Geek1945
Well-Known Member
I have always wondered why many 2 stroke engines have closed big end (crank) rods? Or why cranks are pressed at least where the rod journals are. RPM can't be the answer since many others (outboards) use bolt on lower ends. Since the needle bearings can be taped together or use grease to hold them in place during assembly. The center bearing could be needles also with split races. It seems this crankshaft method is outdated considering improved bearing technologies when rods with caps and bolts would eliminate pressing in many cases. Besides a machined steel crank could be drilled for oil channels instead of mixing with gas which would occur anyway. It seems these are purposely designed to be throw-away engines.
- :depressed
