Scott DellAngelo
Well Known Member
First my e-mag/p-mag ignited RV-9A seems to be running well (just over 10 hours). Just for the info, I have a carbureted 9:1 O-320 with FP prop. I "think" that my baffle job is good and I see signs of sealing all around the top of the cowl and everything is tight and every hole I can get too is RTV'ed to prevent leaking. I have the timing in the low advance setting and have backed the initial timing an extra 2.5ish degrees ATDC (per their manual, and also they did go back about a month ago to be re-mapped or whatever the change was). I really saw no difference in CHT between the 2.5 degrees after and at TDC (perhaps I should go more??). Anyways I run just barely under 400 degrees on 1-2-4 and just under 425 on number 3 while cruising in the 2000-4500 foot range at 2500 rpm and ~25 inches MP (FP but I do have a MP gauge). I am not surprised that 3 is the high one since 4 has the oil cooler there which probably allows better flow around that cylinder. These numbers are with no leaning and do not seem to have changed at all in the 9.5 hours of flight. Engine is using little to no oil so I am guessing it is broken in by now.
After all that, my question is should I continue to retard the timing, or should I leave it alone? The numbers are okay right now according to the Lycoming manual, but when I go from 40-50 degrees to 90+ in the summer I am afraid that will help bring them up to a little too much. I understand that numbers will be somewhat higher with EI than non, but I am unsure how much "higher" means. Any advise would be appreciated. Also I would guess my cooling will be just a little bit better with fairings to pick up more speed, but I would imagine that change to be slight.
Thanks,
Scott
#90598 - N598SD Flying (~10hrs)
After all that, my question is should I continue to retard the timing, or should I leave it alone? The numbers are okay right now according to the Lycoming manual, but when I go from 40-50 degrees to 90+ in the summer I am afraid that will help bring them up to a little too much. I understand that numbers will be somewhat higher with EI than non, but I am unsure how much "higher" means. Any advise would be appreciated. Also I would guess my cooling will be just a little bit better with fairings to pick up more speed, but I would imagine that change to be slight.
Thanks,
Scott
#90598 - N598SD Flying (~10hrs)