where do all the duramax pistons crack?

[Devan Manis]

In an effort to keep the dodge common rail piston melting thread on topic i have started this thread to ask a quick question. Where do all the duramax pistons crack? Is there a common area or are they pretty random?

 

[paint94979]

In an effort to keep the dodge common rail piston melting thread on topic i have started this thread to ask a quick question. Where do all the duramax pistons crack? Is there a common area or are they pretty random?

the LBZ/LLM piston crack at the wrist pin

 

[malibu795]

the LBZ/LLM piston crack at the wrist pin

same with LB7/LLY crack at the wrist pin running parrellel

 

[Diesel Tech]

Most every cracked Duramax piston will have a hole, be it small or large from the oil cooling galley into the bowl at the beginning of the crack. The hole will be in line with the oil squirter fill hole or the exit hole from the underside of the piston. It will then follow along parallel to the wrist pin until it exits the edge of the piston.

 

[Devan Manis]

well thanks for the speedy answers, does any one have pictures?

 

[Purehybrid]

thats from Gasout's rebuild

 

[BluegrassDiesel]

Has the exact cause of what makes the pistons crack been determined?

 

[bsmith]

Has the exact cause of what makes the pistons crack been determined?

Not enough material in that area, is what i was told.

 

[JustinD]

Less common to see LB7 pistons crack right? Thats why they use them in the LBZ/LMM rebuilds.

 

[paint94979]

Less common to see LB7 pistons crack right? Thats why they use them in the LBZ/LMM rebuilds.

LB7 and LLY pistons are the same... the LBZ/LMM pistons are an asian brand piston as opposed to Mahle Pistons like on the LB7/LLY

 

[Devan Manis]

So the spray pattern on the picture kind of missed the bowl...

 

[malibu795]

Not enough material in that area, is what i was told.

some were there is a profile view of the LB7 piston on diesel place baried int he archives.. see if i can find it.

the cone is 158* stock has that flower pattern ...

the lip is more for emission than anything.. and it necks down to 1/8 radius. which heats up faster then the rest of the piston and it si the farthest away formn the oil coolling passage under the crown. it usually goes first and the rest follows mush like punch a hole in steal with a blow tourch.

 

[malibu795]

got some cut aways for you to look at.. these are from late 06 when we start loosing pistons

 

[bsmith]

some were there is a profile view of the LB7 piston on diesel place baried int he archives.. see if i can find it.

the cone is 158* stock has that flower pattern ...

the lip is more for emission than anything.. and it necks down to 1/8 radius. which heats up faster then the rest of the piston and it si the farthest away formn the oil coolling passage under the crown. it usually goes first and the rest follows mush like punch a hole in steal with a blow tourch.

Thanks.

My buddy's lbz pistons looked like roasted marshmallows, kinda like some of the CRs.