Source
http://www.oregonaircraftdesign.com/files/129360587.pdfThis is what the AP mechanic I bought my hirth from said to check out.
How to tell if you are getting correct engine
instrument readings
It's always a good idea to check that your probes and instrument are reading properly
before installation or when you get an odd reading. Sometimes folks assume they need
to start messing with carburation when that's not the problem.
Note that Rotax 2
-
cycl
e engines with stock OEM crankshaft seals often leak after 5 to 6
years or around 300 hours run time. This can cause air leakage and increase EGT
readings which can lead to a lot of engine damage real fast.
Before attaching the probes to the engine, use a
jumper cable to ground it to the
engine and connect the other leads to the instrument.
For the EGT probe, use the very tip of a paraffin candle flame (birthday candle) which
should read 932 F. If using an analog type gauge, the probe may need to be heated
with a propane torch to get it off the 0.
The temps probably won't be exactly 932 F but + or
-
about 50 F is close enough and
it's nice when both probes are pretty even.
For the CHT, water temp and oil temp probes, determine the boiling temp of water at
yo
ur elevation and use a cut down pop can, vice grips and a propane torch. Take the
reading right when it starts to bubble as it will rise 20 F to 30 F if let to hard boil.
If you have 2 of the same probes and find an odd temp reading on one, the leads can
b
e swapped at the instrument to determine if it's the probe or the instrument.
For a static RPM check (tied down, brakes on and throttles rigged correctly) use a
hand
-
held tach that counts the blades. If using a gear reduction, multiply the RPM
times the re
duction ratio.
Oftentimes I find that especially the analog gauges give faulty readings. I much prefer
the digital type and the best value available as of this writing is the MGL E
-
1 engine
monitor. Below is a description and current pricing. Let us know i
f you need one!
The E1 universal engine monitor combines in one compact 3 1/8" format instrument all
that is needed to monitor most smaller aircraft engines, from two
-
stroke ultralight
engines to medium sized four strokes such as from Rotax, Continental
and Lycoming.
Most automotive engine conversions can benefit from the use of the E3 engine monitor.
The E1 can measure up to 4 total EGT/CHT channels, a universal RPM input, a universal
temperature sender input, a universal pressure sender input, and the a
ircraft's supply
voltage.
66 different engine setup configurations possible
Universal, programmable rev counter (engine RPM) with digital and analog readout,
with a programmable high alarm limit
Programmable engine Hobbs meter (password protected) and runn
ing timer (flight
timer) with automatic flight log
Can monitor up to four total programmable thermocouple channels for EGT and CHT
probes with a user programmable high alarm limit
A universal temperature sender input with a user programmable low and high a
larm
limits
A universal pressure sender input with a user programmable low and high alarm
limits
Supply voltage measurement up to 30V with a user programmable low and high
alarm limits
Maximum recorded values for all measured values are stored in non
-
volat
ile memory
High accuracy: Built in thermocouple linearization curves and cold junction
compensation
Thermocouple temperature probes can be common K, J or E
-
type thermocouple
probes
Uses standard automotive temperature and pressure senders
Special Rotax 912
/914 engine monitor mode utilizing the standard built in Rotax NTC
CHT probes
Supports the new Rotax 912/914 4
-
20mA oil pressure sender
Download E1 Manual (PDF)
Price: $345 + shipping from CA
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