Brad Barber wrote:
"This time, the compression on the rear rotor was still over 100 psi, however, the compression on the front housing, while still around 80 ps....was only giving me TWO "bounces". Yeah, for any noobs on the list, there must be three "bounces". Also, the chugchuga wosh did not sound "right". DOH! I checked and rechecked. So, one of the front seals seems bent too. No real surprise. "
My guess would be that this is not an apex seal. Given your previous center iron problems you may still be having issues in that department, or maybe you have a warped housing that caused your center iron problem (and this problem).
The reason I feel this way is that the behavior is different cold and hot, and because it seems to affect only one combustion chamber. Apex seals generally affect two (or all three), and if they're damaged, they don't seal at any temperature. Since it's temperature dependent, it's probably a side sealing problem which is partly sealed at low temperature, but then unseals itself when it heats up and the parts expand.
I'd recommend having all your housings checked for true, probably even the front and rear, but especially the rotor and center. Also, pay close attention to the torque when you put it back together, use new bolts and make sure there's no crud in there that could mess up the torque. You know, my father had a block crack on a piston engine when a head bolt didn't fit properly even though everything was torqued correctly - I never heard of something like this on a rotary, but I tend to think both of these problems are related and it probably won't go away until whatever is the cause gets fixed.
Kelly Troyer wrote:
"I just remembered one other tidbit of info from our rotary guru Lynn.........One of
his informative posts on fuel and the effects of octane ratings stated that as you lean
the auto fuel that many of us use (87 to 91 octane) that the flame front is slowed and
this mimics the effect of lead in fuel"
Generally, leaner mixture increases the risk of detonation, regardless of octane or presence of lead. On a naturally aspirated rotary it doesn't usually matter much.
I find this page to be an excellent reference for the effects of octane:
http://www.turborx7.com/fuel.htm
"One other point that I forgot to mention was ignition timing..........It is my understanding
that turboed engines should not use excessive timing advance and that the higher the
boost the less timing advance is needed (or wise).........As I recall ignition timing as high
as 27 + degrees BTDC has/is used for naturally aspirated rotarys"
I think the confusion here is between talking about the timing at idle and the timing at high RPM. When you set the timing you are usually setting the idle timing, then the ECU adds a certain amount of advance based on the RPM, temperature, whatever. 10 degrees is probably the idle setting, not the maximum advance, whereas the 27+ is probably the maximum advance (maximum advance in my car is about 35).
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