I had never heard of ColorTune until Bill Tucker mentioned it at a Tech Session. Well a couple weeks ago Gary Brown's MGA was running really rough so he brought it over. The first thing we did fixed the problem. The timing was way off. It had recently been serviced at a local shop. In appreciation, Gary bought a ColorTune for the club.
ColorTune is a device that allows you to actually see the combustion inside the cylinder while the car is running. The part below that looks similar to a spark plug actually replaces the spark plug. The long thin piece screws into the top of it and the spark plug wire plugs into the top of it.