If anyone missed it, my oil level is also rising. This change it was about 1-2cm above the F mark on the dipstick. FWIW, I don't have an OMP.

 

Oil control rings can definately contribute to the problem. As well as bad sideseal clearance. A rich tune/flooding can contribute as well.

On turbo cars this is very common, due to positive manifold pressures and richer mixtures under boost.

 

I had asked my builder about my oil level rising due to (I assume) gas mixing and he said it was probably me running rich. Still though... 6% gas?

 

It's normal for some gas to get in the oil no matter what, but this sounds like more than normal for a non turbo. I don't remember if you said it was ported or not, but some porting styles can contribute to this(the ones that go into the oil control rings).

I wouldn't be too worried, maybe consider running a higher quality oil and change it more often. I change every 5000 km and run mobil 1 15W50. Mine comes out black and smelling like gas every time, as does most turbo rx-7.

 

It's got an auxiliary streetport, so I doubt that's the problem. This was changed after 1500 miles. I'm going to change this next oil after 1500 miles and see what happens. Maybe the damage was done from when I ran 10w30 for a while and the results coming up are from the oil left in the cooler. If the next results are the same I'm probably going to go synthetic and see how that turns out.

 

I just requested the free kit, provided a link to this thread, and hinted they should offer us a group buy...

 

Here's another comparable. Engine has 70K original miles on it. Good compression. Not raced as Blackstone states, but run at a half dozen track days a year. They misinterpreted my comments on the sample submission form.