Should I pull the cylinders in my Pitts?

Q: I just bought back my original Pitts Special after 41 years. It now has a narrow deck O-360 that hasn’t been run in four years. I’m getting the PS-5C overhauled, but wonder what you think about pulling cylinders to inspect the camshaft before running it. We borescoped the cylinder walls and there appeared to be a honey-colored film on various areas. [Read more…]

Ask Paul: Does glazing mean cylinders must be honed?

Q: I am in the process of acquiring a Piper Seneca equipped with twin Continental TSIO-360-RB engines. Both engines have about 450 hours to go before overhaul.

The aircraft was last flown approximately three years ago. Technicians maintain that the cylinders have to be honed due to glazing as a result of the time elapsed since the last engine run. [Read more…]

What’s fueling higher engine temps?

Q: I own a factory overhauled O-360 A4A, which I’ve owned since it left the factory. I’ve flown behind it for 600 hours. I recently had a prop strike and the engine was stripped and reassembled with no damage found. All they replaced were the exhaust valve guides and piston rings. (And all the rest as per shock load spec.)

The plane has been put together exactly as before and performs almost better than before. I have 10 years of multi probe engine monitor data to compare. [Read more…]

How extensive an inspection does my engine need?


Q: I have 210 hours on my engine, which was overhauled in November 2009 at 3,288 hours. Five of the eight studs are now broken on cylinder #3.

The motor had only a slight vibration during the last 3/10ths of an hour before discovering the broken studs.

I would appreciate your input as to how extensive an inspection should be made. Have you had experience with such an occurrence? [Read more…]

What’s causing a constant roughness in my engine?

1961 Piper PA-24-250 Comanche. Photo by D. Miller.

Q: I own a 1963 PA24-250 Comanche. Over the past two years I have replaced all six cylinders, both mags, harnesses, primer lines, new fine wire plugs, fuel lines, engine fuel pump, both electric boost pumps, and I am baffled. During cruise settings at 2,400 rpm and 23 inches of manifold pressure, my engine still feels as if I’m flying in rough air. There’s a constant roughness that is minor in nature, but still there. [Read more…]

One engine, many questions

Could the Cessna 172 someday be a technological mystery?

Q: I have a Cessna 172N with the Lycoming O-320-H2AD 76 series engine, serial number L-3406-76. I’m trying to sell it, and I’m getting all kinds of questions regarding the “A” suffix, the “T” mod, and others that are way too far out there to even mention. [Read more…]

What is causing bent rods and sticking valves?

Q: I am acquainted with two IO-540 engines with 1,000-plus hours that have bent rods in the #5 cylinder and stuck valves in the #2 cylinder. One aircraft was manufactured in 2007 and the other in 2009. The oil has always been changed at 50 hours using Exxon Elite 20/50. Any particular thoughts?


[Read more…]

Time for an overhaul or just keep flying?

Q: I have a ’69 Skyhawk with 2,500 hours on the engine. Good compression, no metal, one quart oil burn every eight hours. Should I get a top overhaul or a complete engine overhaul or just keep flying until an indication of a problem?

TED HALL, Upperco, Md.

A: Well, I must tell you that with 2,500 hours of operation since 1969, this engine certainly doesn’t owe you anything! If this is the original engine in this aircraft and after providing you reliable service for 45 years, I’d say you got your money’s worth.

[Read more…]