QuestionQUESTION: I have a 1993 Mazda RX7 Twin Turbo. I got injured and couldn't crank it for 5 months. When I went to crank it, it would make a noise like it was trying to start but wouldn't crank. I changed the spark plugs, battery, and had the starter checked which was working fine. None of this worked however. There is exhaust coming out when I try to crank it. Unfortunately, that's all I get out of it. It has 102,000 miles on the engine. I bought it used with 60,000 miles on it. I have replaced the power steering pump, radiator, ECU, spark plugs and wires, battery, etc. And it has had regular maintenance done. This is my first rotary engine and I'm kind of lost. What else could I check/replace to get it running again? Or, will I need to re-seal the engine? Thank you.
ANSWER: When it cranks over does it sound as though there is little or no compression, (ie. does it sound more like an electric motor that is free spinning) If so your apex seals have contracted and as such they are not making a compression seal. Removal of the spark plugs is required, inject 3 cc of ATF (automatic transmission fluid) or Marvel Mystery oil into each plug hole, reinstall the spark plugs and attempt to start again. The light fluid will make a temporary seal between the apex seal and the rotor housing which should bolster compression and allow it to fire over. If it doesn't work the first time do it again this time letting it sit for a few hours. Hand rotation of the engine may also be required before attempting to fire it up. Once it is running let it come up to temperature and be sure it is running clean on both rotors before shutting it off, it will smoke until it burns off the ATF or MMO. Marvel Mystery oil can be added to the fuel and oil also, read the can. It's an old school trick but works well with older rotary engines.
Apex seal wear is very common, oil metering systems can become less efficient or even fail without warning which leads to premature seal failure. It is advisable to use a light mixture of 2 cycle oil in the gas to help extend and insure proper secondary lubrication in a rotary. Be sure your spark plugs are clean or new. If you are not aware the rotary consumes it's own oil as part of the secondary lubrication system hence the design of the spark plugs and all the more reason to keep them clean or new.
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QUESTION: The best way I can describe it is, when you turn the key in the ignition it does not sound like anything in the engine is moving, and it just kind of goes "rrrrrrr". I appreciate your help and I will try that and let you know if it works. Thank you again for your help!!!!
AnswerApex seals. No compression, you need to follow my previous instruction to get it started again. This could be a sign of things to come so once you get it running keep it running on a daily basis so these seals do not contract again. Also, put 2 ounces of 2 cycle engine oil in the gas tank with each fill up to aid in secondary lubrication this will extend the engines life and safe guard in case the engines own oil metering system breaks down.
