I ressurected my 85 12a rx7 after a 19 year slumber...ran very well for while...but now suddenly it started pouring oil into the front housing....still has good compression front and rear....also some coolant into the oil sump..(no oil in the coolant though)...stock engine never rebuilt with 104K miles....
I am in the process of rebuilding it...but would like some input into what new parts are needed, what parts can i reuse?...assuming my housings, irons, and rotors are reusuable....what rebuild kit do I need? this engine will strickly be street driven with a street port performed.

 

Hey Rusty - welcome!
AFAIK Mazda still sells the FB 12A gasket kits. I see them on ebay etc for about $125-145. Or try Pineappleracing.com, Atkins Rotary and Mazdatrix, or heck, just check with your local Mazda dealer.

This gives you all the soft bits like gaskets.
You will also want:
-new oil seals for the oil control rings that are on each side of the rotors,
-new springs under the apex seals,
-new apex seals maybe? you will need to examine the current ones, measure there thickness against the Service Manual's acceptable minimums.
-Also new corner seals.
-figure new water hoses all around too
-smart time to replace clutch bits too
Unless you have done this before, the $30 you spend on Mazdatrix' "Rebuild" DVD is solid gold! Its for the 13B but same procedure and a lot of good tips you will not pull from the dealer service books. Its actually a pretty straight-forward job, with few specialized tools needed. A lot of guys here have rebuilt these. No dumb questions, so step up when you have a prob.
Stu A
80GS
AZ

 

I have good luck with the 12A Felpro gasket set that Rock Auto sells. It is comprehensive as far as soft seals go so it has oil and water seals along with all the other gaskets. Would second new seal springs and would recommend getting the late model corner seal springs I have the Atkins rebuild video but I am sure the Mazdatrix version is just as good. Just get one because they make this easy.

You will want a way to keep track of the location of Apex and Side Seals when you disassemble the engine, I found some plastic parts boxes at the hardware store that allowed me to label compartments. For each rotor you need three compartments for apex seals/springs and 6 side seal compartments.

When reassembling the engine, make sure that you tighten the case bolts in order and in several sequences. The last engine I put together I tightened the bolts in 8 sequences up to the max torque value. Helps to have good torque wrench that is accurate at lower values.

 

Thanks Stu....This is tremendous help.. .i haven't yet pulled my keg apart...just trying to prepare first for measuring tools organizing parts cleaning equipment etc. What's your thoughts on 3mm apex seals?

 

Thanks for the info. ..do u mean stock corner seals or solid corner seals?....I'm looking to build max reliability for street with some racing (autocross and drag strip)...which apex and corner seals would be best?

 

This is like my worst nightmare right now. Sub'd for future updates!

 

Rusty - can't go wrong with the stock seals. Once you pull the keg apart, meaner them to see if they are in spec. Others may have diff ideas about non-mazda seals. Atkins Rotary sells THREE types, so maybe worth a conversation with them about diffs and benefits...

The old style WIRE corner springs have been updated with the new ones, both are still avai, but presume most folks use the newer style. I did.

Stu A
80GS
AZ

 

coolant in the oil is probably nothing more than a freeze plug. and as stu said, get a micrometer and measure all the seals(apex, corner, side) to see if they're still within spec. the service manual has this. if they are, they must go back in the same place in the same rotor they came out of. the stock oem replacement seals will be just fine for a completely stock rebuild as this is the route i went when i did mine way back in '98. it's still running strong with nearly 200k on it, and it sees wot quite often.