Harley-Davidson Panhead Engine

Miami Chopper Shop

Harley-Davidson Motorcycles for Sale

Our design or yours, we build 'em!

The Harley Davidson Panhead Engine

The Last Panheads, The First Button Pushers

Harley-Davidson Overhead - Valve Twins

Harley-Davidson Hardware

Harley-Davidson Glides

The Panhead Era

Harley 1%ers vs. The Nicest People - The 1950s

Harley-Davidson Dressers vs. Choppers-The 1960s

PANHEAD * 1948 - 1965

The Panhead engine name introduced in 1948 came from its chromed steel rocker covers which resembled inverted baking pans. From 1949 on, the rockers were stainless steel.

The Pan was built with 61 and 74 cubic inch engine displacements, but the 61" was discontinue in 1953. The engine changes included:

the Knucklehead cast iron rocker covers were replaced with aluminum alloy.
new rocker gear and hydraulic lifters replaced the noisier solid push rods.
a revised and less leaky lubrication system.
new camshaft
larger capacity oil pump
untidy external oil feeds were replaced with internal ones

The new aluminum heads improved engine cooling and was 8 lbs. (3.6 kg) lighter than the Knucklehead. The spark plugs and bolts were threaded into steel inserts instead of the softer aluminum of the head itself. Early Panheads had about the same power as the Knucklehead - around 50 bhp at 4,800 rpm for the 74 cubic inch motor. In 1953 the valve lifters were relocated from the top of the push rods, placed to lie between the cam lobe and push rod in the timing case. Both crankcase valves greatly modified for better oil control. In 1956 the Panhead gained around 5 bhp with the introduction of a more free-breathing air cleaner and a high-lift "Victory" camshaft. Almost at the end of the Panhead, the engine reverted to the Knucklehead's external top end oil feeds to prevent overheating.

The famous "Glide", which was the first Harley-Davidson to use hydraulically dampened telescopic front forks, was the 1949 Hydra Glide. The Panhead engine powered the very first of the Electra Glides.

THE POPULARITY OF THE HARLEY-DAVIDSON PANHEAD MOTORCYCLE

Not long ago you could buy a running Harley-Davidson Panhead motorcycle for a few thousand dollars. Most of these were considered to be old motorcycles that leaked oil, didn't handle well and ran poorly. However, the "Captain America" Chopper used by Peter Fonda in the movie Easy Rider (1969) had a Panhead engine, as well as the bike ridden by Dennis Hopper.

Currently, a number of third-party engine manufacturers produce custom Panhead-style engines in a variety of bores, many much larger than the original displacement designs. Each manufacturer includes significant subtle upgrades to the original design to drastically improve the performance and reliability while still providing the original styling and overall engine structure.

The Panhead engine was the second Harley-Davidson overhead valve engine introduced in 1948 and continued to be the powerhouse until it was replaced with the slightly refined Shovelhead in 1965. The Pan replaced ther Knuclehead engine Harley-Davidson had used since 1936. Its quieter, yet throaty shound quickly became popular.

Just as the Knucklehead and later the Shovelhead were named for the shape of their rocker plate covers, those on top of the cylinders heads of the Panhead looked much like large flat pans. The Panhead was not much different from the Knucklehead. The major changes were the aluminum heads and the quieter, more efficient lower end. The change to hydraulic valve lifters took up any slack in the valve train automatically and relieved the need for more continual valve adjustment, which contributed to reduced engine noise and maintenance.

The impetus behind the development of the Harley-Davidson Panhead was the need to resolve oil leak issues experienced on the Harley-Davidson Knucklehead Engine. The Knucklehead had made the total loss oil system a thing of he past by introducing a recirculating oil system, but they continued to have oil leaks. The problem was solved by placing the external oil lines inside the engine casing, and the oil pump was upgraded to better regulate oil pressure. The new aluminum heads provided cooler engine performance. Some minor oil pressure problems persisted despite these improvements on early Pans, but this was eventually taken care of on the later models.

The Harley-Davidson Hydra Glide model had a Panhead engine mounted into a Harley frame with hydraulic forks which replaced the former Springer forks. The Hydra Glide was the basis for the later Electra Glide with a Shovelhead engine. It can be difficult to differentiate between the frames manufactured for Knucklehead engines and those for Panheads. There are major differences, but only a few are easy to spot. A Panhead engine can be very difficult to install into a Shovelhead frame, whereas a Shovelhead engine into a Panhead frame is easy. Knucklehead frames have straight down tubes, while the rigid Panheads are visibly slightly bowlegged. The early 1948, late 1956, and the 1957 Panhead frames also had down tubes that were straight. On these models, look for the triangular top motor mount on the Panhead frame.