J.P. Instruments Classic Scanner - Manual (Page 2)

INSTALLING THE EGT SCANNER
Page 2 of 2
Rev-D
1) Exhaust Gas Temperature Probe (EGT)
The Model M-111 Probe will fit any existing holes in the exhaust stack in any engine having the
diameter of 1/8" to 1/4". If no hole exists, it will require the drilling of a 1/8" diameter hole and
ream to fit. It is important that each probe is mounted a uniform distance from the exhaust stack
flange. A nominal distance of 2 to 4 inches from the flange is recommended. (see fig-4). If the
recommended distance is impractical because of obstructions, slip joints or bends in the
exhaust system then position the probes a uniform distance from the flange where space
permits. Be certain to locate all holes BEFORE drilling to ensure that nothing interferes with the
probe, clamp, clamp screw or wire. Careful matching of probe position will provide best
temperature readings. Radial engines like Pratt & Whitney / Wasp should place the probes in
the interconnecting exhaust stack (which is approximately 4 inches long) between the
exhaust flange and the exhaust accumulator.
Insert the probe in the exhaust or previously drilled hole (see fig-5) so that the tip of the probe is
in the center of the exhaust stream, and tighten the stainless steel clamp to a torque of 45
in/lbs.. Cut off the excess strap close to the screw.
2) Turbine Inlet Temperature Probe (TIT)
The standard TIT probe PIN M-111-T with a special clamp is placed in the exhaust stack
accumulator to a maximum depth of 1/2 inch and approximately four (4) inches from the Turbine
inlet if possible, on the waste gate side of the turbine. TIT will appear as EGT probe # 7 on six
cylinder engines and as EGT probe #5 on four cylinder engines.
3) Cylinder Head Temperature Probe (CHT), Bayonet
Bayonet probe 5050-T has the adapter or threaded section as part of the probe. The bayonet
probe has a screwdriver slot to facilitate tightening A drop of lubricant on the threads before
installation will help.
NOTE:
Required original equipment that is Red Lined may not be replaced by the SCANNER TIT or
CHT installation. This includes but is not limited to all aircraft with adjustable cowl flaps and on
aircraft with placards on the instrument panel showing a climb air speed, for cooling, different
from the best rate of climb air speed.
If a previously installed TIT, CHT or EGT is listed on the aircraft equipment list as Optional
Equipment or not listed at all, it may be replaced by the EGT/CHT SCANNER. AC NO: 20-41A,
Date 4/5/77, Subject: Substitute Technical Standard Order (TSO) Aircraft Equipment. This
Advisory Circular states that TSO'd equipment may replace TSO'd Equipment. Copy available
at JPI.