RaceProfessor

I'm a bit new to the M113K platform and I've read the stock motors' longevity are greatly reduced at around the 600whp range and start popping over that threshold. My question is what is failing over the 600whp mark, ring lands, bearings, rods, etc sufficient the tune was solid?

Anyone making 550+whp that's got some mileage on their set-ups? I would certainly like as much power as the car can muster but reliability takes precedence over ultimate output. Thank you for anyone's input.

Sulaco

As far as I know the common failures are ringland and specifically in cylinder 8.

I hate Facebook, but there's a couple big AMG groups on there with thousands of people who are currently still doing lots of m113k builds. Might get more info there, combined with a bunch of salt and extremely unhelpful comments that make people not want to be a car person anymore.

SICAMG

Pistons for sure. First the ring gaps are tight so under high heat and pressure they expand and but up against each other...than the lands break. Second the pistons , although are Mahle and great quality, are cast and will not hold up to long term abuse and that could be years for many including my self.
Cylinder 8 is not a problem really. It's the fueling to that specific cylinder that causes problems. Like Sulaco said lot's of people building them just have to hunt them out. I learned a lot from Chris, Sirboostalot and this guy really knows his stuff.

kevm14

Sounds more or less like the LS. If you gap the rings and tune carefully they can handle 800+ wheel or even 1000. Bad tunes and stock ring gap means stuck down around the 500-600 mark.

My opinion is if the rings butt and it breaks a land, that's not because of "weak pistons.". Similarly, detonation can destroy even race pistons. They'll just handle more abuse before finally becoming vented.

SICAMG

Hot Rod just dynoed a 6.0 LS with 240,000 miles and made 1,440 hp with bigger ring gaps and add on parts. Bad *** for sure those Ls's !!

Sulaco

Does this imply that it's as simple as bigger ring gaps and that fixes the 700hp threshold on a stock M113k?

SICAMG

Answer is .....Yes....No. Many other factors involved as well but the ring gap is a big deal.

Sulaco

Oh yeah, didn't they also do the same with adding a turbo and some parts to a mostly stock 5.7 hemi truck motor? I want to say they were right over 1400hp as well

SICAMG

It's crazy what these engines can make today with turbos !!

RaceProfessor

I had an LS3 C6 but the Vette tax made everything very expensive even compared to a Benz. I wanted to do so many different projects, a 5.3 turbo truck, a fbo Coyote, etc. but this car suits me best with its features.