QUESTION
What was (were) the perceived advantage(s) of full-floating insert-type plain bearings in connecting rods of high performance engines? I ask this past-tense because the last time I saw them advertised (by Potvin, Moon, Fobert, and maybe others) was about 1957. They were available for then-popularly-raced OHV V8 engines (Olds, Cad, and Chrysler hemi as a minimum). They were similar in design to the stock '32-48 Ford bearings- each insert pair was as wide as the crank journal and served a pair of rods.
I have no experience with them, and want to understand any possible inherent advantage.
REPLIES
PJGD
By floating bearings, are you referring to the type of bush that is/was sometimes used on built-up crankshafts where the typically bronze bush was not pegged to the connecting rod but was free to spin between the rod eye and the crank pin? Early Bristol radial engines used this arrangement, encouraged by Ricardo thinking at the time; the idea being that the bush would precess at roughly half the speed of the relative motion between the journals and also there would be two oil films over which the load would be spread, which in those days allowed a higher load factor before failure.
The heavily loaded roller tappets in our in-line injection pumps had a similar construction at one time, but the pin, intermediate bush, and the roller were all hardened and ground steel.
SOURCE
https://www.eng-tips.com/viewthread.cfm?qid=312524
Above is a snippet.