02-13
In part one of my Insight engine monitor pirep (Piper Flyer, January 2013), I described the G3 engine monitor’s operation and its diagnostic and data logging capabilities.
This month, I’ll focus on how the G3 engine monitor got installed, along with how the 22 sensor leads were wired in order to make all those features light up on the liquid crystal display.
The journey starts with configuring the G3 monitor to fit your aircraft.
Custom Design
Insight does not have a one-size-fits-all approach to engine monitor configuration, which is readily apparent from the beginning: the company’s website includes a separate order form for each G series model.
I ordered the G3 instrument, and this form featured lots of additional questions to properly configure such a full-function engine monitor. The first six sections were straightforward and asked for owner and installer contact information. The remaining questions involved details about aircraft make, model and year; engine make and model; buss voltage; plus specific sensor type and size information.
The website describes and shows pictures of these sensors and how to select the sensor for your aircraft. The fuel flow sensor selection highlights an important difference between aircraft: fuel flow sensor options vary for fuel injection versus carburetor installations and mounting locations. Prior planning for necessary AN fittings to insert the sensor in the fuel line will help the project go smoothly later on.
Insight’s technical support is available when questions come up. They will assist with selecting the correct configurations and discuss installation options with you.
For example, I wasn’t sure whether or not to keep the OEM carburetor air temperature gauge. At first I thought I wanted to keep the 2 ¼-inch gauge, but after giving it some thought, I decided the best course of action was to remove the OEM gauge and use the Insight carb air temp, which is logged on the SD memory card. (For more information, take a look at the “Why is That?” section in Part 1. There I discuss how logging this variable helped me find the best temperature to improve fuel air distribution.) Sometimes it’s hard to let go of something that is old and familiar, but moving on was the right decision.
Each harness and cable on the engine monitor is designed to fit a specific model aircraft and engine configuration. The typical aircraft harness is an eight-foot-long CHT and EGT thermocouple harness, but a 10-foot harness is required for, say, a Piper Saratoga with a forward baggage compartment between the engine and instrument panel. This is just part of why the order form is so comprehensive.
Other considerations include the following: Does your engine have fuel injection or a carburetor? Do you have one or two turbochargers in your aircraft? The kit you’ll receive—with all the sensor inputs and monitor microprocessor programming configurations—is specialized for your aircraft and its engine.
Documentation
The installation manual, pilot’s manual and STCs for both Transport Canada and FAA arrived in a small box along with a lot of plastic bags filled with all kinds of good stuff (see Figure 01, page X).
The first item on top was the packing list: it listed the quantity and serial numbers for each item. The installation manual was comprehensive and full of cautions on how to route thermocouple harnesses and pulse transmitting wiring. (The long and short of it is to keep them away from each other to ensure noise-free data sensing.)
The manual, titled “G Series Pilot’s Guide,” is an indispensable document for initial instrument training. Along with many other avionics manuals, I now keep an electronic copy of this guidebook in the Documents window in ForeFlight. With this method, my most-used documents are always readily available to me and I do not need to carry a lot of bulky paper.
Installation
Twenty-two input sensors and an output to the Garmin datalink made this installation a complex project. Laying out all the sensors, wiring and monitor completely covered the workbench! (See Figure 01, page X.)
I worked under the supervision of Dave, my local A&P/IA, to install the G3 in an owner-assisted capacity.
My hours are not a true measure for an experienced shop installation. To get an estimate for installation cost, first talk to your local maintenance facility. Estimates will vary depending on how much experience your shop has installing monitors and whether there will be panel modifications for the display installation. Don’t be afraid to seek a second opinion from another facility.
Installing the (EGT) thermocouples means more than just drilling a hole in the six exhaust stacks. The first EGT location decision is deciding on the uniform distance from the cylinder heads. Thermocouple placement on the exhaust stack is important to maintain a safe distance from the spark plug lead. Routing all these sensor leads takes time to ensure you are staying away from sharp bends, electrical pulses and hot spots.
You may be tempted to trim these thermocouple leads to an exact length, however, Insight recommends leaving them intact. The reason is the thermocouple analysis function display used to confirm thermocouple integrity assumes a specific resistance per foot to analyze thermocouple degradation. (Another good reason to leave extra wiring is in case you want to move the analyzer to another panel location.)
Figure 02 (page X) shows all these sensor leads before tie wrapping and coiling the excess length in place.
The final step in wire routing is deciding where to go through the firewall and how to coil the excess wiring length.
The oil temperature probe location required learning more about oil flow within the engine. In the more popular models of Continental and Lycoming engines, the oil pump draws hot oil from the sump and under pressure the flow proceeds up the right side of the case (as viewed from the engine rear). At the front of the case the oil crosses over the left side and returns to the rear of the case. The key to good readings is selecting a probe location in the oil stream before the oil cooler.
In this installation the oil temperature probe’s first location was on the oil cooler outlet. This location only informed the G3 that the cooler efficiently cooled the oil under all conditions. The temperature reading here was 130 to 140 degrees F—quite a different number than what the OEM gauge had shown. Dave and I wondered how this could be, and started to investigate.
Looking along the right side of the case revealed a 3/8-inch opening under the right mid/number three cylinder (see Figure 03, page X). Placing a telephone call to Continental confirmed that this 1/8-inch pipe thread opening was into the oil supply hot side, just prior the OEM oil temperature location. Situating the sensor in this location showed a normal 200 degree F oil temperature.
There are also two additional oil probe locations on the right rear of the case that are typically just aft of the engine shroud.
If you have any doubts about where to locate the oil temperature probe, call Continental’s or Lycoming’s technical support, and be ready with your engine and aircraft details—and your specific questions. (See Resources at the end of this article for manufacturers’ contact information. —Ed.) They can advise you about locations for your G3 oil temperature probe.
The instrument panel in my aircraft was already fairly crowded with multiple 2 ¼-inch openings, all already full with useful information. Dave and I chose to situate the Insight monitor high on the left panel, close to the pilot’s line of sight for normal flying operations (Figure 04, page X). Mounting the Insight instrument in the far right panel, we determined, would only diminish its utility and value because it would be so far away from a pilot’s typical instrument scan.
Conclusions
Insight’s ordering process is well done, and its product documentation is complete. Except for those fuel flow AN fittings, all that is left for you to do is to take you time to plan and install your G3 Engine Monitor so you can enjoy the results of significantly better engine operating information.
The Insight G3’s leading-edge diagnostic technology help to justify this system’s purchase and installation cost. The G3 provides you with confidence about your engine’s proper operation and may assist with early detection of problem. When compared against the cost of a new engine or a rebuild, knowing there is an issue before you exceed critical engine parameters may save you quite a bit in the long-term.
Charles Lloyd has logged 10,000 hours since his first flying lesson in 1954. He worked for Cessna Aircraft for 16 years, and retired as captain for a major fractional aircraft ownership company. His personal aircraft is a great business tool for his real estate investment company. Send questions or comments to editor@www.piperflyer.com.
Resources
Insight Instrument Corp.
P.O. Box 194
Buffalo, NY 14205-0194
(905) 871-0733
Insight’s Price Book
(For all G Series monitors)
insightavionics.com/pdf files/Insight Price.pdf
Continental Motors, Inc.
Technical Support
(888) 826-5465
(251) 436-8299
continentalmotors.aero/contact.aspx
Lycoming Engines, a division of Avco Corp.
Technical Support
(800) 258-3279
(570) 323-6181
lycoming.com/utility/contact-us.html
