Like the title says when I was pulling my intake manifold to replace the gasket I had this slot on my block that was covered my my manifold (didn't have a runner going to it) so it was just covered in carbon (but it was soft so I'm not certain it was actually carbon?). I tried to Google and look around the forum but since I didn't really know what it was called other than "Slot" as per the Mazdatrix site I couldn't find anything.

I DID find a picture but the forum post it went to was just talking about injectors. The gasket I ordered from Mazdatrix fit my car just fine but wouldn't that mean my engine was from a 74? I wish there was an easier way to find the year of a 13B block.

Mazdatrix part link: https://www.mazdatrix.com/c-2.htm (It was the 74-75 ALL 4port)

Picture of slot (not my car):

I really appreciate the help, I'm still trying to find what year this engine is.
-Ghooble

 

Could you circle the "slot"? I'm trying to figure out what you're referring t0.

 

would probably be easier for you to post a photo of your engine if you need help telling what you have.

it's an EGR port.

 

Sorry lol, I considered circling it but I thought people would get it. My fault!
I didn't post a picture of my personal engine because the intake manifold is all back on, it's not really a problem per-se but I didn't know what it did and wondered if it was supposed to be covered by my Intake manifold.

EGR port eh? So it's for Emissions and nothing else?

 

is it covered or not?

a photo might still be helpful. even if i can't identify what you have, someone else might be able to.

 

It IS covered, the second quote you had was more of a "I don't know if it's supposed to, but it is" kind of thing. The slot I circled in the pictures is the one I'm referencing.

 

It's the 'Port Air' passage. It has no effect on engine performance, only tailpipe emissions. The passage is open to the exhaust, so that is carbon buildup on the engine side of the gasket.

Unfortunately, all that tells you is that it's a pre-89 center iron.

 

Woo! ..

I really appreciate the help. I just wanted to make sure it wasn't another thing to add to the list of bad things the PO did to my car.

Gracias!

-Ghooble

 

... hate to say it, but I don't think that's right. my S5 and S6 engines have that port on their intermediate housings. my S4 engines do not. I will have to go out sometime later to check my S3, but my guess is that it does. and let's not get started on the possibilities of earlier engines because I don't know about the "original" housings, but if you throw the possibility of using a 12A intermediate in there, then ....

so basically the only thing that appears to be off the table so far is 1986-'88.

what car is the engine in? what script is the "MAZDA" written in? is the rotor housing smooth or does it have "waves" between the tension bolts? this is why I asked you for a photo. doesn't matter "too much" if the intake manifold is on because the intake manifold itself can be a clue.

 

OH! I thought you were asking for a picture of my Rotor housing because you wanted to see the slot, not help identify the year. Oh man I'm an idiot sometimes.

Here's the best pictures I could take for ya. If you have a spot that would be of help feel free to tell me

 

from the photos you posted, the best I can do is it seems to be an SE engine or at least something built with S3 rotor housings.

 

Duly noted. I appreciate it Diabolical

Now to continue my quest to figure this engine out!

-Ghooble

 

6 port?
injector ports in the intermediate?

 

I'm sorry, what do you mean? As far as I know it's a 4 port but then again I'm not sure how to tell the difference. Rotaries are a lot different than piston engines

 

1. when you had the intake off, do you remember how many ports are in each of the "end" housings?

2. are there ports for fuel injectors in the intermediate housing (look near where it meets the manifold)? like in the photo you posted above ....

 

^Good catch. My mistake. S4 NA's have the slot on top. Turbo S4, S5 and S6 turbo's have that slot on the bottom. So that makes the only oddball the 86-88 NA center iron. Seems to jive with your experience and the Mazdatrix gasket pictures.

 

I think it had 1 port (where the intake runner goes, correct?) in each end housing, 2 in the middle.

I don't believe so.

 

well, i'll say this and then just leave it alone. that's essentially all there is to tell the difference between 4 port and 6 port. you count the intake ports. so next time you have the manifold off, then you'll know for sure.

if your intermediate has injector ports and it turns out to be a 6 port, then you probably have an unmolested S3 (the SE engine).

if it has injector ports and it turns out to be a 4 port, then someone "built" a 4 port out of an SE engine.

if it doesn't have injector ports, then it's likely someone probably used a 12A side housings to "build" a replica old school 4 port. this is what I see as the likely scenario.

 

I'll probably take the manifold off in the future here when I'm working near the turbo so I'll keep this in mind. Thanks friends!

 

In basically repeating what Diabolical1 said before, I wanted to add my input as well:
From the pics you have given, I can say that you atleast have 84-85 GSL-SE rotor housings. The 2 vertical ridges above the trailing plug holes and the newer style Mazda logo are a give away. Seeing as there are no smooth areas above the trailing plugs or holes for the detonation sensors which are common on s4 and s5 rotor housings, this leaves you with either being GSL-SE housings or 74-78 housings. But, seeing as the MAZDA logo is newer and not the older style boxed in, as well as the casting looking different on one of the 2 bolt holes on top of each rotor housing, I feel pretty certain to say they are 84-85 rotor housings.
As for the irons, all I can see is the center iron. It has injector ports, so it's immediately '84 or later. The earlier blocks had no place for injectors. They were all carbureted. This also brings up the fact that all blocks up until 1985 had the grooves for the combustion and coolant o-rings on the rotor housings and not on the irons like all '86 and later blocks. Seeing as you cannot mismatch these, this leaves you with having an 84-85 GSL-SE center iron. Now, if your outside irons had 2 intake ports each, than you most likely have an intact GSL-SE block, but if they have 1 intake port each, then you must have 12A front and rear irons on a mostly intact GSL-SE block. You can then somewhat assume that the rotating assembly is stock too - as a best guess.
So, it's either a full gsl-se block, or a full gsl-se block with 12a front and rear irons put on.

 

as far as I know, the knock sensors started (at least with US cars) with the Series 5 cars. now I honestly don't know if it was both T2 and N/A or just the T2 because I've read conflicting information and the S5 N/A parts I own were bought as such ... parts - none of which were rotor housings. I've never owned an original S5 N/A engine, so I can't speak from experience. [as a matter of fact, if someone reads this and can provide some clarity, that would be awesome. thanks.] my REW has them as well, so I will assume that they continued until the end of the Rx-7 production.

however, I have a few S4 engines and have read the literature to support this, and the S4s did NOT come with knock sensors.

unless I missed something, he posted only 3 photos of his actual engine and none of them were taken at an angle to confirm this.