In the early eighties, I worked wit

Roller bearing cranks have been tried over and over. At one stage they were popular in hotrodded VW beetles.

The pro's and cons are

The crank must be pulled appart to replace the bearings, or a special split bearing shell must be used.
Rollers can survive with very poor lubrication, hence thair use in 2 stroke engines.
Roller bearings are expensive.
Roller bearings do not tollerate shock loadings as well as a plain bearing.
A well designed and lubricated plain adds very little to the total friction in an engine, so even large improvements here make little difference to the overal friction of the engine.
Plain bearings have less friction than most people think. Unfortunately I cannot find any hard data as it is 30 years since I looked into it last.


Regards
pat

Besides the items Pat listed, I think there'd be very little return on your investment. On a V8, even if we had nearly frictionless main journals (lubricated with liquid helium at a few degrees Kelvin), there's still only 5 of them. While we have 8 connecting rod journals, at least 24 piston rings, a minimum of 16 valves, camshaft, and so on, all contributing to the total frictional losses. On smaller inline engines, where main bearing friction makes up a greater percentage of the whole, then use of ball, roller, or needle bearings may seem more attractive.

BC

I am amused by the trouble some will subject themselves to. There are a few clients of mine that insist on running cams on needle bearings. It's expensive, it's a pain, and it is worth very very little. I preach and sell cost effective power. Plain and simple. However, I would love to be made of so much Money that the extra cost didn't matter. But then, most of us who are made or WERE made of money like me won't get it back unless we pinch our way back.

Shaun TiedeULTRADYNE Arl,TX(stiede@ev1.net)