crankshaft construction

[yaris9876]

I was reading about a new process for large ship crankshaft casting and it seemed to
be saying the throws were cast independently and somehow joined to the crank instead
of casting as 1 unit and milling the whole thing. Do any car cranks have throws that
are joined onto a crank and if so how do they attach them..??

[invader166]

I've heard about that process. Definitely sounds like it'll lower the production costs! I guess we'll have to see how well they perform long term, but with all these advancements in design and construction, I wouldn't be surprised if they offer a comparable amount of service life.

As for the same process being used for construction of automotive engine crankshafts, I think it's still in the developing stage?

I'm sure that one of, if not the biggest challenge the're facing, is creating a unit that can resist such a high number of bending moments as compared to a marine unit. That's mainly because almost all marine diesel engines in use today are either slow speed (80 RPM-120 RPM) or medium speed (250 RPM-800 RPM)

[Yaristeve]

That's old tech. Crankshafts for motorcycles were pressed together back in the 70s, especially 2-strokes. I think Kawasaki was one of the last to do this on four-strokes. This allowed the use of roller bearings instead of plain bearings.