ok, so i bought a '89 rx7 gtu about 2 weeks ago, 2nd day driving it it went from running great, to misfiring and stalling. i just finished replacing the intake manifold gasket, fuel filter and a few other small things. unfortunetly for me i just did a compression test and the front cylinder is reading about 85-90 psi, but the rear is at 30 at best. is there like a spring mechanism that could have gotten jammed or something like that ... because i dont think compression disapears like that in a split second. and is there any way to fix it without tearing the engine apart or pulling it out ? if i do need to replace the seals i may need to recruit someone on here that has done that before because i dont have the time, space, tools or knowledge to do that, im in the chicagoland area so if anyone has any ideas or suggestions for things to try before i go postal on the car please let me know. also how much are the parts for a rebuild and labor normally ? if i cant get this project done for less than 1000 bux im going to have to sell the car and cut my losses. thanks for any input guys.

 

You'll be hard pressed to get it done FOR YOU for less than 1k (including shipping)... But, it sounds like you'll need to rebuild for sure... You probably tossed an apex seal or atleast chipped one... If thats the case, the rear rotor housing, rotor, and possibly some irons are toast. Lots to replace... Would be cheaper and easier for you to just find somebody LOCAL with a cheap RUNNING engine. Or, find another 89-91 non turbo thats all munched up from an accident or something... and buy it for cheap.. pull the engine, gut what you can... and toss the rest.

 

"because i dont think compression disapears like that in a split second."

It can, and did in your case. Sounds like you blew an apex seal.

Also, they are not cylinders, they are combustion chambers created with rotors and housings.
http://en.wikipedia.org/wiki/Wankel_engine