What are the best options for overhaul?

Q: My question seeks your advice about an overhaul on our Lycoming O-320-H2AD. As background, we have a 1980 C172N that’s been owned since new. It’s always been hangared, never been a flying club or training airplane, is not used for commercial purposes, and has 2,420 TTAFE tach time.

The engine is the original H2AD and it has not been topped. [Read more…]

Ask Paul: How do I know if this AD applies to my engine?

Q: I’ve heard there is an AD that prevents various Lycoming engines from being signed off as airworthy if the TBO is exceeded. I’ve also heard it doesn’t apply to engines manufactured prior to 1970. If the engine was original in the 1960s but remanufactured after 1970 would this AD still apply or would all parts used for remanufacture be exactly the same as the original parts?


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Ask Paul: What is causing sticking valve?

Q: In 2004, I bought a Lycoming O-320 D1A, via Van’s, and started flying it in January 2005 in a RV-9A. I broke it in according to the instructions (75% or more until oil consumption stabilized). In spite of having an oil filter I always do oil changes at about 30 hour intervals. All through the life of the engine it has used 100LL and the average power (after break in) can be estimated from the fuel consumptions of 5.9 to 6.1 max gph. Cylinder head temperatures during takeoff remain below 400°F on a calibrated (boiling water) steam gauge and at about 350°F in cruise.

In April 2010, at 676 hours, I had a sticking valve. Curiously this manifested itself not at cold start-up but during takeoff.

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Ask Paul: What are these aluminum specks?


Q: I lost the left mag on my O-540. When I took it apart, I found four aluminum specks in the top oil screen. I pulled the rear housing off and found the aluminum gear still in the engine. I sent it off for repairs to Tulsa, where they installed a new oil pump, shaft, gears and housing, as well as a new fuel pump and dry vaccum, and two rebuilt mags. I ran it for 1.5 hours, then pulled the screen and found a few specks again, but not as many as the first. Any ideas?

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Ask Paul: What’s the best engine for my Pacer?


Q: I plan to install an 0-360 with a constant speed prop in my Pacer, replacing my 0-320-A1A. I have a couple of engine choices under STCs, including the 0-360-C1A. I am looking for the lightest engine. Was this made as a narrow deck engine? If so, what serial numbers were narrow decks? Also, I cannot find the dry weight difference between this and my current engine, which is a narrow deck engine. Is this information available? Are there any concerns with hollow crankshafts?


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Ask Paul: What to do about oil-fouled plugs?


Q: My partner, Lou, and I just had our Piper PA 28 235 overhauled and are having problems with the lower plugs getting oil fouled. The plugs have been cleaned a couple of times but she runs rough and they foul again. The mechanics are talking about putting a thin wire plug in. My concern is that we could have a leak in the valve stem seal, rings, or head or valve cover gaskets. The cylinders were rechromed and we had new rings, the valves machined, etc. One shop did the machining and cylinders, another shop assembled everything.

Where should we start?

TOM CAMP, via email

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Ask Paul: What’s going on with my spark plugs?


Q: I have a 1962 Piper Cherokee 160 with the O-320-D2A engine. The engine had a complete overhaul in 1992 and only 500 SMOH. In addition, 20 hours ago the engine had an annual in which an oil change was done, new plugs, and compressions in the 78/80 range.

What I have noticed is when I taxi the airplane without flying it (I always lean on taxi), the next time I do a run-up the left mag performs poorly and I have to lean and “burn off” whatever is getting on the plug(s), then the airplane runs fine. This has happened to me twice recently. [Read more…]