Does anyone know of detector available for small aircraft (not transport
aircraft / Part 135, 121) that can be installed in the cowling(s) to detect
the presence of some condition (excessive heat, IR, etc.) that would lead to
an in-flight fire? Examples of those conditions might include a failed
exhaust header gasket, loose exhaust component / fastener, growing hole in
the muffler or an exhaust pipe, or even a cracked cylinder.

A lot of real dangerous things can happen BETWEEN oil changes where they
could be easily spotted and it seems that such a detector could give a pilot
a much better chance of getting an airplane on the ground before a fire got
started by giving them some time to reduce power (which might prevent a fire
altogether) and head for the nearest airport to check things out. It sure
seems it might be several minutes that failures like those above could be
detected, and detected before they begin to catch things in the cowling on
fire around them.

I have done some checking and transport aircraft, some helicopters, and even
larger power boats have systems that detect excessive heat in their engine
compartments. Some discharge halon bottles, and some of those in boats even
shutdown engines (clearly not advisable on single engine aircraft).

Anyone know of an "affordable" and light weight detector for small aircraft
that might monitor the airflow near the bottom of the engine before it exits
the cowling or perform some other monitoring function to detect a condition
that could lead to an in-flight fire?

George