November 2014-
Q: Hi Steve,
I noticed that last month you answered a question about preserving an engine when an owner isn’t going to fly for a while. I wish I had read your article earlier because I didn’t do anything except park my plane in my hangar nine months ago.
It’s a long story (and a much too personal one to write about in an airplane magazine!) but now everything has gotten straightened out. I again have the time and the desire to start flying my sweet 1960 Piper Tri-Pacer Caribbean.
A lot of people call the Tri-Pacer names, but it will do everything a Cessna 172 will do performance-wise. What do you recommend I do to the engine to get it up and flying again?
—Tri-Pacer Tommy
A: Dear Tommy,
It’s always good to hear from a member that loves his or her airplane. The 1960 Tri-Pacers came from the Piper factory with either a 150 or a 160 hp engine; earlier Tri-Pacers were powered by a 135 hp engine. The procedure for returning any of these engines to service is the same.
Ideally, you had just changed the oil and flown only a few hours prior to stopping flying. New, fresh oil does a good job of protecting steel parts; oil that isn’t changed regularly will eventually become acidic.
Today’s oils contain additive packages designed to combat the formation of these engine-eating acids, but eventually the additives are neutralized. One engine expert suggests that these packages only last 20 to 30 hours, depending on the health of the engine and the pilot’s operating practices.
The steps I recommend to start flying this engine again are to change the oil and filter. Then remove one spark plug from each cylinder and squirt a couple of ounces of warmed-up engine oil in each cylinder.
After oil has been squirted in all four cylinders, pull the prop through by hand (make sure the magneto switch is OFF) for eight pulls. This helps lube the cylinder walls and rings.
Then use the starter to spin the engine for a couple of 30-second cycles. Let the starter rest for five minutes between runs.
You should see the needle or readout of the oil pressure (OP) gauge indicate pressure during the starter spinning cycle. This proves that the oil pump is primed and is pumping oil. No movement? Continue the starter spinning cycles until you see movement on the OP gauge.
Drain all the fuel sumps and the strainer to make sure that there’s no water or sediment in the fuel system. I recommend that you drain at least a quart out of each tank. Now is the ideal time to find the water or crud, not after you lift off the runway.
When the sumps run clean, then I would reinstall and tighten the spark plugs to the correct torque. Install the plug wires.
Chock the wheels, and—with a fire extinguisher handy—go through your normal procedure to start the engine. It should fire off. When it fires, idle it at 1,200 rpm and check for oil pressure.
Run it for a couple of minutes at 1,200 rpm. Switch from “both” to “L” and back to “both;” then to “R” and back to “both.” You should get a mild rpm drop. If the engine quits on “L” or “R,” you have a dead magneto. Get it fixed prior to the next step.
The next step is a thorough inspection of the engine and cowling for fuel and/or oil leaks. When that’s complete (and any leaks have been sealed), taxi your Tri-Pacer over to the fuel island and add some fresh fuel if there’s room in the tanks. Avgas is laced with stabilizers but fresh is always best.
After fueling, taxi out. Facing into the wind, perform the normal pre-takeoff runup. If everything is in the green during the normal pre-takeoff runup, go flying. If you can, use the longest runway on the airport.
Don’t baby your engine during this process—go ahead and push the throttle in; you won’t be hurting anything as long as the engine is running smoothly.
I’d recommend staying within gliding distance to the airport for at least the first 15 minutes of flight.
I suspect your engine will act a little wonky for the first few hours. It might use a little more fuel and oil than you’re used to. As long as it’s running smoothly, it should soon normalize as the clean oil circulates.
Since there may be more blow-by of combustion gases and unburned fuel during this return-to-service operation, I recommend that you again change the oil at the 10-hour mark.
Lycoming engines are built with the camshaft and lifters at the uppermost part of the engine. Therefore it’s these highly stressed parts that are most often affected by rust due to lack of lubrication during periods of inactivity.
Unless an engine has been “pickled,” as discussed in the October 2014 Questions and Answers column in Piper Flyer, there’s nothing that can be done after a period of inactivity to ensure the cam and lifters haven’t rusted.
Just follow these return-to-service procedures, keep those fingers crossed… and keep flying.
Q: Hi Steve,
My partner was flying along in our 1971 PA-28R-200 Arrow II last week when he lost the vacuum pump. Gyro instruments spun down and vacuum gauge went to zero. Fortunately, he was VFR.
Today our mechanic called to suggest that we send both the directional gyro and the artificial horizon instruments in to get checked for carbon contamination. Is this legit?
—Gyro Gary
A: Dear Gary,
Yes, it’s legit. Here’s why. During flight, ram air produces a slightly positive pressure under the cowling. The engine-mounted pump of the instrument pneumatic system on your Arrow draws cabin air through a filter, then through the two gyro instruments and through a vacuum regulator valve. This produces a negative pressure (vacuum) in the pump, tubing and instruments.
Most vacuum pumps are dry-style pumps which use rotating vanes of carbon for internal lubrication. During the most common pump failure the vanes disintegrate, causing a loss of the negative pressure between the pump and the instruments. The positive pressure under the cowling rushes into the system through the pump, picking up carbon dust and vane parts. This residue usually ends up in the gyros.
A properly installed Clear View inline filter by Aerotech Components traps this carbon in the event of a pump failure. As seen in the drawings, the Clear View filter is installed in the hose between the vacuum pump and the vacuum regulator valve.
The CV1J4-P filter is approved for installation by STC on your Arrow and on many other GA airplanes. This filter costs right around $100, but it will sure save time and money if your dry vacuum pump ever fails.
Happy flying.
Know your FAR/AIM and check
with your mechanic before starting
any work.
Steve Ells has been an A&P/IA for 43 years and is a commercial pilot with instrument and multi-engine ratings. Ells also loves utility and bush-style airplanes and operations. He’s a former tech rep and editor for Cessna Pilots Association and served as associate editor for AOPA Pilot until 2008. Ells is the owner of Ells Aviation (EllsAviation.com) and the proud owner of a 1960 Piper Comanche. He lives in Paso Robles, Calif. with his wife Audrey. Send questions and comments to editor@www.piperflyer.com.
RESOURCES >>>>>
“Pickling a Cherokee 235” by Steve Ells
Questions and Answers, October 2014
www.piperflyer.com
Clear View inline filter
Aerotech Components, Inc.
aerotechcomponents.com
