine is there was a knock which I couldn’t diagnose, the rod shells are worn, not spun or ruined but I wouldn’t think enough to cause the knock. I am putting new ones in. The only thing I have found so far was a tappet has a slight groove in the bottom so would not have been turning on the cam. Perhaps the cause of the knock?
One of my injectors is not fully atomizing and has the slightest spray to one side when on the injector tester. I did not think that this was the cause of the knock because it sounded deep in the engine, but other OTT comments beg to differ. I just want to be sure it is not a wrist pin knock or piston before I put it back together. There is no piston scuffing at all and they look and measure good except for ring wear. Pins fit nice and firm in pistons, you can push them from circlip to circlip with finger force but are firm in pistons, floating pins not press fit. Heat piston in oil as per manual spec and they go in nicely firmly.
Worst pin measures 22.98mm .905” and bush measures at worst part 23.05mm .9075” with slight taper wear which can be seen on photo, but can’t be felt and no difference in measurements. The oil in this tractor has not been changed before I had it and I am now cleaning everything because contamination has gone through the system.
