Engine Bay Sheetmetal Repairs

This morning I continued with welding sheetmetal repairs in the engine bay.

Before I did that I actually noticed a very small second hole in the driver’s side floorboard. Yesterday I welded shut one hole that measured maybe 1/4″ in diameter. This second hole was about half as large and located over by the door sill. I welded it shut with just a few short bursts from the MIG.

Then I used the Dremmel with the small cutoff wheels to grind off each weld flush to the floorboard.

In the engine bay, on the passenger’s side of the car, there were several holes where non-original accessories, for example the electrical fuel pump, had been mounted. Since I’m taking the engine bay back to stock configuration, I needed to repair any of these holes. Here are a couple of pictures of the holes toward the front and also two up higher in the engine bay.

Prior to any welding I removed any surface dirt and/or rust by cleaning around each hole using a 3M Clean & Strip Disk.

Then I welded up the holes using .023″ welding wire and Argon/CO2 gas. The lower rails of the engine bay were made of thicker sheetmetal, but on the sides I tried to back up the metal with some solid steel plate in order to diffuse the heat and prevent melting through.

Here is the finished result before I started grinding the welds.

First I began grinding off the proud welding metal using two cutoff disks mounted into my Dremmel.

Then I decided to mount three cutoff wheels in my 4 1/2″ angle grinder and use the edge of it to try to further smooth out the welds. This worked very well and provided a much broader footprint for flattening the welded areas to the surrounding sheetmetal.

On the firewall, in the niche where the brake master cylinder resides, there was a crack in the firewall. From what I’ve heard this is fairly typical and caused by the force of stepping on the brakes; the sheetmetal on the firewall eventually fatigues and can crack. In addition to repairing this I plan to install a firewall brace that has been invented to shore up this mounting point and therefore remove any slop in the brake pedal motion. Before beginning the repair I cleaned the area with a wire brush, on both sides of the firewall.

Then I re-aligned the sides of the metal where it had split by tapping on it with a body hammer.

Then I welded the two cracked sections back together.

And then I ground down the weld flush with the sheetmetal.

When I bought the car it had hoodpins, which are not original to the roadster. My intention has been to remove them. I removed the pins themselves and then I wanted to seal the holes they had been mounted to. I began by trying to raise the metal around the holes, which had been bent downwards to install the pins. I just used a heavy hammer to pound upwards from inside the cabin; no need to be delicate as I plan to fill the dents later. The main reason to try to roughly straighten the metal was to minimize the amount of filler required later. Here are the holes where the hoodpins had been.

So I just welded over the holes. Later I plan to fill the indentations so eventually there will be no evidence that the hoodpins had ever been installed.

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