lost cause

Where in the US could I get a hold of a 13B 4-port?? Are they pretty rare?? Would it bolt in directly to an '80 Rex or would I have to modify the car as if I was putting in a 6-port??

gonzz

I just got done installing a 13B 4 port in my right hand drive 80. Need 12A front cover/Special front eng brace .. that's about it.. and new clutch/pressure plate.. Going to crank mine up in the A.M. and need new header also..

Any more questions just PM me..

Later, Gonzz

Project84

all the 84-85 GSL-SE's had 4 port 13B's

ioTus

iTrader: (5)

no, those were 6 port werent they? Thats what i've been told!!!! I think thats why everything is special for

13b EXCEPT GSL-SE (which is some other special 13b application) when looking at 1st gen parts (from Racing Beat or something)

Project84

I have 2 '87 13B 6 ports in my garage. All the 1st Gen SE's were 4 ports. Also, the first gen 13B's have the water seals in the rotor housing. The 2nd gens have the water seals in the end plates and center plates. The rotor housings are smooth. I just did a search on it 2 days ago cause someone tried to tell me I had a SE motor when I pulled it out of a 87GXL.

ioTus

iTrader: (5)

Arent these 6 ports???

http://www.racingbeat.com/resultset....rtNumber=16734

Also, my thread i was referring to:

https://www.rx7club.com/forum/showth...hreadid=111220

From reading on Racing beat, you dont need the water seal "O" rigns unless you have the 12a 4 port, cause the 13b 6 port ( 84-85 models) dont have it....

Now i'm confused...

MIKE-P-28

iTrader: (1)

13b 4 ports are easy to fine. They are available in any turbo model LOL Now if you want an old 'working' 74-78 13b 4 port good luck ...

DJ Rotor

GSL-SE's were six-port only. I understand you can make your own four-port if you like, by using 13b rotor housings and 12a ends and intermediate housing.

J

Directfreak

iTrader: (2)

Yes. The GSL-SE's are SIX-PORT Engines.

All 1984 and newer N/A 13B engines are six ports.
All 1983 and Older 13B Engines are 4 ports
All Turbo Rotary engines are 4 ports.

Read the article below - 6 PORT LAYOUT..

1st7heaven

All 84-85 SEs from the factory are 13b 6-ports!!!!!!!!!!!!!!!!!!!!

You can build a 13b 4port pretty easly.....here was one of mine.

Jaye

Mazdatrix sells a complete, bolt-in (as far as I can tell) 4 port 13B...made with all new parts, no less.

1st7heaven

I meant to say that all you have to do on the front engine bracket is bend it.....thats all I ever do on my conversions. It takes a big sledge hammer and a big vise!!

ioTus

iTrader: (5)

So what is the advantage of going back to 4 port??? I thought that 6 was better, ya know, bigger numbers prove it!

DJ Rotor

have you read the info on mazdatrix site re: porting - if not, do! six-ports = much harder to port and lower gains

Project84

I know the 6-ports are harder to port with minimal gains. I'm working on removing the diffuser from the exhaust port. The engine is already apart, and so I'm going to do it cause a small gain is a gain none the less.

rx7passion

13b 4port? get a turbo 2 motor and take all the crap off you want, blamo instant 4 port motor. sure the compression is a little bit lower but i doubt you'd really notice it that much and you can always put a different set of rotors in there to bump it back up

peejay

A true "13B 4-port" was available in RX-4s, RX-5 "Cosmo"s, and REPUs, 1974-1978. (In the US anyway...)

The GSL-SE engine is a 6-port. It's the same rotating assembly as the '74-78 engine, with "6-port" end housings (probably the same as the 12A 6-ports used in Japan starting in '81) and a center housing with smaller ports and fuel injector bungs (probably the same as the one used in the Japan-only '83-85 12A Turbo).

The '74-78 13Bs used the exact same side housings as the same year 12As. You can easily make a "4-port 13B" using 12A side plates with GSL-SE rotating assembly (again, same as '74-78) and rotor housings, as well as the niggly bits like oil pan, tension bolts, and dowel pins. Because of that, it's easier to start with a GSL-SE engine than it is to start with a 12A.

But basically, a "4-port 13B" is just a 20mm longer 12A.

The '86-up engines really are quite different from the '74-85 engines. Yes, a Turbo engine is a 4-port but it's not really the same as a "4-port 13B".

Project84

All those damn ports! They should all come stock with peripheral ports! That way you get massive A/F mixture and more bang for the buck.

peejay

If you want factory peripheral ports, find yourself an NSU

MIKE-P-28

iTrader: (1)

Yelp, and you have to crop one of the corners. I didnt like how it looked so I bought the RB mount. But if look at it really close its an OLD 12A mount that the mounts piece on the sides were cut off, one corner was cropped (drivers side) and TIG'ed back on

Jeff20B

iTrader: (13)

peejay, didn't the GSL-SE have 9.4:1 rotors?

peejay

Yep! You got me on that. Weight's the same, though... must've been what I was thinking of

moremazda

iTrader: (4)

Now confirm this rumor

series 4,5 and 6 rotors can be placed inside of early 13b housings, BUT early 13b rotors CAN NOT be placed inside of the later 13b rotor housings. I have heard there are clearance issuses with later of this statement. What are those clearance issuses?

peejay

The shape of the rotor housing was altered.

I can't verify that, unfortunately. But FORTUNATELY, very soon I will have my hands on a S4 6-port, and amongst the dissecting it and playing in its vital organs, one of the things I plan to do is do some mix-n-match with an early rotor housing and an early rotor (12A pieces but they're the same shape as early 13B) and see just WHAT the differences are.

Note that I *have* heard of people putting GSL-SE rotors in T2 engines, for the 3mm seals with no machining hassles. (WHY would you want to downgrade to 3mm seal? But anyway...) As well as the common swap of S5 rotors in early 13B.

So, we shall SEE! And there will be pictures. And it will be good.

lost cause

Now for the other question, would I have to to any other major mods to get that set up to work??