You're right but you can make it simpler than that by just removing the rear or front plate to replace apex seals. This way you won't have to buy all new outer coolant seals.

Only downside to this is, having a bitch of a time sealing the oil pan

 

This is crazy dumb. Why would you go through all the trouble to do a half a job, it just doesn't make any sense at all for any reason other than to save time. It isn't going to cost you considerably more to do the full rebuild than a half rebuild, if you are going to reuse the good apex seals and side seals. Flat out you are dealing with a rotary, and you don't want to do sloppy jobs, be cheap, or take chances, it will kick you in the *** later. Just take the whole block apart and speck out the good apex seals and just re-use them on that side only, speck your housings as well, replace all the apex seals from the failed rotor side. Also if an apex seal broke off their is a chance you may have grooved out the intermediate housing which would require you to disassemble the entire engine anyway.

Either way plan on paying at least $1000 or more even doing it yourself.

 

Have you had any experience doing this "half rebuild"? I doubt it.

I have......... and it's worked perfectly.

 

The main problem is the difference in compression between the rotors. If you already have lower than "new/rebuilt" compression on the good side, rebuilding only one rotor might still give you uneven compression (most likely out of Mazda's specs) if it's from apex seal damage/replacement. While the motor will run, it won't be ideal.

Plus, you do run the risk of releasing the torque on the coolant seals which have already been "squashed" once. They may not seal as well once the tension has been released.

Bottom line, if you are going to rebuld one rotor, just do it right and tear down the whole thing for inspection, cleaning and rebuilding.

 

Although it sounds good on paper, the "half ***" rebuild works. If all your replacing/damaged is an apex seal then compression stays the same.

It's been done many times with greats results 100%..... yet the people who haven't tried it, doubt it.

I would only do this with a low mileage motor.

 

Re-read the post. I didn't say it wouldn't work.

 

but you said that compression would be different/not work.

 

Just because you have done it doesn't make it right, nor does it mean every engine can be done with success. I have taken apart engines with low compression front rotors only to find more problems in the rear. (Bad rotor bearing, water coolant seals that were starting to leak, seals beyond spec, etc.) It's a stupid idea, period.

If you are going to pull apart a motor go through it and do the job right.

 

The compression will be different between the rotors if you have used seals in one section and new seals in the other (if it's not a new/rebuilt engine). That does "work" as the engine will run. From my original message since you seem to have a hard time reading:

That difference may or may not be within Mazda's spec depending on how long the "good side" had been running.


Having low 8's on one rotor and low 7's on the other isn't exactly "ideal".

 

Bottom line, all the builders are going to tell you NO, while all the "racers" are going to tell you YES, and lots of others who are neither are going to say whatever they feel like, because they dont know any better.

Yes, it can be done. No, it won't be ideal. No, it doesnt make financial sense.

The fact that you're asking this implies you are doing it yourself, since NO builder would do it for you. So all you'll need to buy is parts. When buying enough parts to rebuild one rotor, you get enough to do the other one, so the only thing you're *attempting* to save is your time. Which you will likely lose more of later when you have to redo the job later. IF you have 6 apex seals on hand but only want to use 2 or 3, why not just use the other 3 as well and have a full set replaced?

IT is possible to take just part of the engine apart and leave the rest clamped together, but you run about a 50% risk of a coolant seal leak after it's reassembled...that's just the fact of the matter. There's no use in trying it, just take the thing the rest of the way apart and do it all the right way.

BTW, saying that no damage was done to anything when the seal exited is very optimistic...you almost always (95% of the time) have scarring on both the rotor and rotorhousing when a piece of seal gets ejected. Light scratches on rotors can be filed out and are fine, and VERY light scratches on rotorhousings are SOMETIMES reuseable as-is, but more often than not you have to replace at least one or both of those parts. See www.rotaryresurrection.com ---> tech ---> internal engine damage