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cumminsdr, Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 3653
Experience:  All types of Cummins applications
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N 14 number 5 cylinder keeps busting piston

Customer Question

N 14 number 5 cylinder keeps busting piston
Submitted: 1 year ago.
Category: Medium and Heavy Trucks
Expert:  cumminsdr replied 1 year ago.

How is the piston failing?(Cracked,Melted,Burnt,ect..). Do you have pictures? Were the injectors and heads replaced at OH? who did the repair a Cummins authorized shop? what is the engine serial number and part number of the Pistons used if you have that info.

Customer: replied 1 year ago.
serial 11828182. 2 piece piston, this is the second time it has busted the skirt off the piston. first time we chocked it up to aftermarket parts but this time these were genuine cummins piston kit. we did the inframe in house as well as the first failure repair. i will get some pictures of it as soon as possible.
Expert:  cumminsdr replied 1 year ago.

Ok thanks, ***** ***** help.

Customer: replied 1 year ago.
Expert:  cumminsdr replied 1 year ago.

Is the center of that piston jet black underneath? It looks like it. Was the Piston cooling nozzle intact and checked for plugging or cracks or broken? I see excessive scoring as well. Thinking the piston overheated from a failed piston cooling nozzle and the piston assy swelled up and made contact with the liner. or there was a defect with the skirt that allowed it to contact the liner and break than cause the scoring from still running Its tough to see the whole picture here. Does the oil filter show signs of metal from the piston failing prior to the CAT event? you would have to get an oil sample from the filter by cutting it open and checking the media for metal. If it is present han the oil was circulating the debris prior and it was not an instant failure ect. Let me know. Since you used Cummins parts you can call Cummins and have a DFSE come out to your shop and perform a full failure Analise on the failed component. The DFSE is a Field Service Engineer and works for The Cummins factory. He can be reached at your local Cummins Distributor,. NOT a dealer I can also look up your local distributor with your state and town .Please don't forget to rate my service.

Customer: replied 1 year ago.
sorry for the delay. i checked the piston, it is still steal colored not black at all. new development though. installed new piston kit,oiler and oil pump. reassembled everything and fired engine, had a horrible knock. unplugged injector 5 and noise quit. swapped #5 and #6 injectors fired back up ran smooth and quiet. after warming up knock started coming back but no where as loud or bad as original until around 1000 rpm then it gets louder. now unplugging injectors has no effect on the noise at idle or high idle. i hate to go buy a new injector and that not be the case.
Expert:  cumminsdr replied 1 year ago.

You will need Cummins Insite to assist in locating the failed injector. The injectors should of been replaced at the original overhaul as they only have a life span oof about 500k miles. With insite you can do a cutout test and an cylinder performance test to check each cylinder also now as an accelerated base cut out test.

Expert:  cumminsdr replied 1 year ago.

Any luck, Just following up, Please don't forget to rate my service

Expert:  cumminsdr replied 1 year ago.

Just following up, Please don't forget to rate my service

Expert:  cumminsdr replied 1 year ago.

Please don't forget to rate my service.

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