so I know my rotaries pretty well and I am baffled by this one.

My FC (n/a) smokes only on high revs but only after I let off the gas. To be clear, I can redline the motor with no issues, but as soon as I let go of teh gas it will smoke. This happens under load and without load. It only happens if revved past 4k.

In the last week this is happening I havent lost enough coolant or oil to tell if it is eaither of them. But no bubbles in the fill cap.

The smoke it white, slight tinge of blue, but not enough to tell if its just what the engine useually burns or more. It doesnt smell to sweet, just really odd. Nothing is dripping on my exhaust.

I rechecked compression and I havent lost any since I checked it 2 months ago (my numbers on one rotor isnt great, but it hasent smoked for 6 weeks on the average numbers)

Any ideas?

 

What's the mileage on the engine? The oil control rings will start to let oil seep past with time. It doesn't take much to make some smoke.

 

Worn oil control rings. When you let off at high rpms, it creates a strong enough vacuum to pull the oil past the c-rings. My last motor developed this issue after I overfilled the crank case during an oil change, but it will also happen with age.

In my case, it was blowing out so much smoke that other drivers had to pull off of the freeway when I went by. I had to fix it quick because it is also my daily driver. I found that replacing 1 or 2 quarts of oil with Lucas Heavy Duty Oil Stabilizer (damn that's a long name) got rid of about 95% of the problem. The only time I would blow smoke after that was during autocrosses, when I would let off the throttle at close to 8,000 rpms. Daily driving produced no smoke.

The only way to actually "fix" the problem is with a rebuild. But the Lucas may help you to live with the problem, or maybe even eliminate all symptoms of the problem. For some of us, that's good enough to consider it as an option.

Good luck.


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