Crank damage?

[barkev]

Guys I need opinions.
Mechanic passed away tragically, cancer
mId-engine build. He didn't tell anyone!
.
So the pix...he did the top end, and I'm assuming he did the rod bearings because they looked new when I pulled the crankcase and had them out.
The reason I pulled them? Oil wasn't getting to the top, at first I thought oil pump ... then spun bearing and there it was!
If you compare the baddie with a good one - there's a tiny hole for lubricant - on the bad one the hole doesn't go all the way through. I'm guessing that's was caused the scoring.
So I replaced them all. But should I grind the crankshaft as well ?
Or did I dodge the bullet on the bottom end?
.

 

[Shayne]

I recently spent some time assisting a pro rebuild a Kubota engine that got so hot it melted 2 pistons . When it came to the crank he wanted my opinion before offering his own , I figured that if relatively new shells (the engine had been rebuilt badly by a pro 2 years previously ) were in fair shape then the crank was likely good . He agreed and we chanced it . Had the shells been damaged I'd have taken the crank to the machine shop who honed the cylinders .

 

[Towpack]

If you can't see or feel any damage on the crank pin I'd say just go with new bearings. Compared to the crank pins, bearing metal is quite soft and sacrificial.

 

[barkev]

If you can't see or feel any damage on the crank pin I'd say just go with new bearings. Compared to the crank pins, bearing metal is quite soft and sacrificial.

Yeh...plus all new components. I didnt drive on those bearings, I replaced them right after checked the oil. New oil's clean. I still have a mysterious knock down there so something ain't right, some clearance or something.

 

[barkev]

I recently spent some time assisting a pro rebuild a Kubota engine that got so hot it melted 2 pistons . When it came to the crank he wanted my opinion before offering his own , I figured that if relatively new shells (the engine had been rebuilt badly by a pro 2 years previously ) were in fair shape then the crank was likely good . He agreed and we chanced it . Had the shells been damaged I'd have taken the crank to the machine shop who honed the cylinders .

 

[barkev]

Sounds like it ran hot. Roger may have machined the crank, but dunno. Can't ask him now...RIP

 

[Towpack]

To be sure in your own mind it looks like you going to have break out the micrometer and the Plastiguage to check for ovality and the running clearance. A bit of a faff but it's what your mechanic would have done if he was in the same situation.

 

[Shayne]

A loose shell bearing would knock , we took turns at the end of each day checking the other had tightened everything to torque . A bad injector might cause piston knock maybe ?

 

[frank rabbets]

Looks like the soft surface of that shell has smudged over the steel body blocking the oil hole.

Not sure what you say the cause is.

The crank pins are very hard so if the soft shell of the bearing has not gone down to the steel then it should be OK.

Also if the crank pin does not show damage it should be OK. I would buy a micrometer and check the pin for size/wear.

You can use Plastiguage but Toyota parts are made very accurately so I missed that step. Just make sure the crank turns freely after every bearing is fitted.

 

[barkev]

Looks like the soft surface of that shell has smudged over the steel body blocking the oil hole.

Not sure what you say the cause is.

The crank pins are very hard so if the soft shell of the bearing has not gone down to the steel then it should be OK.

Also if the crank pin does not show damage it should be OK. I would buy a micrometer and check the pin for size/wear.

You can use Plastiguage but Toyota parts are made very accurately so I missed that step. Just make sure the crank turns freely after every bearing is fitted.

Hey frank.
Cause? I'm guessing the lubricant wasn't getting in, so no oil surface between the bearing and the journal metal. The scoring's not too bad and next to no miles on the rebuild so we're just going to clean up the journals and retorque and see what happens. Thnx.
.