Hi,

Can anybody tel me how I can see what year my rotary engine is from? I have a 13B engine and have no idea what configuration it is or year it is made in.

Thanks.

 

u should try posting pix of the motor. and if you knew what car it was pulled from would probaly help these guys be able to help you.-Erik

 

If you take a peek behind the waterpump or behind the oil filler neck (where it's barely visible), you should find a casting number for the irons. That will help. Do you have two round intake ports at each end of the engine for a total of 6, or one oval one at each end (4 total)?

 

Thanks for the response.
The number behind the waterpump is 512692. Is this the serial number of the engine and if so is there a list somewhere that I can check it against?
I have 1 oval port on each end and 2 in the middle.

 

Do you have oil injection ports just above your regular intake ports, but in the rotor housing? Do you have coolant ports to pass coolant from the rotor housing to the intake manifold? Are there fuel injector bosses in the center iron? Is the engine mount on the front cover (four level bosses for bolts near the bottom) or is it on the underside of the oil pan?

The number behind the waterpump is visible only with the waterpump off. It's on the vertical face. The same number, however, is cast (raised, not stamped) on the backside of the center iron, just below the oil fill. That's the casting number for your plates, and it kinda lives in the shadow of your rear housing, in that 1/8-in gap.

If you have pics, it would help immensely. Unfortunately, 12As are pretty consistent, but lots of 13Bs (mine included) are bastardized with non-matching 12A or 13B plates mated to 13B housings, or lots of part-swapping.

 

Let me think, 76 Esaft, 86 fly wheel, 12a end plates year un known, rotor houseings 84/85 13bs. rotors 86 N/A,

 

frankenmotor....

if you know what years the engine parts came from, that's it.

 

Sorry for my delay in submitting some pictures. Due to a breakdown of my camera I had to do this with a webcam. The engine is diassambled right now.
In answer to the questions:
I do not see any oil injection ports in the rotor housing;
Yes, there are coolent ports in the rotor housing;
There are two fuel injector ports in the middle iron;
The engine mount is on the front cover.
The casting numbers all show the number R5. The front iron though has R5 E on it, the middle iron R5 A and the back iron R5 D.

Greetings,

Martin

 

another way to get some sort of basis is the font of the "mazda" emblem on the top of each rotor housing, get a pic of that and we can tell you more

 

Here is a picture of the Mazda emblem.
Thanks very much for the replies.

 

You shouldn't have fuel injector bosses. The old logo, R5 stamping, and rust make it look like a non-nitrided set of irons, which could be 13B or 12A and pre-78. Your housings have the new Mazda text with no oil injection ports, so they're 86 or later.

 

Which also means your housings were from a turbo, not that it matters much. I love frankenstein rotary engines. He also said he had injector bungs on the intermediate housing, so its definitly 84+. If I were to take a guess, assuming the engine parts are all original, i would say 86-91 turbo 13b. Which means lower compression rotors, not the best for NA applications.

Edit: What about 12a turbo housings, i know its not as likely, but did they have injector bungs on the intermediate housing? I'm not sure about the nitriding issue though. It's news to me that Mazda didn't do this to all their irons, when did they start this?

 

Thank you all very much for the replies.
I start to be a bit confused by the specialised language (and since I am not a native more problems arise).
What are fuel injector bosses? I thought I knew what they were but clearly I don't. And, what are injector bungs or non-nitrided irons for that manner?
The problem is that I have this engine for a while now and it started pouring oil out of the tail pipe. Since I was not sure what year the engine was I could not buy any new seals. I never expected it to be such a mix of components.
How can I find out what seals I need to buy?

 

The old mazda logo on the center iron means that it was pre-injection, so it won't have fuel injection bosses or bungs. They're just holes that merge with the intake ports that you can slide an o-ringed injector into. There's no way to specifically date your engine, but we can help you if you're looking for manifolds and stuff later on. Any 12A and 13B will interchange into another car with minor modifications, so it's not really necessary to know all the specifics of your block.

Nitriding is a coating that Mazda started putting on irons to keep exterior corrosion and interior wear to a minimum. Irons are never painted from the factory, so pre-nitride old irons (including your R5 set) tend to rust if they're not kept pretty clear of standing water. If you resurface them during a rebuild, you'll likely dig through the coating, and most rebuilt engines have worn through it long ago. It's not a big deal, but it helps you figure out their age.

Your housings have to be pre-86 because the water seals won't work with the irons you have. Your rotors and e-shaft (crank) might be a newer design, but it shouldn't change anything. A rebuild kit for a 84-85 RX-7 GSL-SE would be the easiest set of gaskets and seals you could locate that would cover everything in your engine.

If you're looking for oil control rings (they're the round ones on each end of each rotor) which are likely the cause of your oily exhaust, they didn't change much at all from year to year, but I don't know what rotors you'd have.

Since you're rebuilding things, just keep note of where all your parts came from as you figure it out. If you need new housings (yours are pre-79 but may still be in good shape) look for GSL-SE housings that you can mate to old 13B irons or any 12A set. If you're set on rebuilding, just tear that bad boy open and see what you've got. Take a digital pic of everything you can and write down any markings on your parts. Are you using a single-dizzy front cover?

 

Excuse me again but what is a "single-dizzy front cover"?

 

Single distributor. 74 and up.

 

Yes, I do have a single distributor.