Frequently, when you overhaul an engine, the apex and side seals
   meet wear specification. You don't need to replace them.
   Frequently what happens is the engine sits around for a long time
   and the apex seals may jam in their slots from rust or just plain
   gunk from the mineral oil crap Mazda recommends to put in the engine.
   Then the engine loses compression and won't start. I have a near perfect
   engine that had this problem. The end housings had almost undetectable
   wear. One rotor housings was near perfect. The other had minor
   problems and
   would still run probably for hundreds of hours if lubed properly.
   The outside of the engine was covered in grease, dirt, corrosion and
    looked like it had been run for ten years. If you mix 2 cycle oil
   with the fuel and disable the apex oil metering pump you won't have
   this problem. I digress.

   Genuine Mazda laser heated and liquid nitrogen cooled apex seals are
   ten times better than any after  market seals but they are
   expensive. Some ceramic seals are the exception. Iannetti ceramic
   seals have a long very good track record.

   However you must put the stock seals back where they came from for
   best results.

   If you can't get a box that looks like a rotor face the second best
   thing is buy four plastic boxes from wherever.

   I am going to make it easy for you to label these
   boxes. Print one of the box-labels.jpg.
   Print four of the seal-labels.jpg

   Cut them up with scissors or a paper cutter and place them
   in the right compartments of four plastic boxes.

    Mark one of the apexes of the rotor as top
   with a center punch in a depression or go by the markings
   that are already on the face of the rotors near the apexes.

   You need to do this before you clean the rotors as once the seals
   are out
   and scattered it is two late.

    You now are home free.

   BTW this engine is extremely easy to over haul but you need to be
   organized
   and know a few tricks. Don't attempt it without a shop manual in
   front of you. You can download them for free from links on our web
   site. My EeePC is great for storing and displaying the the pdf files
   in the work shop as the battery life is six hours.  One of the
   tricks is getting the flywheel back on with the woodruff key in the
   right place. The key tends to get pushed back out of the slot by the
   flyweel. Clean up the slot and the key with solvent and super glue
   the key in the slot before attempting to replace the flywheel.

   Paul Lamar

Paul,
Speaking of woodruff keys, on the other end of the engine, he needs to
be very careful that the woodruff key is in place after reinstalling the
oil drive gear.  Check it with a piece of safety wire to verify that it
hasn't slipped out and got wedged between the gear and the pump.  Ed
Anderson had this happen and didn't catch it until he didn't get full
oil pressure on runup on a cold morning.  Turns out with the thicker oil
from the cold temps the gear started spinning on the oil pump shaft.  If
he had gone ahead and launched who knows what would have been the result.

Mark S.