12a rebuilding, anyone done this???
 

I have been hearing more negative things about these rotaries.... well just in the cost depo..... has anyone done a rebuild themselves? Or has any1 gotten a video with a how to on rebuilding, or does any1 have a link with a how to on a web site, and approxomate costs? I keep seeing in the several thousand area.... scarry.... I have only driven about 100 kms in the car i am gonna buy, and I already love the feel of the rotary... and want it. If I was to do like a preventitive rebuild, all the seals and O-rings and bearings, might that prevent needing to replace rotors and housings? Is that the only way that the housing gets damaged, by the apex seal letting go??? I don't undertstand completely the makeup of these engines yet, but have a good idea.... I am just getting kinda scared..... a guy said they will let go at 160 000 kms and this one is at 198 000 kms :eek: if thats the case... I am screwed already.... but who really knows...hopefully someone can let me know the answers to some of these questions.... the same guy that said that they will let go by 160000 kms also said that there is only one guy in Canada who can rebuild them, I find that hard to believe...... :(

Non turbo rotaries last pretty much forever, or at least longer than the body will.

Don't worry about it. Most 12As out there have between 100 and 200kmi (160 - 320k km's) and they could easily go beyond that of only the bodies would quit rusting out. I haven't heard of a body lasting more than 300k, um, I mean 480k km's, though.

- Pete (My daily driver has 250k km's on it, runs like top)

rarely will you actually see a "rotor" be bad you really only need to worry about apex seals and stuff like that. BTW Once about 2 rx-7's back i picked up a used motor for $500 with carb flywheel all accessories and header of unknown origen and it ran great. another option if you get in a pinch like i was!

I just did a rebuild on a '74 model 13b. Gasket set isn't that bad, it when u have to replace any/all of the rotor seals and springs when it becomes expensive. I replaced nearly all steel seals and springs except for side seals, including gasket set, it was aroung $780. But I'm well pleased how it turned out, Starts and runs great with 500 miles so far.

Time to dispel some myths.. :)

Yes you can do it yourself if you're confidant with tools and engines... If you've rebuilt a boinger, you can rebuild a rotary. There is a rebuild video available around here (do a search) for the 13b engine, and since the two are practically identical except for some sizing differences, it offers a wealth of information.

No, that 160,000 km thing is bullshit. Maybe with some of the *early* model rotaries, but even then.... You have to keep in mind that when rotaries made their first appearance they were only one step past prototype, and they were a technology that scared mechanics because they didn't understand it... So anything that was even marginally *bad* about those first ones stayed in the collective minds of all the retarded pisst-on gearheads and never went away.

I was at a car show in Aylmer here and there was an Rx8 there that I was walking around. The Rx8's Renesis rotary engine won Engine of the Year this year, over and above all the piston engines out there... It packs 247HP stock without turbos, and it meets all the industry standards for emissions control too. As I was looking at the car some guy came up and said "it looks nice, but I wouldn't buy one. Those rotary engines are still just prototype jap junk, I'd wait ten years for them to perfect it first"..... idiot.

Anyway, if you want to do a pre-emptive rebuild, you should change all the seals (apex, corner, oil seal) and if you've got a lot of confidance, maybe even enlarge the intake/exhaust ports a bit (porting)... :D

Learn more about the rotary at
www.rotaryengineillustrated.com
and
www.howstuffworks.com (search for rotary)

and this forum :D Welcome to the club.

Jon

I say don't rebuild it untill it starts to smoke, then you know seals are worn out, and it would be more worthwhile to rebuild it then. Even if it starts smoking due to bad seals you can still drive it for awhile.

As far as rebuilding process itself, look at spending about $800 for just all gaskets and seals. Also chances are that rotor housings are going to have to be replaced and side plates are going to have to be lapped...that will set you back another $400. You might get away without doing that last part but that's when you would have to decide what exactly you want out of your motor and how long you want it to last.

You know, it's funny. My car smokes if you run up the gears to about 7600 in 3rd then let off. But it still has killer compression.

I cracked open a used engine to port it. The dowel pin O-rings were hosing oil all over the place because it was an '83 engine with the crappy beehive oil cooler(heater) but all the internals mic'ed out perfect and the housings looked like new.

(where's j9fd3s? :) he'll tell you about 200,000mi 1st-gen motors that looked almost like new inside)

I have 120k miles on the 83 I bought new, and it runs great. Still the smoothest and best of my 3 cars; possibly because I'm the only person who's driven it. This year I have to replace the orings under the oil cooler and between the manifold and block.

The red83 I got free with 110k miles is strong as new: it has the dowel pin leak, but so what. Clean the engine once a month and don't let the dirt build up.

The 85 has 59k and runs great.

Best preventitive thing is to add 8-12 oz of MMO to every tankful.

B

Thanks for the info guys... good to know there is somewhere to get held on these motors, I keep hearing all these negative things from people, but I have a hard time to belive it, the concept to me makes sense with these engines.... I would trust someone who has 1st hand experience with rotaries rather than someone who has heard stories.....ah well, time will tell I do suppose, I am excited tho... Thanks for the welcome.

There are two rebuild videos that I know of. One is $30 from RotaryAviation.com and the other is supposed to be from Atkinsrotary.com for about $15. I ordered the former (which I have read rave reviews about), but I could never find the later for sale on Atkins rather odd 'new' site (everything still said under construction).

I had heard all the BS about rotaries:
- "they are not reliable"
- "plan on rebuilding every 100K miles, at least"
- "factor in the cost of a rebuild whenever you consider buying a rotary powered car"
- "they are too complicated"
- "very few people know how to get them to work, and they are too expensive"

When you start talking about the Gen III twin turbo, there were some problems and there were precious few mechanics that understood and could reliable fix any twin turbo problems. That is all history, and was primarily due to Mazda not ensuring that the US dealer mechanics were properly trained.

That has very little to do with the engine.

I have even heard RX-7 hobbyists claim that rebuilding them is too difficult. One RX-7 owner in Houston (he had five) told me that rebuilding requires special skills and very expensive specialized tools.

There are a few you want/need, but I bet, in total, they cost less than all the specialty tools you need for a piston engine.

take some time to learn the parts of the engine intimately (not TOO intimatley, now :D)

once you know it, all you need if a good manual like the factory manual or a Haynes manual ... i don't think the Chilton is as good as those two, but i used the Chilton on my first rebuild and it was a success.

invest in a good caliper (i think that's what they're called ... the instrument that measures the seal/bearing tolerances) because it's good to know what needs to be replaced the first time around. sadly, i didn't have that luxury with my first motor rebuild. :(