In the 1980s, many race series were experimenting with turbochargers on stock block and specialty race engines. Huge horsepower and torque numbers could be produced for a short period until the engine self-destructed. What a lot of the engineers and engine builders could not see was at peak cylinder pressures the head was distorting the casting and allowing combustion gases to get in between the head, gasket and block. New technologies like direct injection, variable valve timing and turbocharging are pushing chamber pressures far beyond what they were a decade ago. Head lift is not the whole head that is lifting from the block, but is a distortion in specific areas of the head and block interface where the head gasket is installed. This distortion can damage the head gaskets and head bolts. It is not a constant running condition, but occurs in milliseconds under the high-stress conditions where the greatest combustion chamber pressures are experienced. As the incidents of head lift add up, the head gasket and fasteners will be fatigued and eventually damaged.
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