swisseagle
Well Known Member
Hello
Found this during a borescopie on a buddys engine:
- RV-7
- TMX-IO-320
- Built in 2010
- First run 2015
- 140h since new
- AVGAS only
- Cruise 50-55%
- Sensenich metal FP prop
- Recently 10-15h formation flying with slow partner, 28-32% power
- Compression is 77-78 @80psi
- CHT during the first 10 flight up to 425°F, then going down to below 400°F and now around 385-395°F @ TO and climb.
- Lycoming cylinder, light blue marked, seams to be Nitride-hardened cylinder barrels
Interestingly, when engine is cold, prop turned by hand, I can feel different compression strokes.
Two where strong, one a bit less, and one feels a bit weak. When engine is hot, this "differences" go away.
All the deposits are in the lower end, about 25% away from BDC.
Cyl 1:
Piston pin marks visible.
Cyl 2:
Cyl 3:
Cyl 4:
From where does this come from?
What to do?
- Continue flying the plane without risking something bad? All is fine?
- Fly max. one season and then take off jugs, hone and build up again?
- Stop flying immediately and take off jugs, hone and build up again?
Thanks alot!
Dominik
Found this during a borescopie on a buddys engine:
- RV-7
- TMX-IO-320
- Built in 2010
- First run 2015
- 140h since new
- AVGAS only
- Cruise 50-55%
- Sensenich metal FP prop
- Recently 10-15h formation flying with slow partner, 28-32% power
- Compression is 77-78 @80psi
- CHT during the first 10 flight up to 425°F, then going down to below 400°F and now around 385-395°F @ TO and climb.
- Lycoming cylinder, light blue marked, seams to be Nitride-hardened cylinder barrels
Interestingly, when engine is cold, prop turned by hand, I can feel different compression strokes.
Two where strong, one a bit less, and one feels a bit weak. When engine is hot, this "differences" go away.
All the deposits are in the lower end, about 25% away from BDC.
Cyl 1:
Piston pin marks visible.
Cyl 2:
Cyl 3:
Cyl 4:
From where does this come from?
What to do?
- Continue flying the plane without risking something bad? All is fine?
- Fly max. one season and then take off jugs, hone and build up again?
- Stop flying immediately and take off jugs, hone and build up again?
Thanks alot!
Dominik
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