I'm pretty hard on them all But a lot are compromised by Poor management Particularly starting techniques and Avoiding Prohibited rpms, MP/ Rpm combinations over propping and using motor for short periods where they never get Properly warmed up. Motor cowled with adjustable Cowl flaps and properly Baffled with Air blast tubes on the parts that need them to be specially cooled and Lagged fuel Lines etc. ie Properly Installed . Nev