Saturday I did prep work for welding. Drilled out the 1/8" holes to the correct 1/4". Took the grinder and wire brush to all the seams of the weld. Once the angle grinder was out, I went to town on the underside of the car with the twist knot brush. It's amazing how resilient 37 years of gunk can be, getting flung at my face by a brush spinning at 11,000 rpm; I was just a wee bit dirty [a lot of what was getting flung at my face was the undercoating, not gunk - ed. 9/1/2008]. I went at that until my arm was just too tired. The prognosis is great: zero rust on the center channel and only very minor touches of rust on the part of the floor pan I've uncovered.
After my arm got tired, I went over to the engine to finish removing the last few cover plates. The air deflector plates and cylinder covers were easy, but then I got to removing the crankshaft pulley to get to the last piece of shroud, and that bolt is stuck on there like you wouldn't believe. I tried some tapping and liquid wrench. No go. It was getting late and I was getting frustrated, so I decided that before I broke something, I should go home... had a pub crawl to make.
... a pub crawl that left me less than 100% wanting to work on Sunday. Still, I had enlisted the help of my friends, so I wasn't about to flake. Here it is in the middle of the process. Chris and Matt are at Home Despot buying more MIG wire. Even though we have the car on jacks, you can see there ain't too much room to work underneath.
Here's the basic strategy. While I press down on the pan from above, Matt welds the seam at about 2" intervals. Once it's held in place like that, we pound the seam down well with hammers and chisel, and he goes back and fills in all the previously drilled holes. This photo shows it pretty well. We pretty much have a weld every place there was a factory spot weld. That floor pan ain't going anywhere.
The trickiest part was the jack bracket because the one that came attached to the new floor pan had a few extra parts as compared to the factory bracket. We decided to keep the new setup since it seemed to make the whole assembly stronger... which it needs since, disappointingly, the new pan is thinner than the existing pan. They don't make 'em like they used to I guess.
Back when we prepped the new floor pan, we cut away the vertical part (the one that isn't really part of the floor pan, but that attaches to the back of the floor pan). The existing piece seemed of better quality, and it made no sense removing it. But what this meant is that now we left ourselves a tricky job because, well, look at the picture and you may see why. With the jack bracket wrapping around below the floor pan, the geometry, bending things out of the way, and the order of welding all require some planning ahead.
Not that big of a deal. Next we welded in the heater cable tube (I made it out of a piece of ordinary brake line and bent it around the tire), welded in the bolt for the battery bracket (it's connected to a bracket that spot welds underneath), and that was that, about 3 hours later or so. We sprayed the whole seam with a cold galvanizer; capillary action should suck it in between the pieces of metal.
Here's the finished job. Perhaps the oddest thing is that the solvents in the cold galvanizer dissolved whatever super duper wimpy coating they put on the floor pan to ship. You may be able to see little puddles of black along the floor pan. Yeah, that's dissolved black paint... or wax... or whatever it is. Not terrible, except if it's such a bad coating, I don't want to paint on top of it. I'll have to go down to bare metal before I paint. And I'm lazy to do that.
Next week: tackle that crankshaft pulley, get the engine parts ready for sand or bead blasting, finish cleaning that darn underside, and start painting this thing.
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