glider_rider
Active Member
I'm somewhat surprised by what I saw inside the cylinders of my IO390 EXP 119 during the 100 h inspection. Some background: stock RV14 EXP configuration, one magneto, one Pmag. In cruise CHTs in the range 350-370 F. On longer flights I operate slightly LOP, short flights are ROP. Aeroshell 100, 100W, 15W50 and recently W80plus. All in all 4 oil changes during those 100 hours.
Coming back to horoscope picture:
1. all piston heads are covered with black residue
2. "something", maybe cooked oil builds up on intake valve guide on cyl 2 - the hottest one
Is this normal / expected ?
How do I get rid of the black stuff ?
How do I prevent it from re-appearing?
Coming back to horoscope picture:
1. all piston heads are covered with black residue
2. "something", maybe cooked oil builds up on intake valve guide on cyl 2 - the hottest one
Is this normal / expected ?
How do I get rid of the black stuff ?
How do I prevent it from re-appearing?