I'm in the midst of rebuilding a Cosmo 13B RE (2-rotor) and I thought I'd post info and pictures as I go through the process. It's going into a 95 RX7. My original intentions were to just install this engine in "as is" condition. I was worried that the engine wouldn't be 100% healthy and the thought of tearing the motor back out to rebuild it didn't appeal to me. So I ripped her open. Turns out she was just fine. Really really good actually. Oh well.



I'm waiting for a few items to arrive (rebuild kit) so I'll post images of the internals, specifically the intake and exhaust ports. Here's the exhaust port as seen from the inside of the housing.

Here's the exhaust from the turbo side. The sleeves are very restrictive. If you've ever wondered why a three rotor is so quiet, this is why. The simple solution is to pull the exhaust sleeve pins and replace the Cosmo sleeves with FC or FD sleeves. Don't forget to port them!

here's the primary intake inlet. About the same size as an FD port. There's room to hog these puppies out, but I'm not planning on anything too crazy. Check out the machining/casting mismatch....that can't help power too much!

Here's the primary inlets, intake manifold side. Again, there's plenty of casting to be removed to clean them up.

Here's the secondaries. Much larger than the FD's. I had a chance to lay a porting template over the top of the Cosmo ports and the template (monster street port) wasn't too much bigger...sort of scary. I plan on going as far as I can with the secondaries.

Secondary, from the intake manifold side. You can almost hear your own echo https://www.nopistons.com/forums/pub...#>/BURNOUT.gif

And here's what I did today while I wait for my rebuild kit, porting kit, etc....I started at about 9 this morning and finished about 5:30 this evening. Polished the UIM, throttle body, and repolished my GReddy elbow and Cusco strut tower bar. Forgot to polish the IC piping! Once the engine is removed, I'll polish the LIM, front cover and anything else I have time to polish. I'm almost finished polishing the housings as well. I'll have pics soon!

Cool,whats involved in putting the 13B RE in place of the 13b REW?

Pretty much nothing...apparently, even though the Cosmo motor mounts bolt on in a different location, the rear housing has all the bolts for the FD's engine mounts. Everything else is identical. Has the same primary injector bung, etc...some things that need to be swapped out are the stationary gears (trying to figure out which one), front cover (FD's bolts right on) and the FD's intake manifold system. You can use the Cosmo's intake manifold, and if you have the time/resources, I definitely would do that. You'll need to make a 1" spacer to fit between the throttle body and the GReddy elbow so everything lines up. The Cosmo secondaries are top feed. You could mod the stock fuel rail and run 1600's. I already had 1300's and didn't want the extra expense and setup time.

The cosmo intake has much bigger runners. here's a look at the mouth of the intake. That U slot on the bottom is exposed when using the FD's throttle body. One could simply weld it shut but a spacer would be better as it'll allow everything else to line up. I'd do it out of phenolic material. Cheap, easy to cut and shape.

Here's a comparison of the FD and Cosmo intake manifold. You can see the difference in length. The Cosmo runners are all almost identical in size and all are bigger than even the FD's primary runner.

Here's a closeup comparison of the FD secondary runer (LIM) versus the Cosmo secondary runner (LIM). Here's hoping that these ports work well with the monster turbo I'm running!

nice work man. Great pics!

very nice

https://www.nopistons.com/forums/pub...IR#>/bigok.gif keep up the good work, I'm soaking it all in for when I have to crack open my 13B-RE also!

LOL, 20/20 hindsight, I probably would have been fine just sliding this engine in. That's not nearly as much fun as rebuilding though! Quite a bit cheaper however https://www.nopistons.com/forums/pub...IR#>/smile.png

Ok, I've learned that it's a good idea to replace the stationary gears with those out of an FD. They accept the better bearings and deliver more oil to the E-shaft. They're hardened too I believe. The Cosmo style stationary gears are identical to the TII's.

ah ok, the 20b cosmo gears are used in the fd then



mike

you really really should take the time and use the cosmo upper and lower manifold, You'll just need to mod your throttle cable and rework a little bid of intercooler piping and splice in the throttle postition connector.. If your missing anything like the elbow or throttle body I can probably get them for you.. I would run a 20B throttle body on there if I were you. it has the same Idle control valve as the fd on it so your harness will plug right in and control the idle. I just happen to have one for sell https://www.nopistons.com/forums/pub...R#>/tongue.png and it is all so 2mm bigger than the FD to boot..

nice pics! all together the cosmo engine is better than the tt.

Cosmo RE better than the REW? Yes and no...Yes in that the primary and especially the secondary ports are MUCH larger than the FD's. Now, whether or not the ANGLE of the ports is better is up to debate, but they're very similar. FD's have several important updates, mainly revolving around the oil system. The FD stationary gears have nine-window bearings, meaning they have nine holes where oil gets through to lube the bearings. The Cosmo has three stock. Additionally (related), the Cosmo stationary gears are not hardened. If you didnt' know, the bearings are IN the stationary gears. Simple solution? Switch to FD gears. The oil pressure regulator in the FD has a higher pressure than the Cosmo (13B RE).



On the exhaust side, the Cosmo has extremely restrictive exhaust sleeves. The actual exhaust port opening is identical to the FD but the FD sleeve is much larger. Why not just port the Cosmo sleeve? Because it's HOLLOW. Ask me how I know :-) Swap them out for the TII or FD sleeves. They're identical.



Lastly, you'll need custom engine mounts. As of yet, I have no definitive source for them but I'm working on it. Dragon, any help here from the land of the rising sun?



Dragon, you're probably right...I did port the FD lower intake manifold substantially so it shouldn't be too bad...for the time being, I need to get the car up and running. I "may" experiment with the Cosmo intake system but it'll require a custom fuel rail (available from K2RD.com btw) and a lot of other items. The cosmo intake, while having larger runners, uses a plenium-style intake while the FD's is a more modern thinking pulse wave tuned type. I've talked to a few drag racers using them on 9,8, second cars and apparently it produces more torque. Might be good for the street. I'll try and post some images here soon. Motor is going together over the next few days. Damn, watching MotoGP on Speed TV...memorial to Daijiro Kato who died recently racing at Sugo in Japan. Very sad. The things we do for speed.

lol, I answed your question on the OTHER forum.. https://www.nopistons.com/forums/pub...IR#>/wacko.png last night..

of how to mount the 13B RE in the FD go see..



http://www.rx7club.com/forum/showthread.ph...threadid=181093



https://www.nopistons.com/forums/pub...DIR#>/cool.png

Ok, three months later, I finally have an update! The good news is the motor is in the car using custom made motor mounts. More good news, these mounts will be available throuch Compact Car Performance in Naples, Florida. They're fairly simple, made out of cast iron and triangulated on the passenger's side (and we may triangulate them on the driver's side too). It bolts to the engine in three locations, two on the rear plate (just like stock cosmos) and one on the intermediate plate. I'm the guinea pig but they look strong enough considering the factory mounts are aluminum. Everything is being checked over and it should be up and running tonight (Saturday) and ready to go by Tuesday morning. Then comes the long, arduous 1K mile break in proceedure https://www.nopistons.com/forums/pub...>/rolleyes.gif before I can slap it on a dyno and start tuning fuel. How about a few pics? Here's an "overall" of both sides at once. Engine sits in the same location, same height, etc...

Another pic of the passenger's side, looking at it from the front of the car. you can't see where it extends forward and connects to the intermediate plate. Oil pan gets in the way.

Damn, that image came out a bit bigger than I thought it would https://www.nopistons.com/forums/pub...#>/biggrin.png Another shot from the rear, passenger's side

So...along with everything mentioned above, you'll need to use the new motormounts and you'll also have to use the stock FD oil pan. Because the motor mount bolts go through the oil pan, you'll have to weld those holes shut. Additionally, you'll use the FD front cover, pully, and oil pickup. Sounds like a lot of work and it was for me and Compact Car but most of it revolves around swapping parts during rebuilding. One could just throw it in there unmodified internally. See the how to port sticky post for pics of the finished ports. Oh forgot to mention...the lower portion of the motor mount (flexible, damper part) is the FD's lower. Just reuse them. Estimated cost for the motor mounts will be somewhere around $200-$250.

That seemed to work out pretty well Michel.

I am curious what made you decide to do a 13bre?

Also what are the benifits of such a swap?



Really good job with the documentaion, gee one would think that you are pro journalist or something https://www.nopistons.com/forums/pub...DIR#>/wink.png

LOL, originally the reason was the stock larger ports. I was just planning on throwing the engine in, unopened, unmolested, as I was told the short block would bolt right in. It was a short term answer until I could gather everything for the three rotor swap I have planned.



The shop convinced me to open her up however, and once that happened there was no turning back. Then I saw the "how to port your engine" series and the rest is history :-)



The real value of using the Cosmo, especially the plates, is the port size. Even if you maxed out the FD ports, they wouldn't be as large as Cosmo ports maxed out. Since I have quite a large turbo, the larger secondaries will really come into play judging by what others have experienced with the same turbo. That and the initial cost of an engine is about $500 to $600 cheaper, sometimes more. everything except the stationary gears and exhaust sleeves are identical to the REW FD engine (shaft, rotors, etc...).

I am curious what kind of work went into changing out the sleeves?

Are they pushed out with a press like bearings??

The sleeves are not too hard to remove...you'll need to read Ito's post on that topic...essentially they're held in on either side by small pins which need to be pulled. Use a TIG welder and feed a bit of the line into the pin itself (it's hollow) and blast it with electricity. Then place another bead on top of the first bead and then one more...pull with pliers and it'll come right out. Might take an attempt or two. The sleeves slide right out after the pins are removed. Again, you can use FD or FC sleeves. So if you have a few trashed housings lying around, pull those exhaust sleeves!

Good work Michel.....that should be one hell of a beast when its finished. Giving me ideas now that im looking at doing a rebuild for my FC since i blew it a couple weeks ago. A 20b FC......has a nice ring to it....... https://www.nopistons.com/forums/pub...IR#>/bigok.gif

LOL, yeah it's a bit easier to do the three rotor in an FC. I say go for it! Then again it's your patience and pocket book. https://www.nopistons.com/forums/pub...IR#>/smile.png

looks good michel. i might have to come done and check it out. Harrison and i are starting to take harrisons car apart in preperation for his single turbo swap. hes getting a 60-1 but hasnt decided on whether to get a 1.00 or a .84 with a tangetal divided. anyways.... ia msure he will tell you all about it.



later



john

13B REW on the left and 13B RE Cosmo on the right



Is that the right order? https://www.nopistons.com/forums/pub...1047683561.gif

Actually both. Whenever it's "bigger", it's the RE, not the REW. :-)

Michel

Sweet stuff you have done to the FD , rx7tt95. i was wonder if the new motor mounts you use could be used on a RHD FD. Also any more updates about your beast ? like times or dyno pulls



vids would be sweet hehe https://www.nopistons.com/forums/pub...#>/biggrin.png



You take care of that girl as you rip another ******* for those hundus... https://www.nopistons.com/forums/pub...IR#>/boink.gif

So is it possible to use the FD motor mounts? Or is it required to make custom ones like you did?

can the new mounts made by Compact Car Performance be used on a LHD FD?

Any updates to this thread...real good information...This thread was a learning experience... https://www.nopistons.com/forums/pub...#>/biggrin.png

You could just use a FD rear plate, then the stock FD motor mounts hole would be there. You would just have to port it to match the cosmo.