On 08/17/2019 01:06 PM, micky wrote:
Worth noting that car engines have only sleeve bearings, but they get
long life out of them by making them of special material and by
inserting oil under pressure between the bearing and the rotating
shafts. My guess is that roller bearings and ball bearings wouldn't
work at the high rpm of car engines, or at least they wouldn't work
better, though maybe i'm wrong and some engines I'm not acquainted with
do use them.

Consider what an automotive crankshaft looks like. How do you get the
ball bearings on the journals?

https://www.bmwclassicmotorcycles.co.../crankshaft-2/

Some motorcycles use roller and ball bearings but you are essentially
building the crank out of pieces and the crankcase splits perpendicular
to the centerline of the crank.