Orma,
The 0-200 has "air blocker" plates between and on the bottom side of the cylinders to force all cooling air to move through the cooling fins only. Same for front and rear baffles. If your baffles allow any air to move from the top to the bottom inside the cowl anywhere but through the cylinder fins you need to close the area down. It doesn't take LARGE inlets to cool. I actually made mine smaller than what the cowl started out and my 0-200 runs at 300 to 325 CHT and 180 to 210 on the oil temp and I don't have an oil cooler. You need good tight seals, a lower pressure on the bottom side, and don't let any air through without touching the cooling fins. To get better outflow on the bottom a small down-turned lip can be added to the exit hole. You will see that lip on some "certified" spam cans on the ramp. That's what it's for. It is a small increase in drag but creates a low pressure area at the exit to help "suck" the cooling air down and out. Larry Flesner
