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?

STEVE ADAMS,Seattle

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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...]

How to break-in your engine

I recently received a letter asking about engine break-in following overhaul. This is a subject that should be of interest to everyone, even though you may never actually have the opportunity to break-in an engine during your flying years.

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The importance of keeping current

Q: I have a Glasair with a Lycoming IO-360-B1E engine. After reading your article in the May 11 issue, I tried to get a copy of Lycoming’s SI1325A to see if I should change the timing from 25 to 20 degrees BTDC, but was not able to find that instruction. Can you help?

RON WALTERS, via email

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Ask Paul: Too much information about our engines?

Q: I have a factory reman Lycoming O-540 E4B5 with 300 hours and 2.5 years on it. At idle (1,000 rpm), my JPI is showing alarms on the #1 EGT for having a large differential — #1 EGT is only 600° while the rest are 1,200-1,300°. Above 1,500 rpm and higher everything seems fine with normal readings and maybe #1 CHT a little lower, but I expect that since it is first in the airstream. I have full data printouts from the JPI.

I have checked the plugs even though my mag checks are fine and replaced the probe on #1 EGT with no change. I’m scared to think I have stuck valves. [Read more...]

The marriage between piston rings and cylinder wall

Q: I am an A&P, and have been in aviation since 1990. I once worked with another mechanic who told me that if you pull a piston out of a cylinder, you must replace the rings and hone the cylinder. He is the only tech I have heard say this — until I read your article What’s best? A flush or overhaul?

You stated: “If oil starvation is suspected, you may want to remove the #1 cylinder (leave the piston in the cylinder so you don’t have to hone the cylinder and install new rings) and remove the connecting rod from the crankshaft.” Can you explain this? Is there a Service Bulletin or other directive that explains this practice? Thanks for sharing your knowledge with us.

TOM THROSSEL, via email

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Will this replacement camshaft work in my engine?

Q: I have an O-290-D2 that I am going to use in an Experimental Wag Aero 2+2 that I am building. Although the engine was flying regularly before I removed it from a Pacer and pickled it, I want to open it up to look at the cam. If the cam is pitted, a replacement will be difficult or prohibitively expensive.

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Ask Paul: What causes this popping sound?

Q: I am test flying my new RV-9. It has a new Superior O-320, dual p-mags and an MTV11 2-blade MT prop. When it has been running at cruise power for a few minutes or more (say 2,300 rpm x 23 inches or more) and then I reduce the throttle, I get a popping/crackling sound from the engine. If I reduce the rmp before pulling the throttle, it doesn’t seem to do it so much. This typically happens when joining downwind to land, but other times too if I pull the throttle.

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Ask Paul: What’s best? A flush or overhaul?

Q: I recently found paper towel bits and pieces in a Lycoming engine in an aerobatic airplane. The pilot said he saw the oil pressure go to “zero,” so he reduced power, and landed safely. Would you suggest a flush or overhaul? What’s the best way to go about this?

ED NELSON, via email

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