Hi guys. I'm currently the owner of a 1990 MX-5 and have been looking seriously at RX7s for a while now too.

Currently there's a guy not far from where I live selling his 1986 RX7 non-turbo for $500 or best offer (I could probably get it for $300 or so).

The only problem is that it overheats badly even when he drives it from his house to work, which is like 2 miles, tops. Could you guys give me a rundown of the most likely causes of such a problem?

Also is it possible that the motor itself is shot? I don't even know if coolant actually runs THROUGH a rotary motor like it does a piston engine, so ignore my rotary ignorance.

 

If it overheats that bad, its probably been overheated to the point of rebuild required.

 

Should have a look a this.
http://aaroncake.net/RX-7/buy1.htm

 

even if a rebuild is required you can still make your money back if you want to. fix it if possible for cheap, if not drive the **** out of it and start saving for a turbo swap. as long as the body isnt destroyed, i say go for it. it probably has a blown coolant seal which would require a rebuild. look for coolant in the combustion chambers

 

how do I "look for coolant in the combustion chambers" ?

I thought a rotary motor only had one "combustion chamber" with a big rotor in it.

 

after reading the stuff at that link basically the answer is "if it's been overheated, don't buy it". correct?

 

An overheated rotary engine usually kills the coolant seals. This usually starts off slow: coolant seeps into the combustion chamber. You will have to top off the coolant periodically and you will blow white smoke out the tails.

The problem will get worse and worse until the car is undriveable.

 

The 13B motor in the car you are looking at is a two rotor engine. Each rotor shaped like a triangle has three combustion surfaces. Each surface (bathtub) fires every time it passes the plugs. (one leading and one trailing per rotor) sounds like a two stroke motor but not quite the same as one.

Do some searching, you can learn a lot here by searching as there is no question that has not been asked.

 

there are 2 seperate chambers, each with their own rotor. take off the exhaust manifold and look through the exhaust ports. either way, if you are looking for an rx7 project you cant expect too much with $300. its a good deal if thats what you are looking for.

 

$300 is a good price even for a rolling shell with no motor

however, if you're looking for something to drive right now into the indeterminate future, you'd probably be better off looking for another rx-7

 

agreed

 

actually I'm looking for a beater so I can save my MX5 for the weekends. An RX7 is far from what I was looking for, but for the price I figured I'd research it.

 

http://www.aaroncake.net/rx-7/cooling.htm for cooling system troubleshooting.