Detroit 60 Crank and Bearing Circulating Current damage.

[Shannow]

Detroit 60 used in stationary application.

Suffered severe spark erosion on crank and lower main halves.

Erosion is linear, indicating that the shaft was at rest when it happened.

Anyone seen this in staationary or marine ?

(Anyone seen a faulty block heater dump circulating currents into an engine)

 

[ka9mnx]

WOW! Now that's a head scratchier.

 

[Foxtrot08]

Are you using silver bearings? As well, a rail road engine oil - LMAO 7 11TBN product?

 

[DaveNC]

A friend of mine had to put mains that were eroded in a school bus motor. Rod bearings and all other wear items were perfect. If I remember correctly it was a DT360. The engine had a bad ground, You can run into some crazy stuff. One of the older guys had seen it before and suggested check the electrical.

 

[johnmyster]

A friend of mine had to put mains that were eroded in a school bus motor. Rod bearings and all other wear items were perfect. If I remember correctly it was a DT360. The engine had a bad ground, You can run into some crazy stuff. One of the older guys had seen it before and suggested check the electrical.

Would this suggest that the starter was putting power onto or getting its ground from the flywheel?

 

[crashz]

Is this a stationary generator? Could current have back-fed from something like line power to ground through the engine? The only way I could see that is if the generator head was not separately grounded.

 

[Kestas]

Was any arc welding done on or near the unit? Bad grounding during welding can do this.

 

[OM617YOTA]

Was any arc welding done on or near the unit? Bad grounding during welding can do this.

What came to my mind too.

 

[Shannow]

thanks all, no, no welding without specific precautions given that it a nat gas site.
No evidence of currents back from the GT/Gen.

block heater is on the oil cooler housing, and was found failed with a badly burned out plug, indicating a fault to earth (coolant chamber)

Duty cycle is 2 minutes idle, 9 minutes full load, then stopped...so steering them towards lower W CK-4 lubes

 

[Foxtrot08]

thanks all, no, no welding without specific precautions given that it a nat gas site.
No evidence of currents back from the GT/Gen.

block heater is on the oil cooler housing, and was found failed with a badly burned out plug, indicating a fault to earth (coolant chamber)

Duty cycle is 2 minutes idle, 9 minutes full load, then stopped...so steering them towards lower W CK-4 lubes

The block heater certainly could have led to your issues.

Do you have a time frame of how long it may have been bad before it was discovered?

 

[Shannow]

First they knew was a failed engine, then identified the burned plug...most likely route.

 

[Kestas]

I believe there are ways to chase down stray currents in a unit. I know it's done in the roller bearing industry.

One more thought... can it possibly be a cavitation problem? Diesels sometimes suffer cavitation issues. Arcing would result in reformed martensite (white etching) in the damaged area.

 

[Hohn]

Detroit 60 used in stationary application.

Suffered severe spark erosion on crank and lower main halves.

Erosion is linear, indicating that the shaft was at rest when it happened.

Anyone seen this in staationary or marine ?

(Anyone seen a faulty block heater dump circulating currents into an engine)

Yes. Saw on a one or our stationary gen sets.

This is why proper bonding and grounding is so critical. Current flowing through the bearings will destroy them.

 

[Fabulous50s]

It certainly sounds like the generator was finding ground through the crankshaft. This could still happen due to improper neutral/ground bonding and possibly voltage drop across a loaded neutral.

Id have a very hard time thinking an (assumed) 120V block heater would do this. The engine block should have a large ground (bond) through the generator head. No current would flow through the rotating assembly even with a heating element leaking current to ground.

 

[userfriendly]

Are you using silver bearings? As well, a rail road engine oil - LMAO 7 11TBN product?

Search EMD silver bearings. As far as I know they are wrist pin bearings.

 

[PontiacHO]

Engine electrical system may have been grounding through the engine, not ground cables. I’ve seen bad grounds eat transmission bushings back before the addition of ECMs and like components.

 

[Foxtrot08]

Search EMD silver bearings. As far as I know they are wrist pin bearings.

Yeah I just left the wrist pin part out. But yes, they’re the wrist pin bearing, typically. There are some silver / lead bearings out there. But I think they’re mostly faded off. Way back in the day, silver was used more as a coating in other engine parts.

Just an important question to ask. As sometimes you need to go with a non-zinc product.

 

[Chris142]

Engine electrical system may have been grounding through the engine, not ground cables. I’ve seen bad grounds eat transmission bushings back before the addition of ECMs and like components.

70's Camaro shifter cables and Dodge Omni wheel bearings come to mind.