Richard, yes they are addictive but with good reason, Just going out to the field with just your plane, radio, and a small amount of fuel, flip and go with that little PAW is worth it no glow plug or battery hassles. If you notice the posts, the Irvine 40 diesel seems to be the " cult" engine in the 40 class ,many of us have them, but sadly out of production. However they can be found, The issue with the engine was that big brass contra piston dropping, Mr Davis comes to the rescue and makes a head for it yup, a replacement head for an engine already a diesel, end of problem. Then its goes out of production, after a bunch of us pleaded our case Davis sets up a CNC program and back in production, The Q40 irvine glow is the same engine and just needs the diesel head. The OS 2 strks make great diesels also and the Kand Bs , Foxes, made here in the USA same , Super tigres too but enough for now , just go enjoy martin

One more thing since back pressure not a issue with diesels many of us pipe the exhaust to the rear of the plane with thinwall aluminum tubing, plane stays nice and clean

If you check the Davis Diesel site there is also a good concise narative on conversions