We Kicked A**...
...and Phil took names!

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It’s been a busy week at ISOA challenge car headquarters. The construction of our propane powered supercharged GT6 for the Grassroots Motorsports $2002 Challenge is getting close to the wire but it looks like we’ll be ready in time for the event next week. Our resident autocross champion Mike Konopka has agreed to drive the car for us so Phil and I don’t have to embarrass ourselves on the course.

After constructing a new air box out of ¼" steel plate Phil Fox and I reassembled the engine the Sunday after the Big Bash but a fuel starvation problem prevented it from running for more than a few seconds. Later that week Phil replaced the bushings in the shift linkage. Before he put the new bushings in the shifter was so loose it took some careful jiggling to get the car into gear and you had to hope you got the gear you were looking for. With the new bushings everything is tight and the lever now slides into gear with a satisfying ‘snic’. If the transmission linkage in your Spitfire or GT6 is loose I strongly recommend pulling the transmission cover off and replacing these bushings.

During a marathon session on Sunday the 10^th Mike Konopka tore into the front suspension and replaced the old rubber with new polyurethane bushings from British Parts Northwest. Phil tackled the seized brake pistons and rebuilt the calipers.

The propane regulator has engine coolant flowing through it to help warm the liquid propane and convert it to gas. To solve our cold start fuel problem I moved the propane regulator from the battery tray to the passenger foot well to keep it below the coolant level in the radiator. I also piped in a cold start valve between the regulator and the carburetor. This valve acts like a choke by allowing propane gas to bypass the regulator and metering jet and go directly into the throttle body for a super rich mixture. Once the plumbing was complete Phil cranked the engine while I operated the throttle and cold start valve and the engine roared to life! The engine ran smoothly with good throttle response for a while and then the supercharger gasket blew out so we shut it down. Mike’s golden ears thought the engine sounded good and he commented "that didn’t sound like a Triumph engine!"

While replacing the gasket I noticed that a foreign object had found its way into the supercharger and was scratching the epoxy coating on the rotors and preventing them from turning freely. I tore the unit apart and found a tiny sliver of sheet metal that must have come loose from one of the sheet metal screws used to seal the intake air box. I cleaned the rotors, the supercharger housing and the air box before reassembly.

By Erik "Iceman" Quackenbush

Part 1 of 3 Part 2 of 3 Part 3 of 3

We Kicked A**... ...and Phil took names!

We Kicked A**...
...and Phil took names!