madaz matt

i heard that this guy put needle bearings in a holden 186 (sooooo sory for talking about piston engines especialy holdens) it reved to 9000rpm!!! could you do this with the eccenteric shaft and rotor bearings i know that alot of machiening would have to be done but it would be worth it.

maz_side

why would you lol big turbines etc that spin alot faster than that use white metal bearings because roller type bearings just cant handle it and because a stock rotor bearing uses the same principle as white metal bearings althogh they are not white metal i cant see why you would want to do this.

madaz matt

sooo much less friction

Nospig

Revolution in japan make stationary gears with needle bearings and shafts to suit , ther are pics on there web site Revo tune or something.

mazdaspeed7

There is no metal to metal contact with stock type engine bearings, the ecc shaft is supported by the oil film. Needle bearings require metal to metal contact, and they wear. Needle bearings are used when theres a load bearing requirement beyond what the oil film can support in conventional engine bearings.



It may have a place in race engines, but how often do you want to tear down your engine to replace the bearings?

Lynn E. Hanover

The smaller rotaries that run air cooled rotors do use roller bearings in the rotors. There are kits that include 2 piece cranks and a modified center iron that add a roller bearing to the Mazda two rotor engine (13B).



So it does work just fine. It is pricy as hell and is only use where required. Like in aircraft APUs or drone engines, or drag racing Mazdas.





Lynn E. Hanover

j9fd3s

one of the problems with the bugattis from the 20's and 30's (some have roller cranks, and cockpit adjustable damping, etc etc) is that during accelerations of the crank, the rollers/***** spin in the races, and wear em out. its good in those cars for a constant speed



i'm sure bearings are better now, but its not a new idea

C. Ludwig

Two-stroke engines use roller bearings on the crank and needle bearings in the rod small ends. There's no lubricant pumping through the bearings so it's a somewhat mandatory alternative. In watercraft racing 200+hp is very common from 1200cc. Snowmobiles are at the forefront of two-stroke technology and always produce more power per cc than watercraft. I've heard the arguement that caged bearings couldn't support the HP as well as journal bearings but it would appear that is bunk. ??

madaz matt

thanks guys so the shont answer is that it can be done but its hard,expensive and not very beneficial

ColinRX7

It would be more beneficial to look into increasing film strength of the oil you use.



Off-shelf oils I have seen tested at max of generally 50,000 psi film strength, and I have witnessed additives increase film strength to over 200,000 psi without use of any solid products that could cause buildup (teflon, etc).