300Tdi engine knock

I pulled no. 4 big end.
The bearing is 0.01 oversize
The bearing has been installed cockeyed, with the ends not aligned, this has caused a lot of wear on the sides of the shell.
The widest part of the bearing shell is 5mm wider than the most worn part.
I suspect the metal in the sump is big end bearing.
I've rechecked the others and I don't think i can feel any play in them.
There is close to a mm of end float in the crank.
The big end journal is quite scored.
At this stage I haven't pulled any of the others or any of the mains.
I can't see anything being done to this motor in the car.

Thanks for everyone's input to this.

Tony

you could try a quiky linish by hand on the crank, fitting a new 10 thou big end bearing then plastigauging it. then do the rest and the front and center main. IF they come up ok the rear is possibly ok so you can leave it.

But the correct answer is a rebuild.

Quote:

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Originally Posted by Blknight.aus

you could try a quiky linish by hand on the crank,

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Done that using an old speedo cable inner wrapped a few times around the journal.

thats one way, a 95% wrap with wet and dry then the wide plastic pallet strap also works well.

Didn’t have plastic pallet tape when I did it ☹️ It would be about 45 years ago.

Well the motor is out and in bits.

All the big ends are on their last legs, showing wear and bearing material "pulled" from the shell, they are all 0.010" undersize.
Mains all showing wear, but not the damage the big ends have, they are also 0.010" undersize.

All four pistons have significant damage from hitting the inlet valves, they are also all cracked. All 0.020 oversize.

The bore of no. 4, the only one I have the piston out of at the moment, is showing hone marks round half its circumference and scoring round the the other half.

Curiously the valves don't have the same marking as the damage on the pistons.

Tony

Edit
Changed piston damage to inlet valves.
Seems I don't know an inlet from an exhaust valve. (Well I do now)

Quote:

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Originally Posted by TonyC

Curiously the valves don't have the same marking as the damage on the pistons.

Tony

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Could be the result of a previous belt failure. PO probably just redid the head.

Quote:

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Originally Posted by Tins

Could be the result of a previous belt failure. PO probably just redid the head.

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All four pistons have near identical inlet valve damage, no evidence of an exhaust hitting any piston.

That seems unlikely from a broken belt, seems more likely a mistimed cam.

But I really don't know, happy to hear anyone's ideas.

Tony

Edit
Confused my inlet and exhaust valves

The injection might have been late or really bad injection..

The bore damage is from loss of lube from the piston squirter which is probably due to the mushed bearing or having the rod installed the wrong way around.

The piston damage is from the inlet, not exhaust valves.
Probably makes no difference.
I've edited the posts about it for clarity.

Tony