Welding the body to the chassis - Project Frankenwagon, part 6

Submitted by dannix on Thu, 04/11/2019 - 11:33

It's been a few months since my last post on this project and a lot has happened since then!

We left off with the '67 VW Type3 body dropped onto the '90 Mazda MX-5 Miata chassis:

I brought it inside the garage and began working on getting the body into the correct position on the chassis. 

I knew that if the body could be too low on the chassis such that the tires would hit the fenders. But when I put the car seat in there and sat down, I knew that I had to put the body as low as possible to have the best/safest view out of the windshield. Issues with tire and fender clearance would have to be sorted out with adjustments to the suspension, body work, smaller wheels, or some combination of the above.

With the location figured out and hammered down, literally, I needed to lift it back up so I can clean up all the edges, repair some rust, cut some more things out, etc. 

After staring at it for quite a while, I MacGyver'ed up this marvel of engineering with things found around the garage. Two saw horses, an off-road jack, some ratchet straps, and the engine hoist. 

Here's the YouTube episode, explaining things in more detail and showing how it all works:

Now I could begin repair all the rust to VW body. Anything rotten had to be cut off and replaced with fresh metal, like this passanger-side door hinge bracket:

It was completely rusted and broken, it actually wasn't supporting the passenger side door at all. I cut it out, welded in some 16-gauge steel with lazy lap welds, then made a new door hinge mounting plate out of ~12 gauge steel that was cut off of an old bed frame (I've heard that bed frames are made out of the worst steel, but I had no problem welding it). There's no caged nut-strip like what the other three have, so the door will have to be put on before the passenger side fender. I don't think that should be a problem. 

Yeah I know the welds aren't pretty but this is a git-er-done type of affair. 

I also welded on a strip of 22-gauge below the windshield to have something to bolt/weld/fasten to. What that will be I'm not sure yet, I'll cross that bridge when I get there, but this was 1000x easier to weld in place now because I was able to access it from below. And it will leave me with enough room to install some wiper linkage.

I'm almost out of sheet metal, but I still have enough to do the rockers in 18 gauge. Several months ago I bought one 3'x6' sheet of 18 gauge and one 3'x6' sheet of 22 gauge. Maybe next time I should get all 19 or 20 gauge.

I finished cleaning up all the rough edges on the VW body and the Miata chassis and prepped them to get welded together by removing all the paint and spraying the bare metal with weld-through primer.

Then I welded the two chunks of metal together:

I want to share this one first, but note that this is not be the actual ride height because the body was still sitting on jacks when the pic was snapped, and therefore the weight of it wasn't sitting on the suspension. I wanted to hang the fender to make sure the wheel was in the center of the wheel well before welding the body to the chassis.

I should have took a pic of how far the tire was sticking out but I was in too much of a hurry I guess. But I measured how far the tires stuck out past the fenders and it was bout 3/4". 

Notice anything different? No more braces and no more hoist holding it up.

This is a screenshot from the video:

Umm, do you guys think the front wheel looks a little forward? Maybe it is but it doesn't look too bad. I'd rather it be too far forward than too far back! I knew that the wheelbase would be 3/4" too long, I guess this is the result of that. But I can definitely live with it.

And this is with the body on the weight of the suspension, so that's the actual ride height. I didn't have enough hands to measure it and hold the fender at the same time, but it looked like the tire was sticking out past the fender only about 1/4".

Then I put it up on jack stands:

When welding the VW to the Miata under the cowl, I accidently caused a bit of rubber to catch on fire. Here's the fire damage. Very tricky to get some pics of it, had to use a little mirror. 

Here it is before. Maybe I should have wrapped some foil tape around it or something.

All I can see is that the rubber surrounding the wires is extremely charred. I was worried that the insulation around the wires melted, the wires shifted around, and now several of them are shorted. To find out, reconnected the battery, ECU, ignition module on the steering column, and the fuel pump, and I fired up the engine. It ran great! 

I also made some rocker panels, as shown in the youtube episode embeded above. Here's the driver side rocker panel:

And here's a little patch on the passenger's side under the B column:

Will for sure need some fiberglass body filler, but that's ok with me. 

Here's one of the more complex pieces, it's the part of the rocker panel that is hidden behind the fender. 

Oh, and the inside of all the patch panels get sprayed in weld through primer before they get tacked in. Then afterwords, if there's access, I hose them down with more paint. 

Then I started working on the area below the B column. 

It's not pretty, but I plan on smothering it in seam sealer, followed by some sort of paint with a textured build, like truck bed paint or rubberized undercoating or something. I'm not trying to win any car shows here. 

And I fabricated some door sill plates. I actually managed to make something pretty!

(don't look at the welds on the left, I was having problems with rust or paint or something junking up the welds).

They're strong enough to stand on, probably (I'm not going to find out). Should help keep the car from flexing, too.

This video shows me making them:

Next: Putting the "car" back together - Project Frankenwagon part 7