Shovelhead isn’t Harley-Davidson’s most powerful motorcycle engine, but it had a successful run from 1966 to 1982. Unfortunately, time more or less ended the Shovelhead engine’s reign. However, it wasn’t the same situation as the Panhead, which ultimately wasn’t strong enough for modern motorcycles. Instead, geopolitics marked the end of the Shovelhead.
In 1974, the ramifications of the ongoing oil crisis began to take effect, resulting in fuel scarcity. What gasoline was available had a lower octane number which made it less stable and consistent, bringing a slew of problems to engines worldwide. With the Shovelhead, the low-quality fuel resulted in engine knocking which then caused overheating. As the engine got hotter, the aluminum expanded and oil leaks quickly became a problem. Unfortunately, American Machine and Foundry, the owners of Harley-Davidson at the time, decided to continue production without addressing the engine’s issues.
It didn’t take long for oil leakage to become a serious problem for the Shovelhead. In fact, it was so bad that it overshadowed everything Harley-Davidson had accomplished with the engine, earning it a notorious reputation. It was eventually replaced by the Evolution engine. Today, the oil leak problems are arguably the most well-known aspect of the Shovelhead.
