My buddy has a 555 ci (502 block) that had 45 hrs on it when the crank broke. He bought the crank from my marine mechanic. My mechanic told his engine builder that the crank was used and in good shape and had been magnafluxed (sp). This is what his engine builder told my buddy.
My buddy is all PIss OFF about the crank because the guy that sold him the crank will not do anything for him. I don't disagree with the seller of the crank. That is his call.

MY QUESTION IS:
Was the crank bad or could the engine builder assemblied the engine incorrectly? Example: Not balanced correctly. etc, etc. I know this could be a wide open question but thought I would ask.
The crank was a Lanati (sp)
The owner said the crank let go will cruising at around 4500.

my buddy hit a concrete sea wall at night head on. It damaged the front of the boat and fiberglass work about 6 inches in from the front of the nose. Could it have done engine damage?

I am not inferring that anyone did defective work, or sold bad parts, but I'm not surprised the seller won't do anything for the buyer. Used parts are normally "AS IS" unless a prior agreement is reached, such as contingent upon passing a mag particle test. The engine builder SHOULD have checked it for straightness, size, and magnafluxed it himself, rather than take anyone's word for quality. As to why it broke, hard to say.

you don't even get warranty on new parts when it comes to performance engines.
A few do but most don't.

How the hell did he hit a concrete wall? DAMNIT... I hate it when that happens... did it abruptly stop the motor (like instantly)? How long after rockin out before the motor puked? I feel for the guy, it's a bummer no matter what (especially hitting the wall)...... I hear they hurt stuff

not knowing the surroundings. He said the wall had no lights on it where he was at. He said he had been running about 50 mph and for some reason he backed off and when he did his docking lights shined on the wall. He said he crambed it into reverse. Got it slowed down but not stopped. He was very lucky. He was working out of the windy city so he took his boat from SC with him. He ran it a few hours in SC after hitting the wall. Then he ran it again this weekend. It broke on Monday afternoon late. 1990 27' Carrera.

Slaming it into reverse wouldn't be good for it.

I broke a crank at 7000 rpm once. There wasn't much left that was usable.

I wouldn't think that it was an assembly problem. He did get 45 hours out of it. Besides, what could be assembled incorrectly to cause a crank to break? If the oil clearances are off, it would spin a bearing before snapping the crank. I would bet the crank had a crack in it from the beginning. Maybe forcing the drive into reverse shocked the crank a bit and caused the damage to occur a little sooner, but I think it would have happened anyway.

The crank was used. It was second hand from a third party. And you want the builder to cover it? If you want the part to be covered, then it should have come from the builder. When he supplied the part, he assumed the liability.

That said, a buddy built a engine back in high school. He got about 45 miles on it when the crank broke. Turned out he forgot to torque one of the caps. Must of tried hitting the final torque value in one step.

interesting