Good rotary engines are getting harder and harder to find. There for awhile you could buy a running 2nd gen RX7 car and strip the engine out and junk the rest of the car. The problem now is the price of those cars are going back up. Beware of any junk yard engine as sometimes they let them sit outside and they fill up with rain water. After that the engine is scrap.

One of the problems Mazda had with the 89 to 91 engines and maybe later
was a failure of the end housings. It probably was due to the fact they did not
change the casting patterns when they machined the O-ring grooves in the end housing instead of the rotor housings. Slight imperfections in some
of the iron castings caused them to crack and leak fluid into the combustion chambers. The engine would run once you got it started. If you let it sit
the water would rust the inside of the end housing on the wear surface.
To overhaul an engine like this requires a new or used end housing which adds greatly to the cost of overhaul. Better to test it before you buy it.

So I came up with a test procedure for checking for this type of problem.
I pressure tested the water jacket to 30 psi with this rig.

The RX8 engines have the O-ring grooves back in the rotor housings so this
is no longer a problem.

This engine passed the water jacket pressure test with flying colors although the engine was locked up when I got it. I filled it with automatic transmission fluid for a few days and it unlocked. Apparently, and for some strange reason, there is a powerful detergent in ATF. I am going to build a tank big enough to soak the whole engine :)

Next test is to check the compression.

Paul Lamar