Details, details

We had a deep freeze just after Christmas, so I came home to a really cold shop. So cold that I decided to clean out my office, paint it, install some shelves, work on my novel…pretty much anything but get back on the Spyder.

The weather broke a few days ago and I decided to take a break from the tub aluminum job and square-up my Autopulse 500 fuel pumps.

A little background: Autopulse was a Detroit company and they made, probably, millions of these heavy electric fuel pumps even before Walbro bought them in 1958 and moved the factory (and 30 jobs) From Ludington (where the company had previously relocated) to Cass City, MI. Very old cars got a model 300, and later (say, post-WWII) enjoyed the Model 500. Both looked the same, with a hand-sized squarish cover over a heavy coil and contact points on the bottom, flow-through 1/8-inch NPT fittings just above that, and a funky dome thing on top, which housed a filter screen. They were installed, alone, in pairs and sometimes even tripled, in every kind of vehicle from tractors to airplanes. Early Porsches got ’em too and, on the Spyder, they were something of a decorative focal point in the cockpit, a pair residing just behind the front fender, next to the driver’s left knee.

Here’s a closeup of a set—leaking, it appears—in a Spyder housed in an Australian museum. Thanks to Type550.com for the image.

Basically, if you look in any Renn Sport 1500 from the passenger side, these things just jump out at you. They scream: serious equipment. They whisper: race car.

Here’s a look at 550-0050 so you can see what I mean:

Hence my search for a pair.

Everything’s on ebay, and I picked up a couple for about $80 each. The first one, a black-crinkle-finished 12-volt model, ran steady when I hooked it to a battery. The pic below shows it hanging because I later took about 400 photos of it with the idea of having Shapeways print them out; haven’t got round to that yet.

The copper bellows appear to be intact too; I suspect it works.

Later I scored an older 6-volt model. You can tell the difference because the fingernail-sized leather tab insulating the positive terminal say “6V” instead of “12V.”

I guess $160 for a pair of decorative fuel pumps seems steep. I did to me. And getting these things working can be quite expensive—they being Porsche parts and all. (That’s the cheap outlet).

But the hard part isn’t the pumps. Millions were made. The hard part is the manifolds to connect two together. Those are basically a Porsche-only thing, they haven’t been made in years. The Spyder replica guy responsible for the Type550 site had a batch cast about 10 years ago. They sold out instantly at $300 a pair, and that did not include the thin banjo bolts to attach them to the pumps. He said those would likely cost another $300.

Something close is sold here for but $16.50. Those would probably work, though they’re a bit thicker than the originals (probably to stop leaks) and only 9/16 heads instead of the original 3/4.  I wish I’d seen them before I made my own.

To make the manifolds in-house I first estimated the size, then searched around the garage for likely bits of pipe. Came up with a bit of copper pipe from the long-ago airhose installation, a bit of conduit, and some half-inch aluminum tubing. I couldn’t find any kind of bolt or nut with the right kind of head, so while at Home Depot for another chore I browsed around until I found these.

Something like $6 for a bag.

Next: cut, drill, gouge, etc.

 

Getting the manifolds attached to the pumps took some ingenuity—mainly because I did not have a 1/8-inch-by-27-thread die. I found a couple of old Subaru exhaust manifold bolts that would go in about a a turn and a half before locking up. And I had a 1/8 NPT insert that would screw in all the way. But neither offered a good way to attach my newly-made junk.

So I got some smaller taps…

et voila!

Started the “restoration” i.e. wire-brush the old paint off the crappier pump.

Put the NPT inserts in the other side and filled them with “Quick Steel” epoxy.

Then marked the pipes for holes so I could screw them on.

Drilled. Of course I missed center…

Opened them up and got everything more-or-less together.

From here is was fettling. More epoxy, shape with the Dremel, etc. I did spurge on a set of number-letter stamps to fully counterfeit these things.

For the record, that’s the wrong patent number. And, of course, everyone knows the letters should be raised, as in cast-in, not stamped.

It was warm yesterday so I painted.

A word to the wise: if you’re painting with anything tolulene or acetone based, don’t set your work on a piece of styrofoam.

They came out fairly lifelike.

Now here’s the trick: I’m mounting the real fuel pump behind these. It’s a Carter rotary pump the VW guys swear by. Since the Autopulses mount on a “box” (on the real Spyder it was a stiffening element for the body), I just have to make an access cover to get behind it. Then I can run my fuel line into that, loop it over the real pump (with a filter and cutoff valve), through the pump and back up and out through the “box” under the door.

The best part: when I turn the key switch, the fuel pump will whir to life—the sound seeming to come from my dummy pumps. The only downside: if you know what a working Autopulse sounds like, you’ll know that ain’t them.

I decided to use rivet-nuts and machine screws rather than sheet metal screws to hold the plate on.

And there we have it. For a measly 17 hours of labor, plus $200 in parts (including the functional fuel pump and filter!), the unit is now ready to be installed. I guess I’ll paint the cover plate body color to match the rest of the interior first.

Now back to riveting…

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