[Texas Diesel Guy]

Hi there, well have you heard of cranks breaking? I've run my super-comp dragster with a 500 inch chevy motor in it and it was balanced, aluminum rods, short pistons 14.5/1 compression and it ran like a damn! I lost two valves at different times that caused me to sleeve the cylinders and finally was running too much nitro and stuck a rod to the crank and sawed the block in half, but never broke a crank! In fact I sold this car to a guy who's going to pull the engine down and polish the crank and have it mag'ed and possibly run it again! I've had the snout brake off cranks before but that's from loose dampers and I've seen broken cranks in motors that are blown up, but never in a normal engine. I'm new to diesels so if there's a problem with cranks, I'm interest too, but I can't imagine, especially if you're going to balance the motor and lets face it your going to turn it what 2300 to 3500 RPM's while I was turning that 500 inch big block chevy 9000 RPM and didn't break a crank.
racerleo
Oh, by the way, I had an auto repair shop for 35 years and am now retired! Ya Hooo!!!

Geez, somebody's been waiting to blow their whole wad on one post.
Yeah, diesels are a different animal and they break cranks way more often than gasolines do. Some are worse than others of course, like Dodge 3.0 ECO diesels and LMM Duramaxs which are notorious for it for different reasons. The Dodge ECO diesel was prone to spin main bearings, leaving main journals unsupported which allowed the crank to flex. The LMMs failures were blamed on over hardening of the cranks and no other version suffered such a high failure rate. The 6.2/6.5 crank failures are mostly due to harmonics.