Oil cooler
I did something a bit different with the oil cooler. Since we typically take the oil cooler air from behind cylinder #3 and it always runs the warmest CHT, I am pulling the air from the front baffle plenum chamber. The oil cooler is located a few inches above the lower cowl and I’ve located some louvers beneath the cooler on the cowl.
A benefit of this modification is that my cylinder temperatures are within 25°F of each other. My average oil temperature is 190°F. I plan to fabricate a skirt out of rubber baffling material to seal the gap between the oil cooler and the cowling louvers this summer and see if this lowers the temperature a bit more.
![Oil Cooler N11YM](https://glasair-owners.com/wp-content/uploads/2018/11/Oil-CoolerN11YM-054.jpg)
The thing I would have done differently would have been to make the inlet at the baffle face more trumpet shaped.
I custom made a 4:1 straight exhaust since I don’t have a nose gear and to save weight, eliminated the nose gear mounting brackets from the front of the cage.
![4 into 1 straight exhaust](https://glasair-owners.com/wp-content/uploads/2018/11/Oil-Cooler-N11YM-056.jpg)
Cylinder cooling
There isn’t much cooling air that gets to the lower fins on the cylinders. Cut 7/8” tall x 1.75” cooling slots in the forward engine baffles to realize a 25-30° reduction in CHT. This isn’t necessary on the IO-390 engines, but very beneficial on the 180 hp parallel-valve IO-360 models.
Any GlaStar or Sportsman with a parallel-valve 180 hp Lycoming can benefit from these. They aren’t incorporated into Glasair’s baffle kits, so they aren’t installed on TWTT Sportsman, but I generally tell customers so they can modify their baffles later on.
![Locate the slot just below the cylinder midline as shown where the fins are the deepest at the base of the head.](https://glasair-owners.com/wp-content/uploads/2018/11/Cylinder-cooling-sportsman-N11YM_02.jpg)
![Locate the slot just below the mid-line of cylinder 2. Sandwich foam between the aluminum baffles and seal in place with hi-temp silicone.](https://glasair-owners.com/wp-content/uploads/2018/11/Cylinder-cooling-sportsman-N11YM_01.jpg)