The crack was right here where #4's tube comes into one with #3.
The crack occurred right along the weld. I got on the phone with Larry Vetterman, who said that he barely fields a dozen complaints per year. But he also mentioned that there aren't too many RV-7 200hp angle valve IO-360 exhaust kits out there, so this is all new stuff. When I emailed him the photo above he said it would be a quick and easy fix, just send the exhaust to him and he'd weld it up. Ironically, he's located in South Dakota, and I had just basically overflown where he's at two or three days ago. Oh, well. Box it up, send it up there for repair. I'll be down for about two weeks.
I took a couple of photos of where my EGT probes were drilled into the exhaust, just in case I had to replace those tubes. Here's #3.
Here's #4.
Still working on the baffles. Basically, on the trip to the east, my oil cooler brace (crimped end stainless steel tubing) broke at some point between Chicago and Boston. That allowed the oil cooler to flex, wreaking havoc on the baffles in the back left corner. I'm replacing the brace with a more robust setup, and in the process I'm totally rebuilding these baffles with major-league beefed up components.
First of all, the back left corner is getting an 1/8" angle instead of 1/16".
Also, the inner/outer joint on the back left baffle wall is getting replaced. There used to be just bent flanges here, .032" on the inner, and .040" on the outer. Screw that. It cracked right up the rivet line. I'm going with .063" on the inner and .125" on the outer. No question this will be infinitely stronger than the thin stuff that used to be here. Even though I'm going to prevent all flex in this area I still want it as robust as possible. Those black marks that don't align -- those were edge distance tolerance marks...if they met I'd be right at the limit. As you can see I had a little room to spare.
Here's another weak point that I plan on enhancing. This is the lone bolt that attaches to the cylindrical nut inside the boss on the back of the cylinder. Prior to now, my oil cooler was set up kind of raised up and tilted inboard to maximize the exposure of the oil cooler to the incoming air. It worked great, apparently, but it left this area on the back wall with just the one bolt going through the baffle wall...it didn't tie into the oil cooler or the duct framework. When the oil cooler flexed, it cracked this area as well. In the new setup I'm just going to install the oil cooler and duct framework aligned with the left edge, and this bolt will integrate through an angle on the bottom of the framework.
