Problem isn't the cooler or the vernatherm, its the lack of airflow through the cooler. I have a 13 row cooler mounted on the firewall with a 4" duct feeding it off the back of the #4 cylinder. I am running a sam James cowl with a plenum, there just isn't enough air available in high alpha climbs to run it. I have measured it extensively with a digital manometer. There is only a 1.8 in/h20 drop across the cooler in climb. In cruise I get a 3.2 in/h20 drop with my cowl flap open, oil temp drops into an acceptable range for me (205-210), but a little warm for some of my less risk tolerant friends. It has a little over 100 hours on it and it hasn't come apart yet
CHT's in climb are great, I can hold Vy to whatever altitude I want and the hottest cylinder is right around 400. I could divert air from the cylinders to feed the cooler, but I don't want too....I am running SDS EFI, I think I can control a fan based on oil temp with it, so I thought about a cooler with a fan on it. This isn't exactly a stock 360 either, everything is against it as far as oil temps go. Cold air intake, 10:1 compression, piston squirters, custom Cam, etc. For what it is it actually cools pretty well, but it could be better.