The shift from needle/roller bearings to bushings on aftermarket rocker arms has been going on for a while.
The way I see it, to the average car guy a ball bearing is better than a journal bearing (bushing). Rolling, not sliding, right? When I give tours in our hydro plant that's one of the first areas of discussion because most assume rolling element bearings are better.
SO, when aftermarket rockers moved from Isky and Crane cast rockers, the tendency was to go straight to the rolling element bearing. It has taken decades for aftermarket designers and manufacturers to be convinced that the bushing is better for this application, and to dare to put it on the market where they had to convince the consumer that the bushing was a better way.
So !surprise! now the consumer is starting to ask, "Why are the manufacturers using those crappy needle bearings when everyone knows bushings are better?" 15 years ago they couldn't have sold them.
R.
Interesting points. If you look at extreme high speed shafting, you will typically find a sleeve (bushing) style bearing. The ball/needle rotational speed is just to high for a rolling contact bearing. At least that's how it was explained to me by a Sundyne engineer.
