walkman
Well Known Member
Background: 2004 Superior XP-360 approx 950 SNEW. Bendix RSA-5 FI.
Purchased aircraft in Feb, 78+/80 all around. My inexpert borescoping showed nice shiny valve edges, "bullseye" look to exhaust valve faces, no scoring in cylinder walls, honing pattern visible.
All oil analysis since new look good, but high aluminum constant since new, but not vastly high and no spikes, not increasing.
Put a little over 100 hours on it in 7 months, lots of formation, some LOP cross country, a little acro. 2 oil changes. oil seems to go black quite quickly. always lean aggressively on ground, usu. lean to 10 gph for formation work. aeroshell w100 with ASL camguard
CHTs rarely over 380, mostly 340's except even lower when LOP cruising. Even in hot, high power climb out CHT's 380 or below.
Very rough running has slowly developed when the engine was hot, has gotten worse slowly. engine fine when cold, but 10 minute taxi and starts idling roughly. makes good power when airborne. all plugs, intake gaskets, hoses are new. plugs all tested.
Compression test 3 weeks ago showed 79 on 2,3,4, 68 on #1. Ran another 10 hours. comp test yesterday 2,3,4 all the same, #1 below 60.
Another borescope valve edges and faces look great. Can't see the seats. both smooth and no sticking in their travel. cyl walls on #1 MAY show some vertical scoring in bore up at top in choke area, this may or may not be normal, my lack of experience here. sorry no pics.
Hard to tell where air is leaking during compression test (full inverted oil system) but I don't think its valves, so where else but rings?
I'm thinking its time to pull this jug and look see. broken rings maybe? before I do, does anyone have another opinion?
Purchased aircraft in Feb, 78+/80 all around. My inexpert borescoping showed nice shiny valve edges, "bullseye" look to exhaust valve faces, no scoring in cylinder walls, honing pattern visible.
All oil analysis since new look good, but high aluminum constant since new, but not vastly high and no spikes, not increasing.
Put a little over 100 hours on it in 7 months, lots of formation, some LOP cross country, a little acro. 2 oil changes. oil seems to go black quite quickly. always lean aggressively on ground, usu. lean to 10 gph for formation work. aeroshell w100 with ASL camguard
CHTs rarely over 380, mostly 340's except even lower when LOP cruising. Even in hot, high power climb out CHT's 380 or below.
Very rough running has slowly developed when the engine was hot, has gotten worse slowly. engine fine when cold, but 10 minute taxi and starts idling roughly. makes good power when airborne. all plugs, intake gaskets, hoses are new. plugs all tested.
Compression test 3 weeks ago showed 79 on 2,3,4, 68 on #1. Ran another 10 hours. comp test yesterday 2,3,4 all the same, #1 below 60.
Another borescope valve edges and faces look great. Can't see the seats. both smooth and no sticking in their travel. cyl walls on #1 MAY show some vertical scoring in bore up at top in choke area, this may or may not be normal, my lack of experience here. sorry no pics.
Hard to tell where air is leaking during compression test (full inverted oil system) but I don't think its valves, so where else but rings?
I'm thinking its time to pull this jug and look see. broken rings maybe? before I do, does anyone have another opinion?
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