Rotary Engines.
 

Hello all..
I'm considering buying my first RX-7.
I've been around ur standard engine for a while
But before I get in over my head. As far as
Rebuilding and trouble shooting are the rotary
Engines as complicated as everyone says??
Any input would be much welcomed

There's nothing really more complicated about a rotary than any piston engine. Actually the engine itself is quite a bit more simple. The only slight weirdness about the rotary is that the EFI system has staged injection, and there is both a leading and trailing ignition. Really though, it's an engine like any other.

"Everyone" says that it's complicated because, well, frankly they are just ignorant parrots repeating what they've heard others say.

Here's a few videos of a teardown and rebuild:

These videos will help you in the process of rebuild a 13B or 12A engine. While they deal with an older 13B from an RX-5 Cosmo, the engine internals are basically the same for any 12A or 13B. The only real difference is that on engines newer than '85, the coolant o-rings are in the irons instead of the housings as shown in this video.

The first video is engine removal. While it is an RX-5 Cosmo, an car that few will ever see let alone work on, the process will give you the general idea of an engine removal. Steps are similar for most rotary vehicles, it's the details that differ.


The next video is engine disassembly and some cleaning. This is an old carbureted 13B so the accessories bolted to the engine are different than newer engines. However the process of externally disassembling any rotary is about the same. Covered here is also flywheel removal (same for any rotary) and engine parts cleaning.


Cleaning of all engine parts continues in this video. Provided here are examples of how this is accomplished with a minimum of tools and supplies. It's a lot of labor to clean old parts until they are looking new again. At the same time, parts should be inspected.


Finally, here is the engine assembly. This video includes clearancing side seals, assembling all the seals onto the rotor, then assembling all the parts into a 13B short block.

Lets just say, rotary motor is so easy to work on, that a 16 year old kid wont have a problem rebuilding one with all the proper tools, and proper manual.

How about maintaining it?

If you change your oil like you should check your fluids and do.proper maintainence including preventive maintenance you shouldn't have any problems

Rx7s don't even have valves or a timing belt, virtually eliminates blowing an engine from jumped timing/broken timing belt.

Don't let your rotary overheat or go low on oil, those are the killers.

if you can change oil in a car you can maintain a rotary engine.
The only problem with the car is the age of it.Once you get the stuff that deteriorates out of the way and back to new the car is a keeper.
WTF beat me by 30 seconds!!!!/..sorry WTH..lol!

Thanks for those video.... I learned a lot from them...

Well you still got me beat by 10,000+ posts lol

@Aaron Cake

Watched through your rebuild vids, you make it look way easy. I'm guessing you make it look a little easier than it is though huh? Still, I've been bitten by the tinkering bug now.

Well everyone has a starting point, .practice makes perfect combined with intelligence devotion and common.sense in mechanics.

Im going to rebuild my first rotary shortly in the future.

those were some great videos, i plan on rebuilding my NA engine before the end of the year.

watching those videos helped me understand a lot about rotaries, saving this page for future reference.

There's really nothing more to maintain than any other vehicle of the era. But keep in mind that these are old cars, and by todays standards require a hell of a lot more maintenance. However it's just normal stuff: fluids, belts, hoses, a TPS adjustment now and again, plugs, etc. The only real difference with a rotary is that when you check your oil at every fill up (which you do on every vehicle, right? :) ) you will find that oil will be needed every 1K or so because some is naturally consumed to lubricate the rotor seals.

It's true, that assembly was not my first tap dance by far. There was some editing (actually a bit segment was cut out that showed me scrambling for another water o-ring because the one that came in the kit was cracked...now I keep 2 spares in the shop at all times) out of minor issues. Really though, if everything is laid out and a person is familiar with the procedure (keep that FSM/Haynes handy for torque specs and info on how to orient the oil o-ring springs) then anyone mechanically talented can do the job.

Nice thread for noobs like me, thanks!

rotary engines are powered by black magic, i sacrifice a goat just before i assemble one.

Not sure about the others but I think the 3rd gen. Stickys talk about reliability mods. Most revole around cooling.
That should hint at what to focus on as far as maintanence.

rotary engines are simple once you learn how they work and rebuilding is easy if you have a good manual (mentioned before) or a person that knows what they are doing! Once you crack one open and you drive one you will be hooked lol !

OK, question. Suppose you want to rebuild your engine (diy), keeping it stock, about how much are the various, lubricants, and other supplies gonna run? A ballpark figure here would be helpful.

The videos were a great help for all of us novices...Thanks

IIRC HYLOMAR BLUE for installing the coolant seals was ~ $15 -$20 for a tube. HONDABOND, THE RIGHT STUFF or other quality gasket maker is another $20 or so.
A small tub of vaseline $4. Maybe some EASYOFF oven cleaner for removing carbon $5.
If you're someone experienced enough for a DIY rebuild, you should already know how much assembly lube, high-temp and low-temp anti-seize, two or three cans of aerosol WD-40, a small tube of thread-lock and a box of latex gloves cost.
Of course figure about 3 gallons of new coolant/distilled water and the break-in period will also require a couple of extra oil changes with filter.

So THAT'S your secret! ;)

i believe he means the necessity to rebuild an engine once it's open. as i always say, the 3 piece OEM seals need to go in the garbage. doing it cheap will wind up costing more in the end with a chunked rotor and housing because the 3 piece seals are below minimum spec even at 75k miles and at 150k are about to fall out of the rotor and get eaten.

minimum budget is about $600 which includes apex seal set, springs, soft seals, main shaft seals, sealant, lubricants, oil filter, cleaner and some cleaning supplies.

if you have unlimited access to parts then sure, a soft seal kit reseal will probably last a few years.

actually it's mainly because i generally assemble engines after lunch. :)

Sorry Colonel, when you said "lubricants and other supplies" I thought that's all you were asking about.

And Karack, can you even still buy 3 pc OEM? I thought they weren't even available. Are old 3 pc stock still showing up that someone had lying around?

mazda doesn't sell the 3 piece seals any more, 2 piece only.

Calling it about a grand if depending on price variances and what tools you might need to pick up for special purposes and whatnot. Sound right?


Edit: Man... you eat a whole goat for lunch every day? That's impressive...

Great thread learned alot