QuestionQUESTION: I have a 91 rx7 with the rotary engine. Engine is currently out of the car on a stand. When I turned the motor it spat out what looked like coolant with some oil out of the exhaust port. Should I have the engine rebuilt? Thanks.
ANSWER: Was is smoking (white smoke) when it ran last?
Sounds like worn side seals.
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QUESTION: It was white smoking mostly on start up but there was visible amounts of smoke while it ran too.
AnswerWhite smoke is a sign of coolant or water entering the combustion chamber, blue is oil. Though a small amount is not uncommon during start up at times due to moisture in the exhaust system. If it continues after warm up then a fault can be assumed.
Having a presence of raw oil and water in the exhaust port is a sign that a rubber seal or seals between the housings are leaking. Which port is showing sign, front or rear or both?
You have the front cover, a seal, front rotor housing, a seal, the intermediate housing, a seal, the rear rotor housing, a seal and the rear housing. Due to how the motor is assembled it is likely a complete tear down is required. Due to tooling required doing it yourself may prove to be a challenge but not impossible. There are a handful of shops that overhaul these engines but mostly to higher performance standards which means more cost, Mazda has a rebuilt exchange option. They have a facility state side that overhauls them to Mazda OEM specs. This is NOT a job for a general repair shop, most have no clue what the engine is. Changing just the seals is possible however, if any machining is required due to wear only a few places state side have the machining capabilities required for rotor housings. Tear down might be a perfect chance to upgrade the apex and side seals. If you end up ordering a replacement engine be very specific about the configuration of your motor. (ie auto/manual, turbo/non, fuel injection/carburetor. The front, intermediate and rear housings can vary by application.
