Quick report: With over 400 hours on my engine, I was in the process of testing the pressure differential across various points on my cowl in search of more effective outlet for cooling air.
The idle has been getting rough for the last several weeks, and my testing runs made me think it was getting worse. Since we all know it is important to "listen" to your engine when it is speaking to you, I started (again) to try to track down the cause. New plugs would help but only for a few minutes. Tried switching coils and injectors on and off, but no change. Seemed to be running very rich at idle no matter what I did. Manual leaning would not make it smooth, but it would kill the engine! All was smooth above about 2500 rpm.
Finally pulled the schrader valve from my compression tester and spun it with the starter. Rotor one was a nice 100-100-100 for bumps. Rotor 2 was 60-60-85. Oops. Looks like a bad apex seal?
Just tore it down today and attached is a photo of the broken apex seal. Also found a chip from the outer (compression side) oil seal on that rotor. Not shown are the SIX missing (melted??) rubber plugs from the corner seals, and two corner seal wire springs that are completely missing! The ones remaining are completely flat and looked like they were disintegrating from heat.
Rotor one looked to be in good shape all around. Rubber plugs were hardened, but still functioning, and the wire springs were springing.
I can see that maybe if the rubber plugs melted, it would allow the small triangular part of the apex seal to drop down and somehow allow the longer piece to break. Does this sound reasonable?
LARGER QUESTION: It is obvious to me that a LOT of heat was generated to melt the rubber plugs on BOTH sides of the rotor. Does anyone care to venture a guess as to why that rotor was so much hotter than the other? The EGTs were within a few degrees most of the time. I will double check the oil jet that cools the rotor tomorrow.
(Jason just about has his 3rd gen back together. I am eyeing the size of his intake ports....................) -- Bill Eslick www.weslick.com |