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Old 12-25-2013, 11:11 AM   #1
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Diesel Rebuild

This may seem like an odd question; my Lugger has just gone through a complete rebuild, sleeves, pistons, cam, head, manifold, water pump and new bearings on the crank. My question is: shouldn't the crank have been sent out for turning if new bearings were installed? I've rebuilt a few gas motors in my day and the crank always got turned when new bearings were installed. Is it common in slow turning diesels to just throw new main and rod bearings in?
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Old 12-25-2013, 11:22 AM   #2
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Very normal if the engine hasn't spun a bearing or otherwise suffered main or rod bearing damage.
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Old 12-25-2013, 11:29 AM   #3
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It's fine if the crank was still within specs. Assuming a reputable re-builder, they will have checked. Last year I rebuilt the engine in a '71 Volvo with 350,000 miles on it. The crank was 100% in spec.
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Old 12-25-2013, 11:32 AM   #4
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My memory is that you grind a crankshaft only if it needs it.

If the journals are round there's no need.

Rick would be the one to know.
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Old 12-25-2013, 12:13 PM   #5
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Thanks guys...I feel better. It was a reputable shop in Boston very good name. I just wanted to ask and I KNEW I would get the answer in here. Merry Christmas!
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Old 12-26-2013, 06:58 AM   #6
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Hopefully the checked it for straightness too.
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Old 01-04-2014, 06:27 PM   #7
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If the definition is "Rebuilding", is not the same than "Remanufactured"

Remanufactured means "to bring the engine to its original specs", and includes check and if necessary, machining the crank in a special lathe.
Rebuilding in general is just to change wared parts as required.

For a complex overhaul, checking the crankshaft is always recommendable, and then, block bearings should be according to.
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Old 01-04-2014, 11:47 PM   #8
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[QUOTE=stevensibs;201155] My question is: shouldn't the crank have been sent out for turning if new bearings were installed? QUOTE]

Mate I just rebuilt my Perkins 6.354 Diesel and didn't do anything to the crank other than check to ensure it was straight. There is no need to grind the crank if it didn't nip a bearing. Luckily I didn't grind it because it turns out perkos with grinded cranks tend to crack them at the bearing journals. As long as it had no pitting or anything like that then you should be sweet

Flick RickB a PM. He's the guru for all things mechanical and will give you expert advice based on fact, not just what he thinks he heard somewhere.
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