Installation manual

GEM INSTALLATION MANUAL DOCUMENT No. 070906 REV. 1.4
INSIGHT
INSTRUMENT CORP. 12 BOX 122, FORT ERIE, ONTARIO, L2A 5M6
The Spark Plug Gasket must be removed and replaced by the Gasket Probe. Annealing of the Gasket Probe is
not required or recommended, and the Gasket Probe Does Not require replacement when the spark plugs are
changed.
Alternatively, an Adapter Probe may be used instead of a Gasket Probe. An adapter probe will allow both
displays to derive their CHT readings from the same thermo-well. For this reason, use of the Adapter Probe is
recommended instead of a Gasket Probe.
If the factory-installed CHT display has a bayonet-style probe, the Insight Bayonet Adapter Probe (2855) may
be used instead of the Gasket Probe.
The Bayonet Adapter Probe replaces the original bayonet adapter. It has a screwdriver slot to facilitate
tightening in place, and placing a drop of non-seizing lubricant on the threads before installation will ease
installation and subsequent removal.
Once the Bayonet Adapter Probe has been installed, the original bayonet probe maybe locked in place with a
push and a twist.
If the factory-installed CHT display has a threaded probe located in the thermo-well, the Insight Threaded
Adapter Probe (2856) may be used. The Threaded Adapter Probe is installed in the thermo-well between the
cylinder head and the original CHT probe.
Installing the Carburetor Temperature Probe
The GEM is supplementary for carburetor temperature. Install the Insight Carburetor Temperature probe
(Insight P/N 610C-021) into a 1/4-28 tapped hole in the carburetor. Many carburetors have an existing hole for
this purpose but it may be plugged and require drilling or tapping. Consult with the engine or carburetor
manufacturer to determine the probe-hole location. Ensure the probe does not interfere with any internal
carburetor components.
For G2, G3 and G4 GEMs refer to Drawing 610C-315 or G4-315 for electrical connections. The G1 GEM uses
pin numbers "A" and "1" on the P1 Edge-Connector. In the case of upgrading from an older GEM system to a G1
GEM check for the possibility of existing wiring to the "A" or "1" pins on the P1 connector. Remove any existing
connections to these pins and only connect the Insight Carburetor Probe. See Wiring Diagram Drawing 1200-018
Rev. E or later.
Installing The Turbine Inlet Temperature Probes
There are several types of Turbine Inlet Temperature (TIT) probes that can be used with the GEM system.
· Clamp-Type TIT Probe (P/N 2871) or Dual TIT Probe (P/N 4871) - is identical to the EGT probe
except that the clamp diameter is larger.
·Threaded-Type, (7/16-20) TIT Probe, including a weld-on boss (P/N 2872) or Dual TIT Probe (P/N 4872).
·Threaded-Type, (1/4 NPT) TIT Probe (P/N 2873) or Dual TIT Probe (P/N 4873).
The dual-type probes have two thermocouples, with separate signal outputs to drive two instruments.
For aircraft with a threaded fitting boss already welded to the turbine inlet, the two threaded type probes are
used - part number 2872 (7/16”-20 Thread) and part number 2873 (1/4 NPT Thread), as applicable. The 2872
Threaded fitting can be installed on any aircraft when a more permanent installation is desired, or when space
for the clamp-type probe is limited.