Can rotor housing orings from a 13B or 12A be used on a 10A. 1970 - 1975 Are all intermediate housings the same for 10A, 12A, 13B ??? Can a single distributor front housing from a 13B be used on a 10A?
Any info on pre 80s motors would be of interest. (mix and match for better performance or reliability.
Cheers DT
www.r100madness.50megs.com
r100@telus.net

 

nope 10a,12a,13b rotors and rotor housings are uniqe

 

I know the rotor housings and rotors from 10a, 12a, 13b are different in width, but the housings have the same Inner/outer "diameter" do they not???

If this is the case does anyone know where to find gaskets and o rings for the 10a motor?

 

sry i misread
yeah the intermediate houseings from 12a or pre 1985 13b should work fine

 

NO!!!!!!!!!!!!!!!!!!!! Oh, sorry. What I meant to say was pre '73 10A and 12A irons are interchangeable. Yes a '74 or later single distributor front cover can be used. It seems Mazda relocated one of the bolts. This means the front cover will need one hole threaded and a bolt inserted (10mm x 1.25 is a good choice). You'll know which one when you test-fit the front cover on your engine. Also, you should be able to use an RX-7 gasket kit for the water seals and other multi-use items, like the dowel pin O ring, which you'll need to purchase a few more of. Just figure out how many and what size to order, and you'll be good to go.

 

opps
hehe

 

I am building a 10A at the moment, using a single dizzy front cover... fill one hole in, drill one new one (to run an electronic distributor).

Mazda here have all the seals, gaskets etc for the job. Even found a place selling brand new rotor housings, end housings and some other gear.

Other upgrades include new 12A stationery gear, new 12A comp. oil pump, 2 piece apex seals and single side seal rotors.

Anyone else here messing around with 10a's?

 

you can also check www.mcmaster.com

 

You can delete one set of side seals on dual side seal rotors for less friction/wear on the side plates.

 

Most of the rotors I have tracked down are single side seal anyway... just worn around the corner seal, but there is a fix for that

 

And that fix would be....?

 

Oversized corner seals.

After some digging around I found a couple of live part numbers (two different sizes). There is a factory tool that some dealers have that re-size the corner seal groove to fit the new seals. The old twin dizzy stuff has the wide apex seal, so there is less support for the corner seal which seems to move around and wear the rotor. The later rotors with 3mm or 2mm apex seals provide much more support around the corner seal and don't suffer the same problem.

Check your rotors - if the stock corner seal has ANY movement from side to side, no matter how small... it will be a #@*&% to start. You will have poor cranking compression. 10A's are hard enough to start anyway with the 6mm bricks they use for apex seals (unless you can track the 2-piece ones down.

Mine is still in the build, but some more mod's being chucked at it... now using series 6 / 20B stationery gear as they are stronger for the really high RPM, and have the nice multi-window bearings. Just had to be machined down a little. Also going to give a direct fire ignition system a run - a coil for each plug will help fire it up.




How is yours coming along?? Any luck tracking down the parts??