ALL Big Bore Continentals are susceptible to shock cooling especially during descents, unlike Lycomings, that is just the way it is. I have replaced numerous cylinders due to cracking caused by rapid decents and improperly set up fuel systems. The operational procedures, as you are aware of, are somewhat strict and must be adhered to or it will cost big bucks. I would recommend that the fuel system be set up and checked annually by someone VERY familiar with setting up the fuel system. An improperly set up fuel system will result in lots of problems to include cracked cylinders, even though the published procedures are adhered to. To properly set up the fuel system, some special tools are required along with TCM SIB 97-3 and not to be attemped by a novice A&P.

The typical ccylinder will cost anywhere from $500 to $800, depending on what needs to be done to fix it. Replacing the cylinder is about a six to eight hour job depending which position the cylinder. Being a 206, the job is a little more difficult and more time consuming as the bottom cowl is fixed. Setting up the fuel system requires a set of gages plumbed in to the injector (reading unmetered fuel pressure), using the instrument panel gage to set the fuel system is a no-no as the panel gage is reading metered fuel pressure and the fuel system will end up all fouled up. Continental provides a Service Instruction 97-3 that has a wealth of info to set up any TCM fuel system.