I can state with certainty that the number of Magnum 46's returned for repairs is very low. This suggests a very reliable engine. The only problem I have is that the owners manual says to break in the engine very rich. It is common knowledge that an ABC engine should be broken in only slightly rich in order to get the sleeve hot enough to expand and relieve the tight fit at the top. Most of the early failures with the Magnum 46 involve that problem. There are, of course the worn out engines, and the occasional bearing failure, the rusted engines (no after run oil) and the dusted engines from running on a dirt field. By the way, I know the guys who do the repairs for Global Hobbies.
JJ