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Before and after the intake manifold explosion.
If there’s any doubt that valvetrain failure leads to most engine explosions, take a look at the hood and Hogan intake manifold of Scott Oksas’ Pro Mod car. The gaping holes in both the carbon fiber bodywork and aluminum metalwork are the result of a stuck intake valve in the middle of the run.
“It was between the two-three shift,” remembers Oksas, who was racing at a West Coast Pro Mod Association event in Bakersfield in late March. “It was like a giant bomb going off.”
A stuck intake valve led to the explosion that ripped the top of the manifold right off and tore up the carbon fiber bodywork.
The data recorder reveals the 485ci BAE engine was turning just a shade under 10,000 rpm and the twin Precision Turbos were delivering 56 pounds of boost. When the valve stuck open, that left a clear pathway for an ignition spark to travel from the No. 2 cylinder through the intake runners to the plenum, and boom! When the safety burst panel failed, the pressure had only way direction to go, and that was up. Sad news for the distinctive artwork that we noticed last time EngineLabs checked in with Oksas.
Scott Oksas talks to a fan during the recent race at Fontana. On the right is a current photo showing the repair work.
At the time of the explosion, Oksas had just crossed the eighth-mile lights with a time of 3.96 seconds at just over 200 mph.
Jaime Voorhees at Fab-Tech Custom repaired the plenum and fabricated a new top plate and burst panel. Crew chief Bill Hickok, who provided photos of the destruction, and Keith Stone worked on the car the following week to get it ready for the NMCA West Spring Nationals meet at Fontana, California, the following weekend.
Scott Oksas in action at the NMCA West Spring Nationals, sporting a new paint scheme since the last time we checked in with the team.
