Wednesday, October 5, 2011

Planning for my cowl repair

The reason for my cowl repair is best explained by photos.

First, here's a shot that includes a clear look at the cowl on my car. Notice how nice and flat it is?

And here's what it should look like. (h/t to amd for the photo)

So I'm missing a group of louvers, and two holes that the wiper pivots come through. There is actually a reason that was modified. When the car was race prepped, they cut out the underside of the cowl to save weight. The metal they cut out is necessary to support the wiper pivots, and to keep water off the floor. Once that was gone, the louvers had to be smoothed so water wouldn't run straight onto the floor. Since wipers aren't needed on a race car, they also smoothed the wiper holes on the outside. One wiper pivot mount was lost with the metal that was cut out, and a stud for the remaining mount was damaged in the process.

This photo clearly shows where the lower cowl pan has been cut out while also showing what a mess the wiring is right now. The goofy switch and gauge mounting are there so I can start the car without the dash in it.

My current thoughts are to go custom with the repair, and leave the smoothed cowl and as much of the weight loss as possible. Since the car has mini tubs and other race mods, that wouldn't be out of place. Plus, it's been on the car so long I almost feel it'd be a shame to undo that part of it.

So what follows shows how I could repair just the bare minimum, adding wipers but leaving the factory louvers smoothed. The plan certainly has flaws - for example, the washer squirts through the louvers, so that is yet to be accounted for.

Now, more pretty photos ...

Here you see the draft cut lines on the donor part. Ignore the obvious mismarking there at the bottom. That was caused by it being in the rafters, and me being on a ladder, when it was marked. Not the easiest way to do it, but definitely easier than taking it down from there and then having to put it back (or have it in the way).

One thing to note there is the feature just to the right of the leftmost cut line, at top. That indentation will ensure that I get the part back in the right position at the windshield pinch because it has to match up with the same feature stamped into the metal I will be welding it to.

This shows the cowl marked with the basic cut line to just spot the wiper holes back in. It's about 1-3/4" square. The welding here is the only part I don't plan to do because it'd be easy to warp and it shows A LOT. So I think I'll hire it out to the best TIG welder I can find around here. All the rest of the welding will be MIG done by me.

Here, the blue tape represents the area covered by the replacement patch. The contours of the pan are not per the tape. The pan is deeper than that, which will give me room to reach inside it to weld it up at the firewall.

The patch panel will be cut from the donor part as was shown above and includes the missing pivot mount. Again, just to the right of the leftmost tape line, at top, you see the alignment feature I mentioned. The panel will be welded in at the windshield pinch and then to the lip which was left at the firewall. I'm unsure right now if the firewall side will be lapped and plug welded, or butted and stitch welded. Probably best to butt it, but OTOH, it should never get wet so there's no worry of having a place for it to rust. Also, since it's steel to steel contact, no corrosive reaction is expected from having the two overlapped pieces.

So ... am I crazy for taking this approach to "restoring" a real A12, or not? Remember, putting the louvers back on the cowl has an impact on what I have to do on the inside, to catch and direct any water that comes through them. Would there really be that much more value in going with the louvers, given the other race mods on the car?

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