Thread: Broken 300tdi crankshaft

Sorry about the quality, but only have two hands...

Oooh yeah, thats not good!

Ok, an update. Finally got around to sending the new (second hand) crank away to be ground - probably 010, as there is only a slight mark on one of the main journals. The engineer said you might get away without it, but I like to do things once only. Will cost $500. Stripped the block down and measured the bores. All around 15-16 thousands oversize so will be 040. Cost for bore/hone $480.

Will update as I get the parts back and start assembling.

Tom.

Is a broken crankshaft a known problem with these engines?

In another life I had a tractor with a L4 Perkins engine. That broke its crankshaft, and with much rattling I managed to drive it back to the farm shed. It turned out that they were well known for breaking, but it was news to me at the time.

Anyhow, I sourced a replacement used shaft, but I had it x-rayed before installing it. Can't remember if I also had it ground, but I don't think so.

It's amazing what can be achieved in supposed third world countries.

It's amazing what can be achieved in supposed third world countries.

What really surprised me was his modern polishing tool!

I am really intrigued about the hydraulic jack under the lathe. Not sure just what he was trying to achieve, but he may have been trying to measure the deflection, or it is some form of magic stress relieving!

I watched it on YouTube and some of the comments on there are a direct reflection of some people's mental capacity. Going by the number of crankshafts in his shop he must be doing something right!

Originally Posted by Old Farang

What really surprised me was his modern polishing tool!

I am really intrigued about the hydraulic jack under the lathe. Not sure just what he was trying to achieve, but he may have been trying to measure the deflection, or it is some form of magic stress relieving!

I watched it on YouTube and some of the comments on there are a direct reflection of some people's mental capacity. Going by the number of crankshafts in his shop he must be doing something right!

Its a pretty cool process that he is going through. I'm impressed with what he has done. The great thing about Youtube is that everybody is an expert. Interestingly everybody on YouTube are the worlds most proficient welders too judging by the comments on every welding video I've watched.

With the jack, I think he might be rebending the crankshaft. He has machined it all concentric, and welded it while it is concentric, but the welding contracts and distorts everything. The dial indicators will measure the deflection when he is bending the crankshaft, but they're really there to measure the run-out from the crankshaft he has bent it straight again. Once it is straight he will have minimal runout - he then finished off with machining which removes any leftover runout.

I did not notice if he heated the whole crankshaft, both before welding and after. That may have happened as it will help relieve welding induced stresses.

He has some magic square black coloured pad up on the wall behind the lathe. It may be a form of bearing blue, but he is that quick using it I cannot see just what he is doing!