Buddy of mine just scored a 13b 4 port from an rx 3 or 4. was needing to know what had to be done to put into his 85 12a chassis? had some bellhousing extender thing with what looked like half a torque converter. came complete with a manual tranny and all. What flywheel counterweight setup? motor mounts line up? need as much info on this swap as possible, Thanks.

 

that engine would have come from an rx4 or repu as i have one from an rx4 in my 84. i think RB and mazdatrix sell the front mount for a 13b into 12a chassis, or the one he has can be modified to work. could also source the front mount from a gsl-se. i believe the stock rx4 flywheel is the heaviest of all flywheels for these engines. don't know about this bellhousing extender thing ur talking about, never heard of such. best thing would be to just get the light flywheel and counter weight for the early 13b. others will chime in on other flywheels u might can use to retain rotational balance. but other than the front mount, it's pretty much a straight drop in as it will bolt up to the 85 tranny. and if the 13b still has the points dist i suggest upgrading to the electronic one from the 12a. jeff20b comes to mind as one who has lots of experience on the flywheel issue.

 

Front mount for 12A and 13B cars are identical. The difference is in the crossmember that the engine mounts are attached to.

 

Rotor weights are identical in 74-85 13b engines, so IIRC you can use a -se flywheel/clutch. This will bolt right up in place of your 12a. Use your 12a tranny.

I have notched several front motor mounts in the past, and they hold up fine to use a 13b with a 12a crossmember, or you can buy/weld extended front mounts.

+1 on swapping to the electronic dizzy if you haven't already. The 12a and 13b dizzys have a slightly different advance curve, but either will work.

I have been running a -se rotating assy in early 4-port irons for several years now. and highly recommend large ports, a modded nikki, and header/exhaust


Isaac

 

I want to beef up my Tranny, I just need to buy the parts little by little.

 

thanx. just wasn't sure where the differences was concerning that.

 

thanks for the info. it is a 74 with the ribcase style tranny with a removable bell housing. should we change the counter wieght with the gslse or just the flywheel? you guys and gals are awsome!! regular einsteins!!

 

Is a blind plug installed?

 

i dont know what or where the blind plug should be.

 

You say this engine came with a torque convertor but also a clutch? It's a J-spec auto-stick sort of setup. Could have been fromt he Parkway 26 passenger bus or a delivery van. These torque convertors used engine oil as tranny fluid so when you remove it all you need to install a blind plug in the end of the e-shaft. I think you can still buy them from Mazdatrix. Or find yourself any I think '82 or older shaft and unscrew the blind plug. Might be '80 or older shafts. Make sure it's a rusty or damaged shaft.

It takes a 6, 7 or 8mm allen key/hex tool. Look in the back of your shaft for a long deep hole or a shallow hole with a hex. You don't want oil drenching your clutch as soon as you fire up the engine.

 

Wow Jeff, the depth of your knowledge never ceases to amaze me. How the hell did you leanr anything about Japanese delivery vans anyway?




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I aquired an engine from one so I needed more information. It possessed features in between US-spec 74-75 and 76-78 model years. Kind of like how the Cosmo 13B-RE and 20B engines are the missing link between S5 and S6 RX-7 engines. Information has a way of finding you when you need it.

 

thanks on the blind plug issue. will check that out. should we leave the stock couter weight or use se like the flywheel/clutch?

 

All stock flywheels have the counter weight built into them. You would only need the rear counterweight if you go to a lightweight flywheel. The pre-86 13B counterweights are fairly rare so it's worth something.

Could you post pics of this bell housing extender? Can't say I've ever seen one.

 

i will post those pics soon. i too had only heard of them until now.

 

i am tryin to get those pic for you guys. busted camera! i was wondering if i use a 13b se oilpan and pick up tube or what? thought someone said yes but cant find it now. i know rb has "special" 13b to 12a conversion oil pan. should we invest or go with something else?

 

The GSL-SE oil pan is correct. The special device RB sells that you're thinking of is a modified front mount bar that allows a 13B to fit in where a 12A originally was.

I'm removing the 13B from my '81 and selling all the 13B conversion parts very soon. If you can hold on, I'll have these available: GSL-SE oil pan + pickup tube, RB front mount bar brand new, RB road race header very low mileage, radiator fan shroud lightly modified to clear the fan, and lastly an aftermarket aluminum flywheel + clutch disc and pressure plate used but lots of life left. PM me for first dibs. These will go up for sale as a kit in the FS section when they're all removed and ready to sell. Probably later this month or early next.

 

Something RB fails to mention about the driver's side motor mount shell is that it has to be trimmed, by you, when you use their front mount bar. Otherwise the shell edge smashes against the front cover. This is the best pic I have of a trimmed shell.

 

here's those pics of the 4 port 13b auto-stick tranny. first pic shows the tranny, bell housing, torque converter/flywheel, and counter weight. second pic shows the torque converter thing. looks like torque/flywheel combo i see on automatics! the third and fourth show how it was assembled. the forth also shows the slave cylinder tube, the metal tube, which was mounted on the bottom of tranny. if anyone is interested in buying these antiques let me know.

 

interesting!

 

very weird! ive driven the porsche version, it wasn't that cool....

 

finally have the motor installed. we are using the stock carb. not sure of what it is but it is kinda complicated. just using it for now till something else is ordwered. noticed when it sits water seeps into the combustion chamber and out the header. not good. we also noticed the oil metering pump not workin. sure that is because of wrong pickup tube. have been premixin the gas for now. will have some pics up soon. sounds pretty mean as of now. cant wait to hear it when all is good!