SJ, I was just giving you a rash, because I know I read somewhere that Tinnerman nuts require type B screws, due to difference in thread pitch and very slight difference in root diameter between type A and type B. In my experience the type B screws seem to hold better.
I had an O-520 in an L-19 Bird Dog and could never figure out why???? they put the oil cooler in front of the cylinders, blocking the cooling air, and perhaps pre-heating the air going over the cylinders? Am I just being stupid, or was this a bad idea?
The cooler doesn't block any air. There's a baffle behind the cooler to prevent air from going down in front of #5. The cooling of #5 comes from the pressure cowl doing it's job. Ram air to an exposed head isn't very important judging by how both my front cylinders are blocked and I have really even temps as a result. The dam in front of #6 improves the cooling of #4 in my engine. Maybe I'll pull the shroud on #5 and see if the temp distribution changes. Naw, too much work. It's been a journey to get my temps where they are. I'm not messing with it.
The question remains, does the #5 shroud increase or decrease the CHT at #5?