I got my exhaust from Larry Vetterman today. On Larry’s recommendation based on my engine and sump, I went with the four pipe system. This is a little unusual for RV’s as it seems that most people go with the crossover exhaust which ties cylinders 1 and 2 together as well as cylinders 3 and 4 together resulting in two pipes exiting the cowl. I’m glad I went with this system for a couple of reasons. First, I just think it looks better with four pipes exiting the cowl. Second, the cabin heat muff for the four pipe system passes the air over two pipes instead of one, so Larry claims that you get much more heat out of this system. Here are the pipes as received from Larry. The upper four pipes have the flanges on them which mount to the cylinders. The lower four pipes have ball joints which gives the exhaust system some flexibility to prevent cracking.
Here is the cabin heat muff.
I loosely assembled the upper and lower sections for each cylinder.
The instructions call for using sheet metal screws to hole some of the parts together in the cabin heat muff. The heat muff in our Cardinal is assembled this way and every time we open the cowl, there are a couple of screws missing. The plans specify that you can optionally install nutplates, so I installed some K1000-06 nutplates and ordered some extra AN526C632-6 screws.
Here is the temporarily assembled heat muff. The muff will surround the exhaust pipes from cylinders 1 and 3, and the air inlet and outlet are on the top.
Here’s the inside of the muff showing the nutplates on the top and bottom of the end caps and showing the rods that connect the two ends of the muff. I’ll assemble this permanently once the exhaust is installed on the engine.
