Roller Rotary
 

Could anyone please explain any pros or cons to this idea ? ? ? ?

Attachment 9526

Why bother using them in the first place?

Im not an expert on bearing technology, but im not sure a bearing of that kind can handle the load against it as well. If it was a good idea im sure the small block chevy would of had a crank bearing like this a long time ago. Only reason i meantion a s.b.c crank is because we all know that engine gets all the minds in the world wanting to better it.

I don't think that's correct. Racing teams look to do this for removing friction, however using such bearings causes another issue: Survivability. This is an interesting read: Link

If it goes, what's to stop it from having the needle bearings clogging the oil passages? Where as compared to a regular journal bearing, if it fails, what's going to clog the oil passages?

Where is that from? Website, links, more infor..... is that from a 16X? Seems pretty wide to me.

Less friction = more efficient engine
More efficient engine = more power using less fuel

Or course, the downside is that needle bearings are less reliable versus journal bearings.
I'd imagine service interval is a lot shorter for these needle bearings versus journal bearings.
If you're building a "race engine", this is not going to matter.


-Ted

The big advantage to roller bearings is that they do not suffer accelerated wear for short periods of non-lubrication (if they get hot, it is a different story). This is good for starting (no oil pressure). The biggest problem with them is as stated above, there are more wear parts than just the oil film. Thus changing the oil does not completely replace the wear items in the bearing. The journal bearing is truly awesome for longevity under high loads and high speeds.

The picture that is shown is from a small air-cooled rotary that has no pressurized lubrication system (mixed oil in the gas). This is why the roller (or needle) bearing is required.

They are. Needle bearings for cams and crank shafts are common place in high end circle track engines.

I only googled roller ratary in images and came across it. It was a link to ausrotary.com.

The reason they didnt have one for the S.B.C or any other piston motor was because they couldnt hold oil pressure because they were a two piece design. They have them now in high end sports cars like the {bugati} i geuss is how its said? I think this needle bearing design would increase response and horsepower do to less friction. Its like hydraulic cam vs roller cam. If there was a way to machine these bearings for the 13b, would you have to mill down the e-shaft or bore the rotors and stationary gears?

What would make the needle bearing less reliable vs journal?
Thanks.

Needle cam bearing in a V8.


http://image.hotrod.com/f/9512434+w7...mage_large.jpg

That look very much like a rotor from Woelfe Engineering's Aixro rotary kart engine.
http://www.woelfle-engineering.com/

It's a 294cc single rotor engine that gets about 40hp. The housing is water cooled and the rotor and bearing are cooled by the air/fuel/oil mixture, like NoDOHC said.
Here's an illustration from K. Yamamoto's Rotary Engine book:
http://homepage.mac.com/jolocho/intakeCooled.gif

40 hp???? I think thaty would work well on my riding mower :reddevil:

It's inherent to the design...
Less parts = better reliability
This is why journal bearings are used in the most inaccessible locations.

Anyone who has lost a pilot bearing on their RX-7's knows what I mean...


-Ted