My buddy just picked up a 91 N/A for dirt cheap. The body and interior is mint, and it was his understanding that it might need a new engine, so he already knows what he's up against. Paid $400 Cdn. the previous owner said the car wouldn't go above 80kph...took it to the dealer, they did a compression test...came back 6.7 6.5 6.7 on the front rotor, 7.0 7.0 7.1 on the rear with 235K on the odometer. They said it needed a rebuild...any opinions? I haven't had a chance to get the car into the garage to do any of my own testing...

 

The Rx7 work shop manual for 1989-91 engine says that the compression pressure per rotor is 6.0 to 8.5 kpa. The maximun difference between one rotor and the other can be 1.5 to 2.1 kpa. So, with the number that you give there is no problem with the engine because the compression number would be between the range. The compression ratio for the N/A engine is 9.7:1 and for the turbo engine is 9.0:1. Maybe the problem of the engine if lack of fuel, air leak, incorrect timming, throttle body not open complete. Check also the sparkplugs. Also, engine that stay a lot of time and there is in not use, the apex seals froze and the compression is not the correct: the solution: install new springs. Good luck.

 

other than looking to other areas of the car, like you've suggested, my thought was the seal springs were gummed/stuck. can the ATF'seafoam trick free them? I realize this is the last alternative to a rebuild, but I don't wanna try if there's no possibility of success.