Originally Posted by
blindsquirrel
The BTR shafts are real 52100 steel the same as real bearing races are made of (and same as Jesel/T&D would use), not 4140 like nearly all of the needle bearing trunnion kits. It's not possible to heat treat 4140 to a level where it will tolerate direct-running needle bearings. 4140 is just not the right material for this and it's frustrating that the public doesn't know any better and the sellers don't care to tell them, they just keep selling the garbage and cashing the checks.
Needle bearings are better as long as they are running on the right material. This is splash-lubed-only, not pressure fed like the big diesels that everyone loves to cite as to why bushings are better.
(and last time I brought this up it got pointed out "yeahbut wrist pin rod bushings are splash lubed and they do fine" and that's someone who doesn't understand that the wrist pin does not rotate in the rod bushing when the engine is running, it rotates in the piston.)