I've continued to chip away at the baffles this week. I didn't get any pictures, mostly because the work involves hours of fiddling just to get something trimmed 1/8". Not much to show with that kind of progress. I got the front center baffles riveted to the intake ramps and the conical gussets for the corners finished and match drilled to the ramps and side baffles. I couldn't get the gussets riveted in place yet though - I have to wait for Rose to get back home so she can help me dimple a few of the holes that my squeezer won't reach (they're 1/8" rivets, so my pop rivet dimpler won't work either). I need her to hold a block with one of the dimple dies in it so I can hold the other one and hit it with a hammer to set the dimple.
In the meantime, the next task is to trim down the baffles so they fit underneath the cowl. The plans say the top of the baffles should be between 3/8-1/2" from the cowl.
You have to put the top cowl in place to scribe the contours, but just setting it in place doesn't do any good since then it's propped up by the baffles and not setting on the bottom cowl. So the top cowl has to be held in place but higher up. I made some blocks to hold the top cowl 4" up from the bottom, then used a block of wood and sharpie to scribe. The first cut line just needed to be enough to let the cowl set down all of the way without surpassing the 1/2" gap allowance. It took me a couple of rounds of trimming to finally get it.
Once the initial trimming was done, then the stressful part began - slowly cutting away at the baffles to get the right gap. One of the tricks I saw online was to use paper clips to help find the cowl contour. I put paper clips all around the baffles then set the cowl in place, pulled it off, then measured 1/2" down from the top of the paper clips. It didn't work perfectly, but it was good enough to get me 90% there. Then it was just a lot of back and forth to creep up on the right gap. Time will tell if I got it good enough. I realized after the fact that I had neglected to screw down the cylinder 3 and 4 baffles again before I did the trimming. Doing that ended up pulling the baffles down a bit, so the gaps for those might be a little bigger than ideal, but I had tried to get about 7/16" for most areas, so I have a little wiggle room.
With the baffle height done, I can finally start working on the oil cooler. The plans say to set it as high as possible for the best cooling, but you can't do that until you know where the top of the baffles are. There are a number of pieces to the oil cooler mount. There's sort of a shelf that goes in front of the rear baffle to act as a stiffener for hanging the cooler. It's super hard to see in the picture - it's the mirror looking piece. In order to get this put in place, first I have to figure out where the cooler is going to fit.
I spent way too much time going back and forth trying to figure out where the cooler should be. I finally landed on a spot, but unfortunately it means I'll have to make a few changes to the normal setup. The reason it's going to be slightly different than the plans is because I changed the corner of the baffle design a long time ago. The stock setup is well known for causing cracks in the baffles over time. The weight of the cooler shaking on the engine is just too much for the baffles, usually causing cracks on the corner flanges. One fix for this is to beef up the corner with some 1/8" aluminum angle, which is what I did. The problem is that the stock rivet and bolt locations for the cooler bracket just won't quite work with the angle there. Most people just slide the cooler over just enough to barely let the rivets clear the inside corner of the angle, but in doing so you end up blocking almost a full row of the cooler. I don't love that, hence my decision to tweak a few things by making my own parts.
I ground down a portion of the inside cooler flange to fit around the engine mount. Van's shows a number of different options for how to orient the cooler, but all of them require grinding away the flange somewhere.
The stock method for mounting the cooler is to first rivet a bracket onto the baffle, then bolt the cooler on top of it. I'm also adding in an oil cooler shutter, which will have to be sandwhiched in between the bracket and the cooler.
Here you can see the baffle stiffener a little better. This is going to take some thought to make it work. I will definitely have to cut off the flange on the lower portion because it won't line up well with the cooler bracket. I'll probably just rivet a new piece of angle to the top side of the shelf and use that to rivet it through the baffle to the bracket (the standard flange drops below the shelf).
I tried and tried, but nothing I did allowed the stock bracket to be in a position where the cooler would bolt through the outside baffle corner in the right places. So I just decided to make a new bracket instead. It's essentially the same as the stock one, but with a wider outside portion. That gives me a lot more room to slide the rivets further to the outside so they are in the right place on the corner, but still allowing the cooler to be further inboard where it can catch the most air.
That's where I ended the day. Tomorrow I'm going to do my best to get the cooler and shutter mounted before I have to leave for the week for work.
