N941WR
Legacy Member
While on the way to Sun and Fun I noticed #3 cylinder?s CHT was running about 50 degrees higher than the other three.
When running on just the right ignition #3?s CHT came down in line with the other three. When running on the left ignition the #3?s CHT went even higher as did its EGT.
I have since replaced the left magneto, the spark plug fired by the left magneto and checked the plug wire for continuity. The left magneto was fine and timed properly, the spark plug looked good but was replaced anyway, and the plug wire checks out fine.
The baffling has not been changed since the Phase 1 period has been completed.
I?m running P-mags but I?m certain they are working fine. P-mag specific issues that I?ve tried: The timing jumper is in place and has been. The vacuum advance is plugged, which limits the timing advance to that of a standard mag. The timing is right on, as I said earlier. I really doubt it is the P-mag. I'm about to swap the P-mags left and right to see if the problem follows the P-mag bug since I've changed out the left one and the problem remained, as I said before, I don't think it is the P-mag.
On the ground the temps of all four cylinders come up together, it is only under load that there seems to be a problem. I now find myself flying by CHT temps rather than RPM. For instance, in yesterday?s flight I was running 64% power at 2500 RPM and the CHT?s were around 360 for 1, 2, & 4 and 400 for #3 while running 120 degrees rich of peak.
It has been suggested I do a compression check on this cylinder but it is my understanding bad valves will lower temps, not raise them.
Any thoughts?
BTW, the engine is an O-290-D2.
When running on just the right ignition #3?s CHT came down in line with the other three. When running on the left ignition the #3?s CHT went even higher as did its EGT.
I have since replaced the left magneto, the spark plug fired by the left magneto and checked the plug wire for continuity. The left magneto was fine and timed properly, the spark plug looked good but was replaced anyway, and the plug wire checks out fine.
The baffling has not been changed since the Phase 1 period has been completed.
I?m running P-mags but I?m certain they are working fine. P-mag specific issues that I?ve tried: The timing jumper is in place and has been. The vacuum advance is plugged, which limits the timing advance to that of a standard mag. The timing is right on, as I said earlier. I really doubt it is the P-mag. I'm about to swap the P-mags left and right to see if the problem follows the P-mag bug since I've changed out the left one and the problem remained, as I said before, I don't think it is the P-mag.
On the ground the temps of all four cylinders come up together, it is only under load that there seems to be a problem. I now find myself flying by CHT temps rather than RPM. For instance, in yesterday?s flight I was running 64% power at 2500 RPM and the CHT?s were around 360 for 1, 2, & 4 and 400 for #3 while running 120 degrees rich of peak.
It has been suggested I do a compression check on this cylinder but it is my understanding bad valves will lower temps, not raise them.
Any thoughts?
BTW, the engine is an O-290-D2.