4 port or 6 port
 

I bought what I was told was a 1976 13B 4 port motor. It runs good, but a guy looked at it and said it was not a 4 port, he knows by looking at the intake. Can he tell by looking at the intake bolted to the motor? Can someone tell me how I could tell? Thanks.

Yes, he can tell.

Is there an intercooler bolted to the top of the throttle body?
Yes = 4 port
No = 6 port

Also, there were no 13B's in 76. Did you mean 86?

they did make 4 ports
and yes 4 ports came without a turbo
74-75 13B 4 port
76-83 13B 4 port

It's a 76 13B. It's not turbocharged.

If it's a 76 13b, then it's a 4 port.

what I meant to say in my last post is that it's a 13b, but Im just going on what I was told by who I bought the motor from that it's a 76 4 port. Is there a year stamped on the block?

I meant FC's. Oooops.

No, there's not a year on the block, but if it's a 76, then the Mazda logo on the rotor housings will look like the one that I attached below.

If it really is a 76 motor, you'll get better answers in the "other rotary" section since that was way before the 2nd gens.

https://www.rx7club.com/members/rotaryhaven-13311/

if that doesnt work search for jerryperez. hes a buddy of mine and he has a couple of old 4 port 13bs. you can crank about 250hp out of them N/A. if it runs and you can drop it in an fc or an fb id do it. good luck man.

I put the motor in my fc with a webber carb and header. Runs strong but still needs some better tuning. Is there a place in Hamton/Newport News area where RX7 meet? Thanks for the help.

How did you mount it in your FC? On a 76 center housing, there is no provision for FC motor mounts. Did you adapt a front mount?

no. everything lined up.

there was just 1 mount on either side.

Then it's definitely not a 76 engine.

So all 76 4 port motors have a center motor mount. Then my motor must be a 6-port. Correct?

None of the 76 engines had the mounts on the center iron. All of the early US spec rotaries through 85 were mounted by a bracket on the front cover. Your engine could be an 86-91 4 port TII engine or an 86-91 6 port n/a engine.

I'm using an 88 n/a intake manifold. It bolted right up. Does that indicate that it is a 6 port motor.

Maybe...did the ports on the manifold look the same as the ports on the engine? An 86-91 TII engine and an 86-91 N/A engine have the same intake BOLT pattern but there are 2 intake ports on each n/a end plate and only one intake port on the TII end plates.

I'm not 100% but I think they looked the same when I bolted it up. I'd hate to go pulling it back off. You ever heard of anybody blocking off ports to make a 4 port?
Would that even make sense?

Look on the top of your front iron just behind the CAS. If it's a turbo 4 port block, there will be a threaded hole that a banjo bolt goes into for the turbo oil feed line. On an N/A 6 port engine, there is a brass plug in it from the factory.

I'll take a look. Thanks. What is the CAS?

CAS=crank angle sensor. I forgot that you were running a carb on your FC, so you probably are using a distributor. So, look on top of the front iron behind your distributor.

do you have camera to snap a shot of the motor? without photos, there will be a lot of speculation. not to add to the confusion, but someone could have easily sold you a GSL-SE motor under false (or ignorant) pretenses.

He said he bolted into his FC using the stock FC mounts with no problems. You cannot do that with a GSL-SE engine.