people arround here in Puerto Rico are machining the stock bearings to deep groove and the .0005 extra clearence for high reving engines, what are the specifications of the RB rotor bearings??? im going to try this at my school tomorow se how they end up you guys think it will work???

what about making the stock main barings multy window?

 

Yeah, people do that around here as well.

I didn't make my rotor bearing grooves deeper, but did use the FD rotor bearings. I did window my stat. gear bearings and clearanced everything.

If you are into doing other oil system mods you can check my thread

https://www.rx7club.com/rotary-car-performance-77/pics-blue-tiis-engine-build-new-type-primary-port-489429/

Bearing mods
E-shaft journal mod
E-shaft rotor jet mod
E-shaft thermal pellet mod
Oil pump cavity port
Oil pump pick-up mod
Oil pump outlet relocation
Loop line mod
Etc.

 

thanx

 

.200 thousand I usually have the stock rotor bearings machined into deep groove.. thats 200 hundred thousand deeper..

 

.002 deeper in the groove ??? does this take the chrome away?

can this be done in a lathe or does it have to be a grinder?

 

I would assume you could use a dremel if you were very careful. Hmm this is giving me an idea also and something I may do when I break down my NA S5 engine when it hits 10k. I have a rotor with a bad bearing I may just experiment on.

 

I'm pretty sure the stock rotor bearing is much less than .200" thick. I think they are like 3mm thick. Are you machining through them?

I've thought of machining a groove in the rotor, under the bearing like the stat gears and then windowing the bearing. But I've never followed through with it. I think the MFR bearing has a .080" deep groove.

I machined my bearing groove deeper with it in the rotor in a lathe using a three jaw chuck. Protected the rotor with small pieces of brass flat stock.

 

crap you guys confused me waht should i machine out of the bearings on the groove and the clearencing????

is it .080 or .200

 

i'd like to see a writeup on this in the future. i tried to do it myself with a Demel about 2 years ago. it didn't turn out so well. i'd try it again, but i'd prefer not to do it blindly.

 

From Racing Beat Technical Manual and Parts catalog

"For high performance street and racing use , the best rotor bearings we offer ar MFR rotor bearings with a deep oil groove and additional clearance (approximately .0005" extra). While stock bearings can be grooved deeper and polished to obtain additional clearance, the MFR bearings are still a better choice. The MFR groove is approximately .070" deep to provide an improved reservoir of oil around the bearing."

"Up to 8,500 RPM, .003" +/- .0005" eccentric shaft-to-rotor bearing clearance is acceptable. Beyond 8,500 RPM, clearance should be .004" +/- .00025". Clearance can be adjusted by polishing the inside of the rotor bearings with 400 grit or 600 grit we-or-dry sandpaper strips which are spun with a high speed motor such as an air powered die grinder."

Now, Racing Beat specializes in racing where some classes allow NA rotaries, but very few turbo rotaries so there is much less info in their literature about building to turbo specs, but I did get the impression that high HP turbo rotaries will also cause the E-shaft flex and high oiling requirements below 8,500 RPM that NA motors require above 8,500 RPM.

Also note that even 600 grit wet dry paper lubricated w/ WD 40 spun in a die grinder (at high enough speed to self center the shaft) will QUICKLY remove the bearing babbit material. Practice finding the self centering speed and material removal rate on a JUNK bearing first. I use 600 and 1,000 grit paper.

It is also useful to remove more material from the outer edges of the bearing than the center as the center has more oil to prevent seizing and the e-shaft flex will affect clearance more at the ends- this is a matter of judgement and experience. If you tear down a rebuild (that didn't have oil system failure) and the outer edges of the bearings are worn shiny- more clearance is needed.

 

thanx im going to clearence them an add .002 in the groove