Better to watch something like this first! Waking up an '85 12A that sat for 17 years. "Compression" is important, but don't compare with anything not a rotary! Turning an original, functional 12a over by hand is easier than turning over a lawn mower. Mine turned over so easy last fall, I picked up 2xcores over the winter expecting to rebuild one of them. 280,000 kms on this one, and it runs! I used transmission fluid, instead of MMO. Added some through sparkplug holes, and turned it over a few times by hand every day for a week. From totally breathless to "some" compression in that time. EDIT ADD ON: 3:1 shaft to rotor spin ratio. When spinning for compression be sure to spin 3+ full turns, and listen for compression coughs 2x per single rotation (two rotors 180deg apart) One failure on a rotor, and it'll lack compression for 2 of 3 faces per cycle. Don't panic. When using "running" as a test...they can "run" on a single rotor. 1 and 1/3 rotor is rougher in idle.

@tox5303

4 жыл бұрын

Want to sell it 👀

@ca444

4 жыл бұрын

@@tox5303 Hello from Canada

I have an 81 RX-7 with a 12a engine that has 120k original miles on it that I am currently planning to do a rebuild on and that is of course what lead me to find your youtube channel. You seem quite knowledgeable on rotary engines and your presentation was pleasant and easy to follow. Hopefully you can point me in the right direction to resolve a problem. There was a problem which caused me to park the car.. One evening after a short drive, I shut the engine off and immediately heard a PLINK sound (best description is that it sounded like a nut/bolt hitting the bottom of a metal can). I assumed at the time that it may have been something within the oil pan. From that point on, the engine will not turn a full rotation, it will only turn somewhere between 270* to just shy of 360* and backwards the same. Because of it not turning a full rotation, I did examine flywheel bolts to assure none were missing or backed out & wedged, so I was able to eliminate that as being the problem. Based upon my description of the problem, is there something you have experience with or that you have knowledge of that you can you suggest might be the likely cause? I have owned the car since 1984, it has been garaged due to the failure since 1989. Yep, I'm that guy who won't sell because I plan to fix it one day, except that one day has finally arrived and I am now ready to begin. lol

Awesome video man! I'm looking into buying a rotary for my project and this info will help a lot.

Great video mate. Really wish you where around. I have a 85 fb and two 12a engines that I want to rebuild and it running.

Dude great info. I have an SA with what I was told is a 74 13b In it that has say for 10 years. Sounds like I'll be doing a rebuild.

@RADPotential

4 жыл бұрын

Awesome man! That should help you get the right parts and understand what you're working with

Man am I lucky to have found you! I just bought an 83 gsl with a 12a that sat for 8 years since it ran. Apexi cat back exhaust and some other mods lead me to believe that someone has had the motor apart. I'm hoping I get lucky and that it won't need much to run.

@RADPotential

3 жыл бұрын

Awesome man!!! Search the archives for videos on how to do things on the car. Drop a comment with any questions. I love to help out!!

@lakeshorerides

3 жыл бұрын

@@RADPotential absolutely, I'm stoked to be able to learn about and work on a rotary!

Great video! I just picked up a 74 Repu that's sat for 15 years after the previous owner overheated it. Can't get it to turn over yet but I'll keep trying. Even though it'll need to come apart I just want that win haha are the old school engines like the Repu has any good for a turbo setup?

Thank you

Would you please do a video or provide a link to describe information about the interchangeability of 13B motors? I have an "85 GSL-SE and it appears to be the original motor, though I cannot tell, but doubt it. It has 203K miles and has been restored to like new condition inside and out with some interior upgrades and Tanaka seats. I know it has been rebuilt and is very strong and has been a reliable engine. I've put about 600 miles on it since I had it and it starts reliably (cold or hot), shows no smoke on start up, keeps all its coolant and is addicting to drive. (5 speed). But I'd like to know what options are available if I need a rebuild as parts are getting really scarce or unavailable. I saw the vid about the GSLSE rotor differences. I also have everything in stock shape with the exception of having a RB header and RB dual exhaust system. All the air controls are in place. So what is interchangeable if you want to rebuild a GSLSE motor?

I’m in New Zealand. Have a ppre built (pulse performance race engineering) 13b full cut Bridgeport. Have noticed lately a sweet coolant smell coming from it. Not using any tho. And no smoke. Motor has done about 10 000kms. Was built 7 years ago. Also noticed a kind of jelly inside the oil filler neck and under the oil cap. This I’m guessing is just internal moisture that isn’t evaporating due to not getting the engine hott enough. What’s your thoughts

My 1982 Rx7 GS needs rear brake drum replace. Get the new brake drums, the brake shoes, the brake cylinders BUT can't find the drum brake hardware kit (shoe springs, shoe retainers, shoe clips). Called Mazdatrix, Racing Bear, Summit Racing, Rockauto, they all run out of stock. Can I find a complete kit used? Or any hardware kit from another car compatible?

Question, what do i remove to do a vacuum delete on 1979 12A SA22C engine

Looking at a couple of rx7-8’s what do you charge to rebuild an engine???

hi from east tn i subbed be nice if you were me ye ole neighbor.lol.. i bought a 1980 i think i forget exactly 12a its got a cannon intake and japan made side draft runs but needs re seal i guess seems to smoke thanks

Thanks for the into! Im looking to buy a FB 13B for 300$CAD, it does need a rebuild, its fine, i'll learn to do it, but is there any way for me to know if the housing is mangled with out taking it apart?

@RADPotential

2 жыл бұрын

If you can get a bore scope, a camera to look inside engines. You can look down the carb, but otherwise you qill need to take it apart.

Hey thought of a question for this old video. What about spinning the engine with an impact driver or drill on the front bolt to compression test? Or does that run the risk of running end play.

@RADPotential

3 жыл бұрын

You would need a big drill to get ot going. Much like a starter work. And impact I wouldnt to full ugga dugga on that bolt

@ScottJ175

3 жыл бұрын

@@RADPotential Thanks. Just ordered a RCT 5.2 and am eager to try it on something when it gets here. Maybe I'll do the RX-8 instead although I just changed plugs about 300 miles ago.

Is buying a cheap 13b and replacing the apex seals and other seals with newer and nicer seals and also cleaning it worth doing to flip it. Would it be worth the time and money to flip it and make money off of it?

@RADPotential

3 жыл бұрын

In this day and age probabaly. Just finding one that is usable then building credibility in your skills as a builder

I keep hearing that in order to use Rx8 rotors in a peripheral exhaust engine, the apex seal grooves need to be milled deeper. Do you happen to know the reasoning behind this?

@RADPotential

4 жыл бұрын

I do not believe so, you would just run an rx8 apex seal and spring as that fits the rotors.

@rematty69

4 жыл бұрын

They mill the apex seal grooves in rx8 rotas because they are a lot swallower than the fc or fd motors and ware out alot faster so you get the milled out so you have a larger range of apex seals to choose from . N/A s4 rotas are the best for building a tuff n/a motor rx8 rotas are realy out of balance from factory

How many splines does the rx8 tranny have?... can I still use a factory 85 Fb driveshaft and rear differential

@RADPotential

4 жыл бұрын

Rx8 and turbo2 trans share the same splines and length. You will need a turbo2 to first gen driveshaft. Iirc mazdatrix sells one.

What do you personally use for premix

@RADPotential

4 жыл бұрын

Whichever I can find for a reasonable price. Usually Lucas oil from the parts store. Gallon jugs.

hi i have a 88 T2 engine and it spins with out ,making any noise. spins with no effort at all good or junk?

@RADPotential

3 жыл бұрын

I woildnt call it junk but just low compression. Could have stuck apex seals or stuck side seals. You can try soaking it in marvel mystery oil, or just look in the exhaust ports and see if the seals are free. Probabaly has some usable parts in it for sure

A 13b is a 13b right? Like I'm trying to find parts for a 74 rx4 that has sat for 30 years and there's very little info on these. A 13b from a first gen rx7 should be mostly the same correct?

@RADPotential

2 жыл бұрын

Nope there are differences in ports, and housings etc, you can make a later model engine work, but it will require a different carb setup and swap the oil pan. Flywheel needs to match the series of rotors.

@meatstiick

2 жыл бұрын

@@RADPotential I guess i need to keep looking to find rx4 parts and not just what i thought was the easy rx7 direction. Or maybe it will just startup fine after 30 years!

Do you want to sale any of your motors looking for a 12a or 13b

I just got a 1982 gsl from a one owner the car had a bad coil I didn’t know weather a was getting a good deal or not couldn’t work on it with him 👀 me so I gave him 34$ plus 300$ for the tow 100 miles away car is 99 % stock just the original radio is gone 😏🤣🤣🤣🤣🙉 am going 🍌

Wish I knew where I could buy an engine at a normal price

@RADPotential

3 жыл бұрын

Can't find them anymore. Makes me sad I passed on a few in the past

@kevinaweseom2866

3 жыл бұрын

@@RADPotential my local salvage yard has a 12a (I think) that's been sitting with a manual trans behind it, the oil cap was off and the hood was up, ive been debating on going and pulling it with the trans and tear it down to see if I could learn about it. Maybe save it. I'm new to this so no one can tell me if $350 for the motor is a bad deal

@RADPotential

3 жыл бұрын

If there are any good parts you could recoup that money, 350 for the engine and trans together isn't a bad deal necessarily but it is a gamble hoping there are some usable parts in it

Who can I get to rebuild my 160 hp 13b

@RADPotential

3 жыл бұрын

Where are you located? Phalanx performance in STL

You got a email can send me? Got my first rotary in a box torn down. Sweet project vehicle just dont know where to start with the engine and what's useable. Can take plenty of pictures.

@RADPotential

3 жыл бұрын

RAD potential @ gmail.com or instagram. RADPOTENTIAL

How much knowledge will a person need to rebuild a 12a.

@RADPotential

2 жыл бұрын

Not much man!!! Depending on what wrong with it. These engines are super simple!!! I am working on a comprehensive rebuild video to upload soon!!!

😂 bought 2 12a and both were bad

@RADPotential

4 жыл бұрын

Feel your pain brother!

@stock8080

3 жыл бұрын

I want to rebuild my 1980 Mazda 12 a engine the engine runs but I want to rebuild it completely it’s been sitting for about two years? I’m from Florida I cannot tell where you from where can I get a rebuild in Florida?

@fantomtsi

3 жыл бұрын

@@stock8080 there’s a bunch of good rotary mechanics in central Florida area.