Lynn E. Hanover

Well how nice of you to say..........



I should have added that real racing bearings used to be made of a seamless steel tube. No longer the case. The bearing is just a strip of sheet stock rolled into a tube with a puzzel lock feature crimped together. The area of the puzzel lock is not allways smooth, so they grind down the ID in this area a bit, so it does not touch the crank. As you would imagine, this forms a bit of a path for high pressure oil to escape in both directions, reducing oil pressure and adding to the already excess oil foaming problem.



The tube may not be round while in the box. It becomes truly round only when pressed into the bore of the gear. So it is important that the pressing operation go along perfectly. In my case I chamfer the start edge of the bore just slightly to be sure no material will be scraped off the OD of the bearing and end up trapped between the bearing and the bore wall.



I was making grooved gears and windowed bearings before Mazda. Probably most builders were as well. A builder (whos name escapes me) was loosing front rotor bearings. So he rigged up a rotating seal to fit over the crank nose. Drilled through the seal plug and the bolt to get an oil pressure reading at the crank shaft center. OOPS. 13 PSI, at full blast on the dyno. Now at the time most folks were running an extra oil line to the front stationary gear, and jacking up the oil pressure to 85 or 90 PSI. And that seemed to work out. But this guy knew why the failures were happening. Trying to force oil into the end of a fast moving tube against the centrifugal load was just not as easy as it should have been. That and the oil squirting holes for rotor cooling make this a difficult problem. There is no resistance at all to oil flowing out of the squirter holes, but considerable resistance to flow to the front rotor bearing. Once the oil column length to the rotor bearing exceeds the length of the column going into the crank, you start to gain a bit of pressure, but it isn't much. So we put scoops in the crank leading to the oil gallery in. And wiping trays out of the gallerys leaving the crank. VW is a big believer in this, so I do it as well.



I also use a 180 Weber main jet in the squirter hole bottoms, and 100 PSI oil pressure. I do not know if Mazda reduced the squirter hole diameter when they went to 110 PSI or not. But that put more oil through the front rotor bearing, and the waste oil from the bearing cools the rotor as well as oil that is just squirted in and does nothing for the bearing. Remember cooler oil means lower charge temperature and that means more charge entering the chamber on each cycle and that means more power, and less chance of detonation.



Lynn E. Hanover



The taller idiot is me.

fc3sboy1

the oil jets in the rx8 e shaft have been changed , same oiling set up on 2 motors, REW oil presure regulators rx8 gears both 6 port E Production engines both have the crank plug in the front of the motor. one engine uses the RX8 MSP e-shaft the other an s5 eshaft. the s5 motor with 20w50 oil cold presure is 120 hot 100psi the rx8 eshaft motor same oil cold is 125 and hot 115 psi.



now granted there could be a diferance in the gauges but that is a large number on almost identical engines with differnt eshafts.



anyways Lynn I always like the way you word things so people can understand. great to have a fella like yourself in the rota comunity.



randy

j9fd3s

the FD and RX8 high power (and cosmo) all use the same bearing. the low power rx8 uses the 74-91 parts...

JustJeff

I appreciate all the useful info

fc3sboy1

this is an incorrect statement. the last 3 13bRE cosmos i tore down and they are the only 3 i have build all used a single hole none set screw bearing. and the RX8MSP bearings are not the same as the 13bREW rear gear. the sizes are differnt between the REW and MSP as far as clearance goes and part numbers.