Rear main seal, rear stationary gear o-ring

scotty305 · 11-14-2010, 01:34 PM

Hi all,

I recently replaced the original (88k miles) 13B-REW from my 1994 RX-7 with a used 13B-REW from a 1996-1998 Japanese RX-7. I got the longblock from an importer, the compression tested good (I measured over 110psi on all 3 chambers of each rotor) although the engine appears that it may have sat for a while, possibly outdoors.

I've installed the engine in the car and it starts and runs well, good oil pressure, doesn't smoke, idles smooth, pulls hard, etc. The only problem I've encountered is an oil leak from the flywheel side of the transmission bellhousing. From what I gather there are two likely culprits: the rear main seal and the rear stationary gear o-ring.

One friend (who spent a couple years working at a rotary specialty shop) advised me that it's possible to replace the rear stationary gear o-ring with the engine still in the car, by removing the transmission & flywheel and then prying the rear stationary gear out carefully. I tried this on the car's original engine (which is sitting on a pallet and hasn't been disassembled yet), but so far I haven't gotten the stationary gear to budge. In the Mazdatrix rebuild DVD, the rear stationary gear is removed by hitting it with a soft mallet from the front, not by prying from the rear.

I've already ordered both replacement parts (o-ring and rear main seal) because they're cheap. The question is should I attempt to replace the stationary gear o-ring or just do the rear main seal and hope that will cure the leak?

11-14-2010, 01:34 PM	#1
scotty305 Rotary Fan in Training Join Date: Mar 2008 Location: Culver City, CA Posts: 84 Rep Power: 18	Rear main seal, rear stationary gear o-ring Hi all, I recently replaced the original (88k miles) 13B-REW from my 1994 RX-7 with a used 13B-REW from a 1996-1998 Japanese RX-7. I got the longblock from an importer, the compression tested good (I measured over 110psi on all 3 chambers of each rotor) although the engine appears that it may have sat for a while, possibly outdoors. I've installed the engine in the car and it starts and runs well, good oil pressure, doesn't smoke, idles smooth, pulls hard, etc. The only problem I've encountered is an oil leak from the flywheel side of the transmission bellhousing. From what I gather there are two likely culprits: the rear main seal and the rear stationary gear o-ring. One friend (who spent a couple years working at a rotary specialty shop) advised me that it's possible to replace the rear stationary gear o-ring with the engine still in the car, by removing the transmission & flywheel and then prying the rear stationary gear out carefully. I tried this on the car's original engine (which is sitting on a pallet and hasn't been disassembled yet), but so far I haven't gotten the stationary gear to budge. In the Mazdatrix rebuild DVD, the rear stationary gear is removed by hitting it with a soft mallet from the front, not by prying from the rear. I've already ordered both replacement parts (o-ring and rear main seal) because they're cheap. The question is should I attempt to replace the stationary gear o-ring or just do the rear main seal and hope that will cure the leak?