Pistons took a pounding at Le Mans in 1976

John Todd from Seattle recently got in touch with us. That may not seem worth mentionning to you, unless you know who he is. John Todd was working at Precision Engines and assembled the 426 Wedge engines for the Charger in 1976. He was also a member of McGriff's pit crew at the Le Mans. You bet that we called him right after reading his e-mail. Here is what John told us about the Chargers engines!

The Charger was shipped to France with a 426 HEMI in its engine bay (which confirms what Dick Pierson told us previously) and then fitted with a 426 Wedge at the race. While the HEMI was probably used for the first free practice at Le Mans, runnning on the race fuel that was still in the Chargers tank, qualifying and racing was to be done with the wedge V8. The Wedge was preferred to the HEMI for its lighter weight. The HEMI had a 13:1 CR and the wedges were purposly built for 93 octane gas with an 11:1 CR. John got 630 hp at 6200 rpm out of the 426 wedge V8, using premium pump gas. So far, it all looked great, but there was a technical misunderstanding that was only discovered once the Charger ran at Le Mans. Due to different ways to measure octane in the USA and in France, french 93 octane translates into 88 octane in America. This caused the engines to pre-ignite badly, as you can see on the pcitures of the melted pistons. John kept two of those as a souvenir from Le Mans and was kind enough to photograph them for our website. After the first engine blew in qualifying, John and Orv Rupp, Precision Engines boss, discussed on how to "band-aid" the second engine. Fitting multiple head gaskets or milling down the pistons was discussed in the pits. Even sneaking in octane booster was considered, but shuned for reasons of sportsmanship. In the end, the team decided to richen the mixture and retard timing as much as they could, since they did not want to mess with the engines internals in the pits of the Le Mans racetrack. This allowed to last for around 20 miles of racing, before the pistons of the second engine melted too. Hence, the Charger, as you all know, lasted less than three laps! Thank you, John, for sharing your Le Mans experience with us !