- Joined
- Oct 31, 1996
- Posts
- 1,210
- Type aircraft owned
- Carbon Cub FX-3
- Base airport
- KFCI
- Ratings
- COMM, IFR, MEL, SEL
My CubCrafters cc363i (Lycoming IO-360) has automotive spark plugs using a 18mm to 14mm adapter. I've been doing my compression checks and got 80/80 and then this year decided to get a borescope and let my maintenance shop do compression testing. I was surprised at first that they removed the adapter which I had planned to never remove, not a big deal, but they got 76/76. This makes me wonder if compression checks are different at 14mm vs 18mm? I also realize compression testing is not a science, the accuracy seems suspect at times.
