sen2two

im not really sure on how to choose the correct clearence rotor bearing. anyone wanna do a little "how to" write up real fast. ive done this on piston but not rotary. so i have a general idea. thanks ahead of time.

Lynn E. Hanover

It depends on what you intend to do with the assembled engine. Stock is about .0039" Call it .004"



Good for anything up to hard racing lasting long enough to foam the oil. Want to go a little harder? .0045"



for weekends on the dyno and autocross, and amature drag racing. Use at least 100 PSI for oil pressure.



Track days, with all of the shifts at the rev limit. .005" Just sand off the overlay and polish the copper.



For operation well above the rev limit. Hone out the rotor bore another .0005" Bolt the bearing into the rotor.



Clearance to .0055" Lighten the rotors. Clearance the rotors. Along the combustion chamber and the sides along the corner seals. Balance the rotating assembly. 115 PSI or more for oil pressure. Oil pan baffle. Bigger oil cooler. Synthetic 40 Wt oil. Start looking for an external oil pump. Good to over 10,000 RPM. A small group of drag racers go much higher, but they don't share the data. !2As can go way higher. Lighter rotors and stiffer crank. Chamfer the front end of the rear main bearing. Rotor life may be short.



Look inside to check on things often.



Lynn E. Hanover

sen2two

damn... thanks



but how exactly do i find the clearence i need?



measure the outside of the e shaft. than inside of the rotor bearing. and subtract those to get a clearence???



i wanna push about 600WHP and not going past 8k on my REW.



i see three different ones on mazda trix.

Lynn E. Hanover

Start with the biggest bearing. It is barely bigger than stock but it is bigger so go there first. If you could find some of the old, real race bearings that are .0005" over stock, they were made from tubing, intsead of flat stock with a puzzle lock. They have a harder overlay as well, so I would try them first.



If you don't detonate the engine, the bearings will hold up to pretty much anything you can think of, at lower revs. Tear it down often and look for shiny bearings and little flakes of silver along the edges of the bearings

where the overly is moving away from the high stress areas. Between passes or weekends or whatever it is you do,.........cut open the filter and look for silver and copper. An overloaded bearing dies slowly, and gives you a warning in the filter. An overstressed bearing may fail in a few revolutions. Detonation may fail a bearing the instant it happens, or a week later. So it is often hard to detect the actual event. Constant over loading moves off metal, shines up the bearing in the overloaded area, and eventually opens up more clearance. So idle oil pressure starts to go down over time. Also the added clearance may limit max oil pressure, rather than the rear relief valve. So instead of pegging at the usual 115 pounds with the revs up,

it may only get 105 or so. So there is your notice to cut open the filter for a look see.



Use and internal mike or a snap gage (cheaper) and an external mike to measure shaft diameter and bore diameter, in 8 places each. Subtract the largest shaft diameter from the smallest bore diameter to get the clearance number.



If you build one and it cannot hold the relief pressure with the revs up, its time for more oil pump. An external pressure pump or the whole dry sump system.



Test the rear relief valve for the exact cracking pressure you are looking for. Or use an early valve and shim it up yourself.



Lynn E. Hanover

sen2two

THANKS AGAIN!



im off now to harbor freight to get an external and internal mike. been meaning to get some mikes anyway...

sen2two

maybe you can help me with this Lynn...?



i want to use the rx8 e-shaft and stationay gears. but stay with my REW rotors. what size rotor bearings would you recomend then?



and i also want to have the rotors beveled. am i going to be dropping off too much weight on my rotating assembly? is there even sufficient power gains to justify doing this?

Lynn E. Hanover

I have no knowledge in this area. I have not had the new engine apart yet.



Lynn E. Hanover

j9fd3s

part numbers for the rotor bearings are the same between the 93-02 rx7 and the rx8