78' 300SD turbo diesel crankshaft

Hi, This ted again, still working on rebuilding my turbo diesel 617 engine. The #1 rod journal spun a bearing and is beyond tolerance for re-surfacing and my machinist wants to know if it is possible to build-up the journal and then regrind it to tolerance? This he has done with gas engines, but has never attempted doing it on a diesel crank. Any suggestions?

[stevebfl]

There are four repair sizes to the rods. I would hope this would cover it. I suppose the crank could be built up but all machining on turbo diesel cranks must be followed by a nitride bath, surface hardening. This can only be done at a few places nationally.

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Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

turboSD,

As Steve said, these journals are hardened. This is a diesel engine with 21 to 1 compression, don't even think about reusing the crankshaft without re-hardening the journal. If you do, you will be tearing it down all over again soon, or pulling out the engine to sell it as junk iron.

Good luck,

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Larry Bible
'84 Euro 240D, 516K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles