Ok, so I've searched and seen things both ways. Anyone have some definitive experience with using fuel cut on decel when you pre-mix?

I've currently got it turned off, but may turn it back on. On an S4, when you're off-throttle there's so little oil being fed into the OMP I don't think much makes it into the engine, but that's just an assumption on my part.

I would think the film left behind by the TCW-3 oil would be ok fro the short distances usually involved in decelerating, not to mention what has been soaked up by the housings.

Any experience with this? I know I've played with an engine that's been out of the car that had pre-mix run in it and it stayed lubed for quite some time, but that is a different situation.

 

You'll be fine. Premix does leave a protective film behind, and the engine under fuel cut deceleration is experiencing basically no significant loads - there's no combustion forcing the apex seals out, so it's spring & centripital forces.

The whole point of premix is to leave a lubricating film behind - that's how it works. I have a S4 NA, 20k miles on a rebuilt engine with fuel cut intact & running premix the entire life of the engine. I engine brake quite a bit, and I've never worried about it at all.

Don't worry about it. The early rotary engines didn't have anything for seal lubrication, and they were able to run fine.

-=Russ=-

 

you are wrong about the no lub, they just used eytholine glycole