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Monday Edition


Transform Your Shovelhead Into An Evo

Give That Shovel A Chance At Reliability And Performance

By Wrench, Photos by Sin Wu
6/30/2004


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Deacon

Deacon, the master, taking a break. Photo by Chris T.

I ran across a master mechanic, in Oahu, Hawaii, at Pro Street, who recently produced the first Choppers Only Show in Wakiki. He explained the differences between the Evolution configuration and the Shovelhead and how you can alter your Shovel for reliability and better performance. I was intrigued, grabbed my camera girl and went after the formula.

side of flywheels

Note the heavier/thicker Shovel wheel.

First off the flywheels are 4 pounds lighter, saving 8 pounds off the lower end. That's 8 less pounds the engine is forced to lug around.

"You can go either way with the flywheels," Deacon said, "although it's easier to just swap them. The new set will already be correctly clearanced and have a better rod package. Sets can be ordered from S&S in this configuration."

piston comp.

This shot shows a performance flat top job, a standard Shovelhead piston and a Sportster unit. Imagine the spark trying to climb over that Sportster piston dome.

Next, Evolutions use flat-top pistons for an immediate burn. Shovelheads are equipped with domed pistons and one spark plug. The flame must travel up and over the dome. That can be corrected with two plugs, but a better way to go is to use the flat-top piston configuration like Evolutions.

"Compression ratio is based on how the bike will be ridden and how much HP is desired," Deacon told me. "Use flat top pistons or J&E 30 degree entry pistons with S.T.D bathtub chamber heads."

valve comp.

Here's a shot of the heavier Shovelhead valve on the right and the lighter stem larger Evolution face for better flow.

The valve train in an Evolution is lighter with smaller shaft diameter valves with a larger diameter face for better flow and volume. "Use Kibblewhite or Manley thin stemmed valves," Deacon muttered and went back to work.

stem keeper set

Keeper kit from Precision Machine.

A company called Precision Machine offers a conversion kit to use Evo valves in your Shovelhead. "The kit contains the keepers to use Shovel upper collars," Deacon added. "Also use cast iron valve guides from Rowe for your specific application."

shovel lifter, valve and block

Here's a goddamn stock Shovel valve, lifter and lifter block. An Evo unit will fit right in.

The hydraulic lifters in Shovels are weak and oil poorly. The Bolt pattern for Shovels and Evo lifter blocks are the same, so you can replace the Shovel lifter blocks with Evo units and a much larger automotive type lifter to improve valve train operation.

evo lifter, valve and block

Here's the updated Evo valve train configuration. It will bolt right in.

Deacon likes S&S oil pumps and doesn't much care for JIMS replacement lifters. "Yes, use an S&S oil pump," Deacon snapped and raised a large torque wrench in my direction. "You will get more volume for better top end oiling. With more volume you need more scavenging and the S&S pump delivers this as well. Also, Baisley offers an overdrive pump gear to provide even more pressure.

lifters

A comparison shot of a Shovelhead and Evo lifter.

With the above mods your Shovel won't work so hard to spin those heavy flywheels and the valve train will be lighter, more proficient and flow more fuel, air and exhaust. The pistons will fire more efficiently and won't be subject to as much heat. The only aspect of the Evolution that you might miss will be the flow ability of the head design.

That's it, build a Shovel that will last. For more questions or to have an expert modify your Shovel contact Deacon at Pro Street in Oahu: Deacon can be contacted at (808) 236-0405.

c/o The Hogpen
94-084 Leokane St. #B
Waipahu, Hi. 96797

Ride Forever,
--Bandit


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Reader Comments


1200 Shovelhead wanted to go to flat top pistons, can I keep stock heads. I am going .020 over stock going to be daily rider might put mild cam in it what pistons should I go with.

Joe
College Park, MD
Friday, February 10, 2012
Editor Response I don't believe the flat-top pistons will would with Shovel Hemi heads, but I'm checking.
--Bandit

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