how do people clearance bearings for rotary's.how much oil clearance should we run(rotor,main) in high horsepower apps.(500whp+).whats the max./min we can safely run?

thanx pro's,
aaron

 

Racing Beat says .003 to .0035 for rotor bearings under 8,500rpm and .004 to .0045 for rotor bearings above from what I recall. But they also say anytime rotor weight is high, power level is high or rpms are high to give more clearance than stock spec.

They recommend clearancing them by flapping them w/ 400 and 600 grit wet dry sandpaper in a die grinder.

 

wow ive never heard of anyone recomending taking sandpaper to a bearing.does anyone knw the part numbers and sizes for the different size bearings?

 

all the bearing size and part numbers can be found on the racing beat site.

Question, if your using three window bearings does the cleareance still need to be bigger than stock? What if your running higher oil pressure than stock. soud the bearings till be flapped.

Also what is the flapped technique anyways?

 

The Mazda competition bearings come with extra clearance built in. ~.0015" extra clearance I believe. One should still check clearances and adjust for application.

The silver babbit coating is quite thin ~.001" so you may end up w/ copper bearing after clearancing.

The flap method is to put a split mandrel in a die grinder and put in a strip of sandpaper/ emery cloth and spin it at high rpm so it self centers.

Flapping can be used for clearancing bearings, finishing intake port runners and even honing intake manifolds.

 

From what I understand the copper bearings do not harm the e-shaft. Have you heard different?