Why do crankshafts use plain bearings instead of roller bearings?

[Gillbot]

Timken actually has a place here, but I have no idea if they're hiring. Pretty much polar opposite of Phoenix.. 😛

Meh I looked around a little and found electrical engineer...didn't see anything on mechanical, though.

http://www.manufacturingworkers.com/job.asp?id=23860121&aff=925A0F9A-7C85-4AAD-A3D2-5E5C81892E2F

We are not hiring, if we do it's very limited.

http://timken.com/en-us/careers/Pages/default.aspx

 

[Ferengi-Farang]

Ferengi-Farang... Please note this thread is 8 years old please either respond to much newer threads 1 year or less old or simply start a new thread of your own...

AT Moderator
Bartman39

as above

I used to have a Suzuki motorbike in 1986, an end-of-production model. The GSG 1100 touring bike, derived from the GSG 1000 itself deriving from the GSG 850, which was a direct evolution of the first 4-stroke engined Suzuki big bike GS 750.

As a reputable 2-stroke engine builder, Suzuki had finally to u-turn around 1977-1978 to more fuel efficient 4-stroke engines, which it did with those long-production lines, the GS 400 and the GS750.

It was a major, if not brutal, change for the builder. They used their 2-stroke tech & foundry knowledge to produce perfect modern engines at first attempt - hence their exceptional longevity in production as demonstrated above.

It turned that using ball bearing supported crankshafts made for a smoother transition for Suzuki, and they reverted to soft metal journals much later on, when their tech level reached that of their competitors, installed since long in the 4-stroke tech, like Honda. It was also a way to reduce engine width, along with the now common replacement of driven accessories behind the block.

I remember having seated on a bike with one of the widest fuel tanks in the production, but the engine was even way larger...

As an advantage, I figure that ball bearings allow for a nonexistent wear & tear of the metal on startup - especially cold start - where most of it happens. Journals bearings start dry and cold until pressure builds the lubricating film - that requires some time and favorable temperature.

Regarding bikes, additionally, many owners are lazy to put them on central stand and start with the bike leaning on the side stand, with the engine slanted ; this is not recommended for initial lubrication, so but ball bearings shall help here, IMHO.