What’s causing Mooney’s rough-running engine?

Q: I bought an older Mooney with a Lycoming IO-360 with Bendix fuel servo. The engine starts to run rough once the last 1/2 inch of throttle is given. An induction leak cannot be located. Would a faulty sniffle valve be to blame? Any other possibilities?

JAMIE RICHARDS

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Does flight school’s 172 need new rings?

This question was initially sent to our fuels and oil expert Ben Visser, who passed it on to our engines expert Paul McBride for further comment.

Q: Our flight school has a Cessna 172N with an O-320 H2AD. The engine was rebuilt 120 hours ago after cam/lifter failure. The engine uses one half quart of Aeroshell 100 Plus every hour! Oil analysis iron ppm is very low. Compression was 75-78 at 100 hour. Do you think that the rings did not seat? Do I pull the cylinders for new rings and hone?

Denney Marsh, Hemet-Ryan Flight School 

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Ask Paul: Upgrading to a wide deck engine

Q: I read your article from the Oct .7, 2009, issue of General Aviation News on Wide Deck vs. Narrow Deck Lycomings with great interest. I am trying to figure out one detail that I think your article answers, but I just want to make sure.

I have a 1960 PA-22 Tripacer that originally came with a 150-hp O-320-A2B ND engine. It is ready for a major overhaul, and my IA recommends that I upgrade to a WD O-320-B2B engine.

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Ask Paul: The Cherokee Rattle

Q: I just bought a 1974 300-hp Cherokee Six. It has about 1,200 hours to run, has great oil pressure, good compressions, hardly uses oil, no metal in the filter, but during the run-up at 2,000 rpm, the engine makes quite a deep knock.

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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?

GREG KNEELAND

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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: Why is my Beagle Pup such a pig to start?

Q: I have a Beagle Pup 150 (the father of the Scottish Aviation Bull Dog) fitted with a Lycoming O-320 engine. When the weather is cold — in the UK this is anything less than 5° C — it has become an absolute pig to start, but once started it runs perfectly.

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Ask Paul: Why are my #3 cylinder CHTs so high?

Q: Recently — 50 hours ago — I had a Lycoming O-360-A4A overhauled with new ECi Titan steel cylinders installed. The #3 cylinder has had high-ish CHTs from the beginning. [Read more...]

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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