Hi, first time poster here....

Anyway, I have an '85 rx-7, and the 12a motor has bad compression, presumably because of busted apex seals.

I'm looking to replace the motor, but a new one is out of my price range. I can install it myself, but a rebuild is beyond my expertise. I have about $1000 to work with. Maybe a little more.

Having looked around a little, I know I can get a warrantied used motor for ~$900. Is this a good option? Otherwise, I would need to have a shop rebuild the current motor, which would likely cost much more than $1000, right?

About how much would I be looking at to have it rebuilt by a reputable shop, and does anyone know of such a shop in the west-central Illinois or St. Louis area?

Basically, I'm looking for advice and opinions as to what is the best course of action. Any input would be appreciated.

 

Whatever direction you decide to go get yourself a 13b and take it from there.

 

Is that a direct bolt-in, or is it more complex? Cost is an issue here.

 

Not a direct bolt in.

Your best bet if you can get a rebuilt engine for $900.00 with a warranty and from a reputable rebuilder is it.

 

The $900 motor is a used, non rebuilt one with 60,000 miles.
Would it be possible for me to get a rebuild for around $1000 at all? This would be much preferred.

 

Check these sites for prices.

www.atkinsrotary.com

www.pineappleracing.com

Also check the 1st gen classified parts section. There are atleast 2 12a engines for sale in there now. :-)

 

You know what I think?

https://www.rx7club.com/showthread.php?t=687745

I mean cmon. If I had the cash I would do this! Sure, it will take time and some custom work, but you CANT beat the price!

 

rx7doctor:

Though a pro rebuild from either of those companies would be really nice, they are simply beyond my budget. Both ask well over $2000 for their basic rebuilds.

 

Let me ask you this. Are you relying on this car right now for transportation?

 

Well, not exactly. Let me tell you a more complete story:

I am a college student living at school, so I don't really need the car. It would be nice to have it for going home periodically and making runs into the city, etc. But I won't have any trouble living without it for now. And it does actually run, just very poorly.

However, come my winter break I will need it or some other transport to get me to and from work.

If you're thinking I should wait until I can afford a nice rebuild, I think I'd find it very hard to justify spending that kind of cash on this thing, especially when I think what else I could have bought for all the money I would have poured into it.

 

You'll be lucky to find a shop that will rebuild the motor for your budget, considering a rebuild kit alone is about $1000. I've been quoted about $2800 for a complete rebuild with some porting by two shops. Buy a decent shop manual and if you have the time, pull the motor and rebuild it yourself. It's good experience. Otherwise work your *** off and save some more money.

 

I've thought about doing the rebuild myself, and I would love to gain the experience, but having read through a shop manual it seems like it's probably too big a job for me.

I can get access to the required tools and a workspace, but I wouldn't feel good doing a rebuild without someone to guide me. I have people willing to help with a motor swap who are experienced mechanics. But none of them know rotary engines, so they're skeptical about a rebuild.

Also, with a rebuild kit alone costing as much as a running, warrantied used engine, I don't think I can justify it. And suppose I tear down the motor and find that the housing is warped or something like that. What then?

 

The busted motor has 90,000 miles, BTW.

 

First of all, you are assuming that you have internal problems with the engine. Have you performed a compression test on the engine?

 

I took it to a mazda dealer and they did the test.

The external symptoms are poor power, lots of soot in the exhaust implying a very rich mixture, and inability to idle. I have to use the choke whenever it's idling to hold it above 1500 RPM. Otherwise it dies.

As I understand it, these are all consistent with blown apex seals causing bad compression.

 

If you want to find out if you have a blown apex, Remove the leading plug on the front housing and turn the engine over by hand. You should hear 3 wooshes. Put the plug back in and do the same for the rear. If you hear 3 on each, then your motor is making SOME compression on each face of the rotor. If you hear 2 or less, then yeah. Blown apex or corner seal.

This is a simple test that should only take 5 minutes or so

 

Oh, and even though this is a stretch, it could mean the difference between a rebuilt motor or a rebuilt carburetor!

 

What test did they perform? If it was a compression test then they would have given you a print out with the results and would of definitely been able to tell you whether it has bad seals?

 

Mazda dealerships in Illinois are notoriously bad in my experience... try getting a real compression test with a printout... btw what school are oyu goign to up there?

 

Why not buy another beater for $1000 and sell the rx7? It really doesn't sound like you're enthusiastic about it so you may as well take the sane course of action here.

 

The problem is that it clearly says he needs to "Plug in the driveshaft + ECU and go."...so that old ECU is going to blow his budget way past $1000...just get the $900 and drop it in. That's your best course of action. At 60,000 miles, you've got at least 120,000 left on it. Plenty of time to learn about rotaries and RX-7's and start saving for the inevitable 13B turbo swap.

 

With only 90,000 miles what are the chances it only has a sticking apex seal(s)? Search the threads for sticking apex seals and try those tricks first. You're already assuming the engine is bad and are ready to replace it, so you're not going to be out anything but some time and $5.00.

 

Not to hijack your thread or anything but I am in a similar situation as you. Fortunatley my car is a long term project that I do not use as primary transportation. If you want to get this thing on the road, I would try to find a known working used 12A and throw it in there.

As for myself, I have a 12A that I was told has blown apex seals. I will need to break the rotors free before the starter can even crank the engine but since it has not run in 3 years, I will probably yank the motor out and put in a 13b or 302 depending on the funds. Re-building the 12A would be great experience though.

 

If you noticed, he is giving away the ECU along with the deal. I know it will be over a grand, I was just tellin him about a deal as well. IMO, I would go with this 11000 mile S5 motor than a 12a with 60k on it, especially since if he does not pick the 12a up himself, that shipping would put him over 1000 as well. For a noob, yeah. 12a all the way.

 

The dealer didn't give me a printout, so I just called them back asking about it. They have it, but the guy who answered my call was unable to interpret it and all the techs are gone for the weekend. I'll call back on Monday.

I might not sound very enthusiastic about this thing, but that's at least partially because I'm just so frustrated with it now. However, in working order it would definitely be more fun than any $1000 beater I could get around here. Plus I would value the experience of working on it. This is something that I do want to learn.

And the school is Knox College in Galesburg.