You are correct in that there are coolant seals between the housings that can fail and leak coolant into the chambers to be burned plus let compression pressure leak out into the coolant system to push coolant out the overflow. You'd still see coolant loss, obviously. Plus you'd have plugs that showed evidence of coolant on them or at least being cleaner than normal.

Your issue just about has to be fuel or oil related.

Exactly how much smoke are we talking here? I've never seen a turbocharged, open exhausted, no cat convertor having, ported rotary that didn't smoke SOME. As bad as some of us hate to admit it, it's sort of the nature of the beast.

 

Too much smoke to tolerate, especially in a town where the EPAs emissions research HQ is located!

This is starting to make sense to me... I said early on that I couldn't tell if the smoke was from oil or coolant... maybe because its the 112 leaded. I gotta sleep on this. Thanks!

 

let it sit overnight, yank the leading plugs and roll the engine frontwards/backwards, see if coolant comes out, if it's coolant leaking by it certainly will end up in the combustion chamber after shutdown

 

Better, remove your EGI fuse, crank the engine (after sitting overnight or whatever) for a second or 2 then remove both leading plugs and inspect for oil or coolant. Don't expect either, though, unless you have a serious problem.

 

I think your first suspicion was right. I removed the heat sheilding and found a light oil film around the bolts and retainers holding the turbine housing to the center. Looks like an oil leak. Some of the observations that threw me off the right trail are that the cold start didn't start to smoke until the engine was fully warmed up, and the spark plug observations. I'm thinking that the seals in the turbo are just starting to fail, and the cold oil is too viscous to penetrate the seal until it's well warmed up???? And the carboning up of the plugs is probably from running over rich on the 112??? When I ran 21lbs with the 110, the trailing were definately tannish. Can going to 112 without a/f adjustments result in carbonation of the plugs???

 

if the smoke started when you dumped 112 in, then run that tank down and re-fill it with 110, like you said you were running before the smoke started, and see if that cures your problem. if you changed something and it causes your car to do something funny, then go back to how you were before the problem, and see if that cures it.

 

I'm having a very similar problem.
https://www.rx7club.com/forum/showthread.php?t=427164

I say pull your turbo and see what you get. I pulled mine and you can see what it looked like in my thread, so you can compare. The manifold and the blades of the exhuast turbine wheel were brown. Yet the tips of the blades and the turbine housing were wet with oil. I still have not gotten to the bottom of my problem, but the fact I found oil in the turbine housing tells me I'm blowing oil past the turbo's seal.

The question now becomes why. I don't think I'm running higher than normal oil pressure (for my second gen) but it might be enough to blow by the seal. So I'm going to try and run a restrictor in the oil feed for the turbo. I'm also going to take a close look at the oil drain for the turbo, there may be a possible restriction there or something. I was also under a situation of running VERY rich. So bad my oil would become highly contaminated with fuel. I'm wondering if the thining of the oil with fuel and the change in the oil would allow it to pass by the turbo seal.

Like I said I would pull the turbo and see what's going on. Keep us posted