Hey Guys...What do yall think cracked these pistons? Boost(pressure) or tuning(detonation)? These pistons are from a Nissan Titan with a MP112 and only 6psi. So far we know of 3 folks who have blown motors while using the S/C and not so many folks out there with Titans and a S/C kit. The top 2 are pics are from the same truck and the bottom 2 are from a different truck both using the MP112 with a Stillen piggyback that comes with the kit. The reason for my concern is I also have a S/C Titan which is making a bad tapping noise from the bottom of the motor, the same noise the vehicle in the top 2 pictures was making. The piece that broke off in the top 2 pics was trapped in between the piston rings and that’s what caused his tapping noise. I am the very 1st Titan owner to go against the grain and use larger injectors and a custom tuned ECU for more flexibility with tuning vs using the piggyback and the extra injectors. When my motor started tapping I was data logging religiously, my AFR was 12 flat and my timing peak was 25 degrees BTDC. I also did not notice any detonation when my motor started making this noise.

 

Broken rings/ringlands are an indication of extreme cylinder pressures. Was the boost turned up? Tank of bad gas?

 

Thanks for the reply. This was only @ 6psi on all motors...I don't think we all had bad gas..lol! Does this just look like weak pistons that can't handle the boost or a truck that was running lean or detonating? The pistons aren't burnt or anything just cracked...

 

well if it didnt ping and you are running normal boost, then they are just weak *** pistons

 

No one with this problem noticed audible signs of detonation....I should have bought a Chevy....lol! What should I get a new next a new body style duramax or the new 2wd 6.2L 6spd Sierra Denali?

 

ring gap too tight, like a tight gap on a non-boosted engine being subjected to boost. Rings meet and break the ring land on the piston.

Jody

 

Detonation usually breaks the piston above the first (top) ring. thats interesting how those broke. Ring gap is a posibility though.

 

one other thing is a lean condition is evidenced also. The area between the upper/lower ring is actually moved down, like the piston got very hot and had boost on top of it.

Jody

 

hard to believe that you would have to rebuild an entire engine just to make it boost friendly

 

I see this all the time,when you get your engine done and re-tuned make sure it is rich enough mid 11s A.F ratio under boost. Rex...........