Cylinder Head Temperature Gauge

A very valuable gadget to have is a CHT gauge. This will give you a relative reading of how well your engine is cooling. There seems to be no hard and fast rule of what is a good temperature, however it is obvious that hotter engines can lead to heat seizures. A CHT will quickly tell you if a new fuel is bad or if some modification you have done is causing your engine to run hotter.

Roughly a Vespa engine will run at between 320F and 380F, different engine set-ups will run different temperatures. The CHT is not a replacement for listening for engine problems (you are unlikely to be staring at it constantly), however it will tell you when to listen more carefully or not.

Pictured above Exhaust Gas and Cyclinder Head Temp Gauges. The hardest part was making the hole in the glovebox, I made a bit of a mess but most of what you see in the pic is due to dodgey touchup paint. Cyclinder Head Temp Gauges supplied to me by http://www.wadeair.com.au/

Tips:

• • straighten out a coat hanger and push that through the frame, through the clutch cable hole.

  • label the wires from each sender (because they are both the same colour

  • when drilling the hole in the glovebox, I found taking short jabs, made it easy to get the teeth cutting in the same spot

Notes:

• • EGT changes quickly with engine speed

  • CHT change slowly

Although the above is not detailed, the following links will show you all you need to know about fitting a CHT

Cylinder head temperature gauge installation

Installing a Cylinder Head Temperature Gauge

Alternative CHT

One experience with the Westach gauge was that it lost accuracy after a while and started reading high. The gauge was replaced with the following more accurate guage

MICRO 1000 CHT

http://www.aircraftspruce.com/catalo...HT_gauges2.php

http://www.aircraftspruce.com/catalo...1chtPROBES.php

http://www.aircraftspruce.com/catalo...o1chtLEADS.php

Exhaust Gas Temperature Gauges

The gauge above has a EGT (Exhaust Gas Temp), this may be very valuable for a mircolight aircraft where the engine runs at a constant RPM. In that case the EGT will quickly tell you if the engine is in trouble. However, the EGT reading changes quickly with RPM, so for a scooter it's use is limited. It "might" prove a useful tuning tool in conjunction with a rev counter.

More Information?

It would be nice to find the following information:

• • Is there a digital CHT with programmable warning light or beeper?

  • Is there a cheap digital CHT with backlight?

  • Is there a EGT/RPM gauge?

  • Is there a cheap CHT temperature switch? It would be nice to switch something off/on to save the engine