6 port 12A
01-29-09 | 02:44 PM
#26
Thread Starter
Lapping = Fapping
iTrader: (13)
Joined: Aug 2001
Posts: 15,725
Likes: 83
From: Near Seattle
I'd like to update and add a correction. I now think that RE-SI and GSL-SE end plates are the same and only the intermediate plate is different for each engine. The RE-SI being small ported and the GSL-SE with the larger NO size ports.
01-29-09 | 10:20 PM
#27
Junior Member
Joined: Jan 2009
Posts: 11
Likes: 0
From: Great Falls, MT
Ok, but how do they provide back pressure to turn the intake slides then? And why did mazda put holes in the rotor housing? Couldn't they have just cast the housing without holes and still provide back pressure? 
09-19-09 | 03:38 PM
#29
Thread Starter
Lapping = Fapping
iTrader: (13)
Joined: Aug 2001
Posts: 15,725
Likes: 83
From: Near Seattle
I'm in the middle of tearing down my 6 port 12A. What I can tell you is it appears the intake manifold bolt pattern is the same as a GSL-SE (this means I can swap some GSL-SE or RE-SI plates but I'll double check). The intake ports are comically and tragically small. Far narrower than those posted above by bumpstart. I'll shoot some pics eventually. The front counterweight appears to be the '83-'85 style (as I predicted) so whoever put a 30 pound '79-'80 flywheel on mine was an idiot. I got as far as removing the front plate, housing and rotor. Gotta get back to work and take out the rear rotor in a bit...
I hope the rotor bearings are still good. Stat bearings are a dime a dozen, if worn out by the wrong flywheel, but I'd like to reuse the rotating assembly if I can. I would like to use the set of 12AT rotor housings that have matching exhaust pressure to 6 port actuator holes; the only problem is they lack coolant ports as they were undrilled for the 12AT, but the 6 port 12A was drilled like any carbed 12A. This could mean the intake manifold will get hot. What should I do? I don't want to risk machining/cutting holes in the coolant ports because I lack the tools/bits needed. Do I need to worry about the heat potential?
Lastly I'd like to rebuild the 6 port 12A and drop it in my '81 S and experience it for a while.
The goal is a perfect in-between type of setup that will range somewhere between a big streetport 13B and the original tragically small ports of the stock 6 port 12A. I've built plenty 4 port motors with various porting, intakes etc. Now I'd like to try something a little different. Who'd like to follow the build in this thread?
I hope the rotor bearings are still good. Stat bearings are a dime a dozen, if worn out by the wrong flywheel, but I'd like to reuse the rotating assembly if I can. I would like to use the set of 12AT rotor housings that have matching exhaust pressure to 6 port actuator holes; the only problem is they lack coolant ports as they were undrilled for the 12AT, but the 6 port 12A was drilled like any carbed 12A. This could mean the intake manifold will get hot. What should I do? I don't want to risk machining/cutting holes in the coolant ports because I lack the tools/bits needed. Do I need to worry about the heat potential?
Lastly I'd like to rebuild the 6 port 12A and drop it in my '81 S and experience it for a while.
The goal is a perfect in-between type of setup that will range somewhere between a big streetport 13B and the original tragically small ports of the stock 6 port 12A. I've built plenty 4 port motors with various porting, intakes etc. Now I'd like to try something a little different. Who'd like to follow the build in this thread?
