I have begun to see lower CHT and EGT on cyls 1 and 3 lately at idle, with EGT not even registering on my MGL Odyssey display until runup. At runup RPM, all temps seem pretty even on all cyls. CHTs are about 50F less than the neighbors but are reasonable. At max power on takeoff the EGTs are slightly higher +50F than the other cyls - just over 1500. At cruise WOT all CHT/EGT readings are very similar on all cylinders. Reducing power sends the EGTs higher on 1 and 3 than the others. Mag drops seem fine and similar on both.
When I changed the oil I noticed that I have some dark oily varnish to the left of the plugs and dripped down the intake pipes near the intakes on 1, 2, and 3 cylinders. I suspect that maybe there was some oil was finding its way out around the intake gaskets. I was also thinking that an air leak here (too much induction) at low RPM could make it too lean to fire and explain low rpm pops on the right side of the engine which I sometimes hear, and might explain lower CHT at idle.
So, I am going to change the gaskets on the intakes and also the EGT probes - two of which have been replaced in the past three years for bizarre readings. This may be more of the same related behavior, but I want to be sure.
Anyone else seen such behavior with their Lyc 540s or its sensors? Other suggestions or thoughts would be appreciated.
When I changed the oil I noticed that I have some dark oily varnish to the left of the plugs and dripped down the intake pipes near the intakes on 1, 2, and 3 cylinders. I suspect that maybe there was some oil was finding its way out around the intake gaskets. I was also thinking that an air leak here (too much induction) at low RPM could make it too lean to fire and explain low rpm pops on the right side of the engine which I sometimes hear, and might explain lower CHT at idle.
So, I am going to change the gaskets on the intakes and also the EGT probes - two of which have been replaced in the past three years for bizarre readings. This may be more of the same related behavior, but I want to be sure.
Anyone else seen such behavior with their Lyc 540s or its sensors? Other suggestions or thoughts would be appreciated.
