13b housing question.
 

hey guys just a few odd question.

i rember seeing a post on the other site of some one machining a 13b housing to work on a 12a motor. right now my sa is in my car tent and i plan to rebuild the motor and restore the car and do more mods till my rx8 is paid off (few years at least.. a part of me wants to convert it to a 13b,and part of me wants to stay 12a and be different. if i go 13b i mite just do a TII swap. if i stay 12a i mite go cadmen, turbo pport ect.

any ways my question is encase i need new housings, what 13b housing would i need to buy and have machined to the right width. is it just a matter of fly cutting each side x amount and iam done or would i need to have a cnc program made up and have some thing machine on each side. yeah yeah i know what your thinking iam nuts but like i said i saw this done in a thread from the evil site. the only thing is i cant find that thread.


the reason i ask is i can get them machined for free if its just a matter of flycutting each side. if it needs cnc work a few 30 racks of beer will pay my old boss off lol.

Well, you need a coolant seal groove if you're using pre-'86 irons.

any pre-1985 13B housing is 12a iron compatible. IE the cooling passages line up. But for amount of work and more importantly, money, i can't see machining a 13b housing down to a 12a housing (either pre or post 85 13B). I would have to verify but i dont believe the cooling passages in the later 13b would line up with 12a irons. Plus you would have to machine a cooling seal groove

ok ok so for this to work turn a 13b houseing in to a 12a i would have to have to do alot of cad work ect ect. thanks.
what i got confused about was the whole coolant seal groove. couldn't think of the term before. i thought 86 and older had them in the irons so all i had to do was fly cut the housings. but i guess i had that wrong. i can do the mahcine work my self so id just need to show up at my buddys place on a weekend. if they needed cnc work he wanted just beer. but i didnt want to take a chance the came out bad.

the main reason i asked this is i got two great deals offered to me in the last few weeks. one was a set of racing beat 13b pport housing, and a new in the box TII housing. i figured if it wasnt to much work i could rebuild my 12a for less then a 13bTII swap. but i guess ill just go 13b TII swap down the road.

I remember seeing that thread and I believe he used 13b housings shaved 5mm on each side, which removes the chrome flaking on worn housings, with TII plates and 12a rotors and eshaft.

He also machined a new coolant seal groove into the housings.

Why not use something like a 6 port 12A intake manifold? Then you wouldn't need to machine coolant seal grooves in the rotor housings because a set of FC side plates could be used. Of course how often does one run across a 6 port 12A intake manifold? They're as rare as 4 rotors.

heck i have only seen a picture of the carb air cleaner, on a 4 port 12a.

TII plates have a coolant seal groove.

Ah, right. I thought you said 12A plates. But still, that's what I thought he used. He had access to a CNC shop.

aren't they somewhat common in the overseas market since the 6port 12a was the engine they used starting in like what, 82 til 84.