Diamond T Grand Prix Truck

by Steve Walker

I keep doing drawings of cars. A lot of them featured Diamond T grills, because after building the first Diamond T Boat-tail Roadster, I still had one more grill to use. One design in particular caught the eye of Colin Case, an architect, art collector and yachtsman in San Francisco. “We need to build this” he said.

He wrote a generous check to initiate the project. Furthering the history of Diamond T racing, this would be the model succeeding the Boat Tail. It would be mid-engined, like the pre-war Auto Union Grand Prix racing cars and would have four wheel independent suspension. It would retain the distinctive, identifying grill and the long rear body would be crested with a large graceful tail. The straight sides would rest on fat side pods, given the car visual gravity. Overall, it would be at least as big as the big yellow Diamond T Boat-tail Roadster.

Like Lynn and I, Colin was a big guy. So I was not going to repeat the small cockpit – this would seat two huge guys with a cooler between them. There would be plenty of leg room and lots of storage compartments, as well. I wanted to sit high, with a good view of traffic.

I drew up a space frame with '60s formula car suspension, scaled up to truck size.

I sent Colin, who lived in San Francisco, drawings of the frame and body designs. He wasn't quite satisfied with the fin and insisted the engine needed to be a V-12. “You get it and I'll put it in”, I told him. But in the meantime, to prove the engine bay could accommodate the length, I installed a six cylinder 250cid Chevy truck engine. The engine and suspension arms bolt to aluminum plates. This was a technique I had seen on formula cars in the early '70s. It would also expedite the engine and transmission swap when Colin came up with his preferred engine.

As usual, I sawed up my work van for parts: straight six engine, front hub carriers, master cylinder and such.

I launched into the most laborious parts first, hand cutting and welding the frame, selecting hundreds of lattice boards and planking the body. Most important was to get the shape right, and I knew I could do that in wood. Later it could be the fiberglass form, if needed.

I crafted elaborate scissor action hinges for the engine bay doors by the time honored method of trial and error. Some salvaged Diamond T latch handles provided the appropriate detail on the doors.

Colin went to work selecting the color.

He sent a color chip, which in reality was an exquisite English made die-cast model of the "Chapman Special", second place finisher at the '55 Indianapolis 500. It was a lovely turquoise blue and as color chips go, it was a knockout. But, when Colin later visited Seattle, he spotted the model on my desk. “Is that the one I sent you?” Yes it is. “No, that's not the color. It looked better in the photo.” I think he meant the blue of the Blue Crown specials of '47 and '48.

Sadly, Colin died, an unexpected and abrupt death, before the car was done. He was a classy guy and devoted friend that I will sorely miss. At his wake, I shared pictures of our last, unfinished project.

Colin's death took the fun out of it for me. The car languished for some time under a tarp in a corner of my shop until I finally resolved that it deserved completion. So, in the summer of 2010, I stripped it back to the frame and dove in with renewed determination to see our car on the road.

My goal was the Tacoma Hot Rod a Rama; my favorite local car show.

I worked twelve and fourteen hour days as the show approached. Friends would drift in, get “Tom Sawyered” into the project and work to exhaustion helping me out.

For wheels, Trail Ready custom machined American cast billets to my specs.

The wood, I sprayed with four coats of varnish, adding just a tint of "Blue Crown Special" blue to the third coat which I feathered in along the fin, tail and edges.

I designed the upholstery and had Mobetta Shows stitch it together. Endless trips back and forth to hardware and automotive stores were made to find fittings and adapters to tie together all the disparate parts. Seat belts from the black Chevy van were installed, along with tail lights from Bent Bike, Harley rear view mirrors and, of course, Diamond T headlights. The headlights, on testing, worked just fine for about six seconds and then went dark. Of course! What a bozo move! In '48 they would have operated on a six volt system. I replaced them with modern 12 volt sealed beams and they are perfect.

I hired a sign painter, Sergio Nicoli, to paint number “523” on both sides (my wedding anniversary – "look honey, I built it for us!") as well as the classic Mobile red Pegasus.

I also had Sergio paint a prominent logo for “Colin Case Racing” on both sides of the fin and he produced “Close Enough Engineering” decals for the doors and “Diamond T” emblems for the cowling. He reported that when he looked up Diamond T on the internet, the first thing that appeared was a picture of the fictitious Boat-tailed Roadster, now more famous than the venerable truck company.

The night before the Tacoma Show, I struggled with leaking brake lines and power steering fittings. I replaced all and then maddeningly, the Chevy 10 brakes were frozen. In the shop, I scrounged a set of Chevy 20 brake calipers and ground them to fit. At 10 o’clock on the morning of the show, with the car just hours from completion, I conceded defeat and drove my Alfa instead. Later, bitter at having missed the show, my friend Greg Nowak ('31 Chrysler) put it in perspective for me: "Steve" he said, "when the biggest problem we have is which car we're driving to the car show, we're really not that bad off."

It was to be the last Tacoma Hot Rod a Rama.

The first show I actually got the GPT to was my new favorite, the Rat Bastards Infestation car show show at the XXX Root Beer stand in Issaquah, WA. Jennifer rode with me.

I made up a "history" of the car and the Grand Prix Truck Races that I framed and perched on the seat. Almost immediately, a fan began telling me that their great uncle had competed in the Grand Prix Truck Races.

The car was a hit at the show and garnered its first of many trophies.

Below is the history I have printed up and display in the vehicle at car show:

1948 Diamond T GPT

Commissioned by privateer Colin Case for the 1948 season of Grand Prix Truck racing.

Long distance Grand Prix Truck racing started up after the Second World War. Races were held on demanding transcontinental roads built to move men and material during the war such as the Alaskan Highway, Burma Road, Trans Siberia and Trans Sahara.

Sportsman – entrepreneur Colin Case, (an avid yacht racer who also sponsored formula and sports car racing teams, gravity racers, bicycle racing teams and a hockey club), decided to enter the wildly popular new sport of Grand Prix Trucks.

Colin selected Diamond T to fabricate his GPT racer. The premier truck manufacturer in the world from1911 to 1966, founder C. A. Tilt started out building race cars and established a reputation for innovation and reliability.

Colin commissioned an entirely new design inspired by the forward thinking pre-war Auto Union Grand Prix cars. His mid-engined vehicle features a welded tube space frame, independent suspension, power steering and a straight six engine.

After many seasons of hard campaigning followed by long neglect, this vehicle was in sad shape when abandoned in the Close Enough Engineering parking lot by the last owner, Charles Van Ness.

The ongoing restoration has stretched over years due largely to the shifty character and slack work habits of the occasionally paid personnel of Close Enough Engineering.


Original artwork by Steve Walker