Harley-Davidson Shovelhead engine

The Shovelhead engine was created as the previous Panhead engine was becoming obsolete, with many Harley-Davidson owners demanding more power to compete with the more modern motorcycles. With Harley-Davidson trying to fix the engine rather than research and develop, they fell far behind the competition of the cheaper and more reliable Japanese bikes taking control over the market. After realizing they would need some serious improvement to fix their current situation, they produced some updates in 1978 to the engine that consisted of a larger displacement, and steel struts cast into the pistons to prevent them from expanding from the heat. However, the changes were not enough for the declining quality of American fuel at the time. Valves and guides were prone to problems, along with more overheating, detonation, and oil consumption. Another problem that arose in 1979 was that the motors were fitted with electronic ignition units, which were prone to failure. Many owners would swap the units for an older point-ignition system for reliability. The larger compression ratio on the newer engines was still a serious problem, due to the low fuel quality and octane. With many Shovelhead owners having to turn towards aftermarket parts to keep the bike running properly, Harley-Davidson realized they would have to start developing a new engine. Towards the end of the Shovelhead's production, Harley-Davidson made numerous modifications in an attempt to keep the engine usable for production. Belt drive was added to their motorcycles in 1980 to prevent the oil leakage from the enclosed chain, along with a 5-speed transmission and rubber motor mounts to help reduce vibration. In 1981, Harley Davidson purchased AMF's share of the company back, adding a new oil pump, improved valve guides, and lowering the compression to help the engines run on the lower quality gasoline in the United States. The engine was produced until 1984, where the Evolution engine, which had aluminum heads and barrels, began to take over on most models. The engine could still be found in certain models such as the FLH in 1985, but was shortly replaced by the succeeding Evolution engine. == Usage ==

The Shovelhead engine was ultimately fitted to all of Harley-Davidson's big twin motorcycles throughout its production. The engines were first met with controversy due to the Shovelhead's weight and ground clearance. Because of this steering and weaving became a new issue that arose with motorcycles fitted with the engine. To bring more models into production, the FX Super Glide was released in 1971 with a "chopper" look that was ultimately an FLH with a Sportster front. This brought the motorcycle scene at the time to a broader audience and improved sales for the company. The FLH was also available with an Electra-glide package, which was used as a police engine for the motorcycles. It allowed the engines to turn over for a longer period while idling, along with having an electric start. Because of the added weight of the larger engine on motorcycles with the Electra-glide package, the bikes were faster and more powerful at the tradeoff of being much harder to maneuver. Due to the police package being a rarity, it is highly sought after by collectors. Today, the engines are commonly used by classic motorcycle enthusiasts for restoration projects due to the engine's simple transmission, high torque, and smooth powerband. == See also ==