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 PA32R(T) Overhaul Considerations – Part I

 

February 2002

When I was first involved in general aviation with my A&P license in 1978, I did warranty work on new T-tail Turbo Lances and later, in the ‘80s, the early Turbo Saratogas. Recently, I did an R&R on an engine for overhaul; a T-tail Turbo Lance (PA32RT 300T) that I had worked on when it was new in 1979. This article will detail the expenses and some dos and don’ts for this type of job. If you own or are in the market for this aircraft or an early style Saratoga and the engine is near TBO, you’ll want to read this article very carefully. I believe you will be as surprised as I was at the costs involved.

 

In all high-powered aircraft engines, heat is the enemy of reliability. This is true for this series and especially for the turbocharged versions. Close attention to heat control and management is the watchword here - close attention.

 

The PA32RT 300T and early Sartogas are very recognizable by the large shark-like opening on the bottom cowl and the louvers that are installed across each side of the top cowl. Their TIO540 S1AD engine has a manual waste gate linked directly to the throttle via a cable. As the throttle is advanced, the waste gate for the turbo system is closed. There is a specific rigging ratio between the throttle and the waste gate. At full throttle, the waste gate should close to a gap of about 1/8".

 

An interesting feature about this engine is the updraft air-cooling. Cooling air comes in the front of the cowling at the bottom on the engine, is then forced up through the cylinders, past the intake tubes and over the top of the engine to where the exhaust system is installed. The cooling air then goes across the exhaust stacks (which are above the cylinders), over the back of the top of the engine and down through all the accessories (magneto, fuel pump, and vacuum pump) and exits aft via the cowl flaps. This routing generates a tremendous amount of heat on these accessories. That is why the magneto has a heat blanket wrapped around it and the vacuum pump has a shroud with fresh air hoses to keep it cool. The fuel pump also has its own heat shroud and fresh air hoses.

 

Ever since Piper came out with the PA32RT 300T, there have been corrosion problems on the engine mount. Heat radiates from the turbocharger, the waste gate collector pipes and the exhaust system. The engine mount and tubular turbocharger mount corrode easily with the resulting high surface temperatures.

 

When we pulled this engine (a first-run engine with 1700 hours total time) the engine mount tubes, which run near the turbo and across the back to where the exhaust system crosses over, were pitted so badly that they had to be replaced. The horseshoe assembly that attaches the turbo to the engine was also so worn down from exhaust erosion that it had to be replaced along with three tubes of the engine mount.

 

Over the years, attempts to solve the erosion problem have mostly failed; epoxy paint, for instance. However, one solution seems to work reliably. The engine mount was sent to Kasola & Associates; a firm I have utilized before. They recommend a powder coating used on Indy car exhaust systems, which is made to continuously withstand 2000º F. After the engine mount was repaired and the turbocharger horseshoe was replaced, everything was coated with this special powder (which is available in any color, as long as it is flat black). The $250 or so spent on the coating would have prevented the $2,600 spent on the repair plus the cost of removing and shipping the engine mount.

 

Proper hoses for the fuel and oil systems are critical since they are located at the back of the engine; the path for the heat from the cylinders and exhaust stacks. I only recommend 124H Stratoflex Teflon fire sleeved hoses. They are expensive but will give you long service life and peace of mind. The most critical hose supplies oil to the turbocharger and runs between the waste gate collector inlets for the right and left exhaust banks. Expect to spend $1200 to $1500 for just the hoses. Again, that does not include your mechanic’s labor.

 

Depending on its condition, the turbocharger itself will cost $900 to $1200 for an overhaul by a quality shop. This does not include the inlet check valve, which looks similar to an AN4 fitting. A new check valve ($600) is the only option since it’s a sealed unit. Another expensive item is the cable rod end that attaches to the waste gate. It becomes worn out from the intense heat in proximity of the waste gate. This tiny rod end costs over $550. If you must replace the entire waste gate, Lycoming will sell it for $3,700, but it includes the rod end.

 

A prop governor, vacuum pump and alternator are some of the items not included with your overhauled engine, but it will have a Prestolite field coil type starter. These field coil type starters are obsolete; just install a new Sky Tech permanent magnet starter. Not only will you save 8 to 10 pounds at the front of the engine, but your engine will turn over twice as fast as with the Prestolite. Hot starts should become a thing of the past and at $400 to $450, it is a worthy investment.

 

A new vacuum pump is necessary if you fly IFR. I never ever install rebuilt vacuum pumps on any of my customers’ planes. I don’t believe they are worth the money saved. A new vacuum pump will cost $400 to $500, but should provide over 800 safe IFR hours. Most of these Pipers run both gyros from the single vacuum pump, so it is important that it be reliable, i.e. new.

 

The Bendix D2000 (or D3000 on later models) dual magneto is critical on this installation. Wrapped around it is a heat blanket, which must be in good condition. If any portion is missing, replace it. Piper sells new blankets for about $100. Make sure that the magneto is overhauled by a reputable shop and not one that does assembly line mass overhauls. I have used Aero Mag in Southern California for over twenty years; they do magnetos one at a time. Because of the heat that the accessories are exposed to, this magneto must be removed every 500 hours and sent in for a 500-hour service and inspection.

 

The prop governor should have the flyweight assembly replaced if it is not a first-run governor, $900 to $1100. While the engine is off, re-glue all the loose heat shield material on the firewall and top cowl. If your engine is a first-run, you may have a reputable overhaul shop do the overhaul. I only recommend new Lycoming cylinder assemblies for this engine. Don’t use Cerminil or chromed cylinders. New Lycoming cylinders are the best for oil consumption during break-in and longevity of your engine and they will run the coolest. Cerminil or Cermichrome cylinders will run hotter, so I don’t recommended them for any turbocharged engine.

 

Look at Lycoming service instruction 1014M. In 1996, Lycoming decided that all turbocharged engines should be broken in with detergent oil, not mineral oil. For over thirty years, Lycoming said break-in for turbo engines was to be done with mineral oil. My question to Lycoming is “why change now?” Were they wrong for the last thirty years? Their reasoning is that detergent oil will suspend the particles of metal, dirt, and what ever else may be running around in the engine during break-in, get them to the filter and not get stuck in the turbo bearing. For over twenty years, every turbocharged Lycoming engine break-in with mineral oil has worked for me with no problems as long as new Lycoming cylinders are used. Moreover, oil consumption over the life of the cylinders is significantly reduced. So take service instruction 1014M with a grain of salt and don’t believe every thing that the manufacture writes.

 

A good reputable shop will charge you anywhere between $30,000 and $45,000 to overhaul this engine. By the time you do the other things in this article you will add another $15,000 to $20,000 on top of the engine overhaul price. Better plan on $45,000 to $65,000 for the whole job.

 

Make sure that when you put your engine back in with all these new parts that you don’t install the propeller with the old dirty oil in it. Send your prop out to have it flushed and cleaned if it has less than 500 hours since overhaul. If more than 500 hours or five years since overhaul, bite the bullet and get the prop overhauled. One last item, remember to replace the entire rubber engine baffling and always install new rubber engine mounts.

 

After an engine or prop installation have a dynamic balance performed. This makes a huge difference on this installation. Be careful when dynamic balancing this propeller; only utilize the placement for existing Hartzell weights. If washers need to be added for fine-tuning, install them where the Hartzell weights would normally be. You can use the flywheel, it has holes drilled all the way around it to install washers, but be certain that any bolt installed does not catch the starter. Never, never, never drill a hole in the back plate of the spinner to install a screw, nut and washers to balance these engines. The hole will eventually crack out due to centrifugal force requiring purchase of a new spinner bulkhead and possibly a new spinner. Always install weights at the locations the manufacturers have established or use a good secure location such as the flywheel.

 

Part 2 of this article will discuss the high points of doing an annual on the PA32R series airplanes. If you have any question or comments on this article, e-mail me or contact me at my aircraft repair shop at: 307-789-6866. Until then, enjoy flying your Piper.

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