Jackpoints welded, horn pockets in, and some aluminum stuff riveted

I returned to the front of the car after Thanksgiving to make the inner lip for the grill to bolt to, make and install the horn pockets, make the horn mounting tabs, weld the frame extensions and jack points and build the airbox for the oil cooler. All done.

When we last left the front of the car, we had cut out the grill and rough-cut the grill slats. These are all fiberglass; Sierra Madre, Fibersteel, Rusty Tubs and others offer aluminum aftermarket grills (and aftermarket fiberglass), but they’re all money and I don’t see how they improve the look or functioning of the car.

I got into the horn pockets first by drawing circles on the bottom of the front of the car. There are no measurements for where these are supposed to go, so I looked at as may pictures of real 550s I could find, and guestimated the location by proximity to the grill, the jack points, the fender wells and the brake cooler intakes.

Here’s the best shot I could find—a Spyder Factory replica of 550-0090:

Here’s my mark:

I drilled a hole near the center to see where I was coming through inside. Note how far off the circles I drew inside the “frunk” were:Made me really glad I decided to measure and draw it from the outside before cutting.

Fibersteel makes a horn-and-fiberglass-pocket kit that looks pretty nice. It costs more than $350. I did not buy it, preferring to make my pockets out of aluminum for, well, significantly less. Here’s one press-fit into the hole I cut.

And from the top:

I flanged over the sharp edges. . . .

Then glassed them in with kitty-hair:

From the bottom they already look about as finished as the FiberSteel units, but I’ll clean them up underneath later with more kitty hair and some filler.

Next it was on to the rear jack points. They are longer than the fronts, and require welding to the rear frame rail.

Instead of clamping them on and tack-welding, I decided to drill, tap, and bolt them on first, since I liked that the front ones went on that way.

I welded the bolt head in. Then put a bead on the jackpoint from underneath.

After that I went back to the front of the car. I cleaned up the inside of the frame tubes and the outsides of my extensions, sanded the paint off the spots where the jackpoints meet them, bolted the jackpoints on and the extensions in the frame tubes, shimmed-up the extensions as high as they would go, put some wet rags around them to protect the fiberglass,

and then burned wire.

I installed the jackpoint cups next, widening the holes they were in just a little to get them to sit flush against the bottom of the car.

Then took them off again and got after the horn brackets.

With the horns so close to the front bulkhead it was just a matter of bending one of the three little bits of metal that came with the horns.I welded a couple bolts to the bottoms of each one to make studs…Then popped a rivet in them, then glassed them in later when I was doing the lip for the grill.

The grill lip is just four strips of 22-gauge aluminum, folded over and riveted together. I bent it into shape then “glued” it in with kitty hair.

Which would’ve probably held if I’d remembered to drill a bunch of holes in the aluminum so the ‘glass could bleed through.

As it was, it wan’t strong enough, so I hit it with a couple layers of weave the next day, and more kitty hair.

Test-fit the grill with some #8 self-tapping sheet metal screws. . . .

Then on to some CAD for the airbox . . .

I shaped this piece of thin angle to the grill by slotting it. . .

…Then brazing the slots closed after I got the shape:

Then I screwed that through with the grill screws, more CAD, and finally some 18-gauge aluminum action!

With no brake bender, I improvised.

Et voila!Things went this way for several days. The intake is four pieces: the one you see above, a bottom tunnel piece, a short extension from the top right, and a cover piece that fits over that and goes to the back. I’m certain that a good duct maker could have done this in two steps, but what I did is strong.

I did make a shutter to cut air to the cooler. The original Spyders had this feature, controlled by a button or pull switch near the driver’s left knee. I couldn’t figure out an elegant way to install it in the ducts, however, so I dropped the idea for now at least.

The top piece is held on by #6 sheet metal screws. They’re long; I ordered short ones to replace them. And I can open up the system and put in a shutter later if I get ambitious. It would be redundant, as the car is going to have a thermostatically-controlled system that keeps oil out of the cooler until it warms up. But having that little flap would be kinda cool.

Next up: More Fun With Aluminum

 

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