1973 C-172M Install Engine Temps

1973 C-172M Install Engine Temps

Later this month during my annual, I will be installing EGTs and CHTs (bayonet style) on my Lycoming O-320-E (150 Hp) engine.  I will add two multi-switch indicators so I can read one at a time, all EGTs and CHTs.  (No money for an Engine analyzer)  I humbly request suggestions and cautions on the project, and in particular, where to locate the displays my instrument panel.  How do you mount these gages that don’t have a standard place for an instrument?

All this work will be done under the direct supervision and help of my A&P and AI.  I'm sure they know how to do it, but more heads are usually better than 1 or 2.

Options (first thoughts considering how to get the most out of them):
1) I have one spare small, instrument circle (pattern) on my standard instrument panel lower left of my Yoke adjacent.  I am thinking of putting the CHTs there and my EGTs nearer to my mixture control facilitate leaning. 

2) Put the two gages together so I can easily compare the CHT to the EGT for each cylinder as I step through them.  For those who have experience with this, I would appreciate some advice.  (This has the advantage that if I do get the money for an engine analyzer, the wires will already be located in the right place.  (This assumes the potential analyzer I purchase can be used with the type of thermocouple in the CHTs and EGTs)

Other considerations will be replacement of elements and best ways to run wires.

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Re: 1973 C-172M Install Engine Temps

I would recommend that you put both gages together for ease of comparison and ease of view.  My analyzer is right over my left knee probably in the same location that you are speaking of.  I am the only one that can see it there, and it is somewhat ackward for me.

I think you would get more value in having the information together in one location and where at least another pilot could see.  Near the mixture control would be a fine place for viewing and tweaking the mixture.

One of the features of the analyzer that you will be missing is a red light to indicate high readings.  I have a light that is set to come on if any cylinder reaches 390 degrees.  I start to do something about it and have things under control before anything ever reaches 400.  That may be a somewhat low setting for some people, but it keeps me in my comfort zone.  For my plane, that high CHT is always (usually always) my number 3 cylinder.  You will find that one of yours is usually out in front of the others, and you can leave it switched at that one unless you are switching through them.

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