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The Harley-Davidson Shovelhead Engine Harley-Davidson
Motorcycles for Sale Our
design or yours, we build 'em!
The first Shovelhead engine maintained the Harley-Davidson
method of bolting a new top end on to the proved crankcases developed from the previous generations of Panhead engines ending in 1965. The 1966 Electra Glide was the first Harley-Davidson to carry the Shovelhead engine.
The bottom end was that of a 1965 Panhead with the external oil feeds reintroduced in 1964. The name came from the descriptions given as looking like the backs
of coal shovels. The top end was all new, including alloy cylinder heads and iron cylinder
barrels. The pressed steel of the Panhead engine rocker boxes was replaced by a light alloy. The Shovelhead engine replaced the bottom end in 1970 with a crankshaft-mounted
alternator, making the engine wider. During this change Shovelhead engines were referred to "generator" and
"alternator" Shovels, later recognized as "cone motors" because of their cone-shaped cover on the right
side, allowing the external ignition points assembly to be moved inside the timing case. The timing gears were also
simplified. The Shovelhead engine was first offered with a displacement of 74 cubic inches (1,207
cc), and grew to 80 cubic inches (1,340 cc) in the 1978 FLH-80.
SPIDER'S
BIKER WEB HIDDEN VIRTUES OF THE SHOVELHEAD MOTOR The Harley-Davidson Shovelhead motor went out of production in 1984.
The motor has always had a bad rep (by some, not all), probably because it was the motor that AMF bought when it bought the
Company in 1974. The "The AMF Rescue of Harley-Davidson" years are viewed as a time when quality control went out the window. But is the bad reputation deserved? Aren't there some positive reasons one might run a Shovelhead motor?
First the obvious differences between the Shovelhead and the Evo. - Tolerances: Overall the Evo is machined to one thousandths inch where the Shovelhead is machined to five thousandths.
- Cylinders: The Evo design uses an iron core encased in aluminum casting where the Shovelhead is cast iron throughout.
- Headbolts: The Evo uses long bolts that extend from the case to the top of the head, where the Shovelhead uses two sets of shorter bolts - one
set to secure the cylinder to the case, and the other to secure the head to the cylinder.
There are many other differences, but those presented here are perhaps
the most significant. Shovelheads can be constructed to be more powerful and more reliable than any Evo. Many racers prefer the Shovelhead because it is easier to modify and capable of tremendous extremes of operation.
You can get an incredible variety of specialized parts, including high performance cases, pistons, valves, heads and cams
for Shovelheads. The engine ain't dead by any means, and is considered by many to be the best motor Harley-Davidson
ever made. In racing applications, Shovelhead cylinders distort
less than Evo cylinders because the Shovelhead jugs are made of cast iron. When under extreme stress, Evo cylinders (made of aluminum) tend to change their shape due to the unequal stress distribution around the head bolts.
This results in "blow by" between piston rings and the cylinder wall, and a reduction in power that gets transferred
to the pistons. This is a major reason for the desirability of Shovelhead motors in racing. Although the Evo has higher tolerances, the Shovelhead can be worked on in a home garage without the need for high tolerance machine tools.
In this respect, the Shovelhead is the last Harley-Davidson motor to be designed for the farm hand. You can wrench the
whole thing yourself! (With a little experience) The Evolution
engine has earned a reputation for being more "reliable". In reality, the Evo is indeed little more reliable, but a poorly maintained Evo will be much less reliable than a properly maintained Shovelhead. The difference is that when the Evo gets out of whack, you probably wont be able to fix it yourself. You
don't need to remove the Shovelhead motor from the frame to remove the heads of jugs. This means you can inspect and
replace valves, guides and heads as necessary. You can even hone your own cylinders! The Evo may be more "reliable" but it is closer to the philosophy of "no user-serviceable parts inside".
The twin-cam 88 is even less user-serviceable. You need lots of special tools to work on any Harley-Davidson motor after
the introduction of the Evo. So, you may need to change oil more often, and re-torque bolts, and
deal with wear in your valve guides, but you can do these things yourself instead of paying and expensive company mechanic.
If you are of the philosophy that a big part of riding is being constantly, intimately aware of how the bike is functioning.
You may find a good set of tools and a well set up Shovelhead is just the ticket. Bottom line is what you do when you're
stuck by the side of the road and can't take anything apart with limited tools. Evo riders wait for the tow truck. Shovel riders can unbolt stuff and make repairs.
The Shovelhead Era
The Harley-Davidson Shovelhead engine is proudly owned by
many custom chopper owners. The V-Twin engine was manufactured by Harley-Davidson from 1966 to 1984,
bringing refinements to the Knuckles and Pans. The Shovelhead engine took off from the Panhead desing with a different
look. As with the Knucklehead and the Panhead, the Shovelhead name was derived from the appearance of the rocker covers, resembling the head of inverted coal shovels.
The Shovel engine does not have rocker covers, but rather rocker boxes and rocker arms which pivot on shafts. It has
a more unique look and is slightly more powerful than the Panhead it replaced. The Shovelhead engines ended with the
introduction of the Harley-Davidson Evolution engine in 1985. Originally designed for
Sporsters, the Panhead began to lose popularithy as Harley owners began to demand more horsepower and Harley-Davidson responded with the Shovelhead
engine. Controversy arised from the added weight of the new model, and even today, some dealers in classic motorcyycle
parts distance themselves from the Shovelhead configuration, feeling it is slightly slower and less powerful than other models. In spite of the controversy, by the mid-1960's, the popularity of custom Choppers began an early peak. The new top end provided the power and acceleration the custom bike builder wanted, but the Shovelhead
engine's weight and proximity to the road did affect the steering somewhat. At high speeds, custom Choppers would begin to weave.
It is noteworthy the Shovelhead engine powered the Harley-Davidson
FLH Electra-Glide which included electric start. The "Glide" was THE motorcycle of choice for police and other agencies during its production and setting the stage for the movie "Electra-Glide in Blue" with Robert
Blake as the police officer who rode the Blue Glide. The FLH Electra-Glide package also allowed the engine to turn over
longer while idling. The electric starter was originally designed for marine engines and
became a great improvement for those riders who tired of kick-starts. With this change, more women began to ride, further
boosting the biker culture. The addition of the electric starter added only 10 lbs, but it's a great trade-off to starting
a cold engine. It's unlikely to find a Harley-Davidson Shovelhead engine with the original FLH Electra-Glide package,
making it very rare and prized by motorcycle and chopper part collectors.
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