Q: Last year our club bought a PA-25 tow plane. It has a Lycoming O-540 G1A5 260-hp engine. We bought it with 100 hours after overhaul and flew it 95 hours, so total 195 hours after overhaul. Now the annual inspection revealed a massive contamination of the oil filter with shiny non-magnetic particles. Also some soft sealant particles (rubber or silicone) are […]
Is this converted engine reliable?
Q: We recently bored a Lycoming 290-D2 engine to accept 320 cylinders (low compression) with 8.5:1 pistons. The engine has all new bearings and valves, and everything has been magnafluxed, balanced, etc. We retained a very good 290 D2 crankshaft. From experience, would you say it could make a reliable engine? Gilles St Pierre, AVIATION BSL (Canada) A: […]
Can I use these cylinders?
Q: I have several wide deck cylinders (for a Lycoming) 360 but the deck is a little bit thinner than normal and the deck looks like it is milled or radiused around the attach nuts area on the deck. I’m not sure where I got them from, but are they early style wide deck? Can I mix […]
Should we always rebuild at 2,000 hours?
If I did my math correctly, this engine has been operated approximately 38 hours, on average per year, during the 47 calendar years of its life.
Ask Paul: SI creates confusion about exhaust valve
Q: I recently purchased a high hour O-320-A1A in an RV-3. The rocker arms were out of limits and I had them rebushed and sized. The description for the exhaust valve is confusing on Lycoming Service Instruction No. 1451A. Under the cautionary note, the exhaust valve is “identified by the oil drain hole located under the valve […]
Tips to restart an idle airplane
Q: Because of medical problems, my IO-720 has not run in six months. While always hangared, the hangar is sometimes damp. The question is what to do in re-starting? Do we open it up and clean, or change the oil often? Larry Smith A: Larry, first of all, we certainly hope all of your medical issues are […]
Ask Paul: Wide vs. narrow deck engines
Q: Big picture question here: For a 250 or 260 hp Lycoming O (or IO)-540, is there any significant reason to favor a wide or a narrow deck engine? In particular, I’m looking at buying a core for a project and there seem to be more narrow deck cores available (presumably because their host aircraft are […]
Why is the right engine oil temperature higher on my Aztec?
Q: Hi Paul, I’m wondering if you’ve ever come across Aztecs with the right engine oil temperature running warmer than the left. I’ve had mine 11 years. The right side oil temperature is usually 190°, while the left is 160°. CHT is usually pretty even. Mine came with louvers on the right side cowl, and I’ve […]
What to do about a lean mixture setting
Q: I have a PA-25-260 ag plane. When I let it idle 640 rpm, it makes a popping noise, however after takeoff, when I reduce power (slowly), the loader says he can hear a popping noise. Both mags check good and I recently replaced the spark plugs due to a drop in one mag. This fixed the […]