Just picked up an old skool 76 cosmo 13b
 

Like it says I picked an original 76-77 (not sure) cosmo 13b motor complete w/ carb and tranny. Its has the "MAZDA" on the housings w/ blue paint. It has 48k original miles and from the sound of the compressions after rotating and a few things here and there it does seem like a legit low mileage motor. I plan on porting it "1/2 bridge" and throwing my Edelbrock on there to put in my 83 gsl by June. Hopefully I wont run into any suprises when I crack her open. :icon_tup: Will post a few pics as soon as I can.

A member and I tried to rescue one out of the yards here in Ca. The only thing missing was the steering wheel. The white leather upholstery was still in great shape. The chrome on the bumpers was like new. The only dent it had was on the lower driverside under the door. She was just begging to be saved but the cards did not play out. :-(

I know alot of people are looking for housings that say Mazda on them. You might be able to part out that engine if you don't care what it says and make some cash on them. Probably enough for you to buy another block and some other go fast parts!

MAZDA = '74-'75 RX-4 and REPU. It's not a Cosmo engine. I would know. I have a '76 with original engine and it has the later mazDa logo.

You may be right. That may explain the huge alternator. However I'm going to try to match it up to my 83 gsl 5spd, but regardless of what year motor it is, I'm gonna open her up port it and replace anything worn out. Cant seem to find much info on the "MAZDA" housings. :wallbash:

I have to disagree. ALL pre-RX-7 housings are capitalized and italics lettering. In addition, the 76+ center plate (no matter if its RX-4 or the RX-5 Cosmo) didnt come with the rectangular smog port below center plate.


http://img.photobucket.com/albums/v3...Picture168.jpg

I could believe that a Cosmo would have the later blocky 80s Mazda script becuase that script came out in the late 70s. My Cosmo parts book has the blocky mazda logo on it and all the Cosmos I've seen have blocky script emblems not Italicized ones.

I could be wrong on the letterings but as I said, a true 76+ 13-B blocks (RX-4 and Cosmo) came with no rectangular port as you can see in the above intake manifold. If I find time, I will take pix of my extra cosmo block.

I just took off the intake and it does have the rectangular port. Hmmm, it has "automobiles" just above the "MAZDA" logo on the housings and and 13b stamped above that. I cant find my damn camera! Super strong compression and the clutch assembly looks real nice. Off to find that camera!

then its not a Cosmo but a regular 13-B.

i was waiting for u to say junk it wanko

LOL. "JUNK IT"

I have a feeling that our homeboy Latin picked up an old R5.

Nah, wacky calls everthing "junks". :)

Hey, if the rotor housings say "Automobiles" it might be a cool J-spec engine. I have a set that came from either a delivery van or the AP bus (or whatever it was called). If I had to narrow the year down, it would probably be a '75 engine. Remember their home market got stuff before we did. The exhaust port timing is that of a US-spec GSL-SE where it opens later than US-spec old 13Bs and closes at T2 spec. :)

My Cosmo was built in late '75 as a '76 model and it has the mazDa logo. It also lacks the ACV port below the intermediate intake ports. It has had a reversed runner manifold like in Wacky's picture.

....and whats the deal w/ an R5? Please tell me you junk collector.lol :icon_tup:

I'll try to get some pictures too.

Latin270, how tall were the intermediate ports? That will narrow it down a lot.

R5 has been around since the '76 Cosmo and RX-4. Only the REPU kept the earlier casting 3B plates and MAZDA logo until the end of their run in '77. It was easier for Mazda to get past emissions restrictions with the '74 spec ports of the 3B plate because it was in a truck. Only the cars got the smaller '76-'85 spec ports.

R5 ran from the '75 or '76 model year until the nitrided ones in the '80s with a high volume oil pump and other later upgrades. Then Mazda shifted their attention to the 6 port RE-EGI (GSL-SE) engines.

http://img.photobucket.com/albums/v3...r/DSC04584.jpg
http://img.photobucket.com/albums/v3...r/DSC04588.jpg


VS. pre-84

http://img.photobucket.com/albums/v3...r/DSC04585.jpg
http://img.photobucket.com/albums/v3...r/DSC04586.jpg

The J-spec rotor housings with "Automobiles". GSL-SE exhaust port timing. :)
https://www.rx7club.com/forum/attach...d=235334&stc=1

My '76 Cosmo engine.
https://www.rx7club.com/forum/attach...d=235335&stc=1

Worst case scenerio I could use these housing w/ 12a irons, right?

yes but 79-83 are preferred.

You might need to. Have you seen how small the van/bus intermediate ports are? Yeesh!

Here is a series of pictures I posted a few months ago while trying to figure out the best combination of parts to build three nice engines. Enjoy.

All the short port plates I have easy access to. Note the delivery van/bus plate in the middle.
https://www.rx7club.com/forum/attach...d=228468&stc=1

All three have the exact same port timing! (the flash messed with the R5's port)
https://www.rx7club.com/forum/attach...d=228469&stc=1

Some moron built an REPU engine with the stupid NO plate so I had to correct it. :D
https://www.rx7club.com/forum/attach...d=228470&stc=1

Comparing NO ports with standard '76-'85 12A ports. The picture speaks for itself.
https://www.rx7club.com/forum/attach...d=228471&stc=1

A couple of Y plates with the NO and R5. Notice the offset casting?
https://www.rx7club.com/forum/attach...d=228472&stc=1

Now a comparison of manifolds.
https://www.rx7club.com/forum/attach...d=228476&stc=1

I modified the back of the Cosmo manifold so it would fit my MG. I also cut channels in the top. We'll see how well they work when I get it running in a week or two.
https://www.rx7club.com/forum/attach...d=228477&stc=1

Nice collection there. :icon_tup:

Almost starting to think its a REPU 13b because it has a sensor type thing on top of the center iron.

Egr?

Heres some pics.