RX-17

i dont really know wut to say but just read...

http://www.mototuneusa.com/break_in_secrets.htm

johnnyg

That seems oddly logical!

I was taught that you should take it easy because the rings will chatter against the honed cylinder wall and might actually break. But I also recall the break-in procedure for an '99 Grand Prix GTP I had which was similar to this "secrets" technique. The manual said that it's best to avoid staying at one speed, suggesting you accelerate quickly, then engine brake. Or something to that effect.

RX-17

hmm i find it quite interesting. With everything that he says it sure seems that its really logical but i dont know how true his facts and statements are. Do you think it could hold any ground for rotaries?

johnnyg

Well, if it really does help piston rings seal better, then I suppose it would help with a rotary too. But I still question this whole thing. If expansion pressure really does force piston rings against the cylinder wall, then where does it go after that? Wouldn't there be blow-by into the oil pan? How could the gas get behind the piston ring, but not past it?

Regardless of that, if pressing an apex seal against the housing wall would help with sealing (and it seems obvious that it would), then centrifugal force would certainly do the trick with a rotary. And that means high RPM. Which is exactly the opposite of the "standard" break-in procedure for a new motor!

I still think chatter would be the real enemy here, but I'd love to be in a position to test the theory!

locketine

well for a rotary, as I understand, the break-in is just wearing the seals into their respective grooves. Why you can't go high rpm I would imagine is because our rotors are basically banging around inside the houring and the aprx seal is there to absorb that force, but if they aren't fully seated such a situation could very well dislodge the seal or dent something. Same for going WOT during break-in, except it's the explosion you're worried about then.

johnnyg

Banging around? The motion is geometrically perfectly smooth. And, all 3 tips of a rotor are continuously in full contact with the housing, so I don't see how you could dislodge a seal.