Hercules Engine News

Building a Cylinder Head


| January 2006



Exhaustside.jpg

'Above: The exhaust side, welded but without the band. '

Editor's note: This month, guest writer Kevin Pulver has written an interesting article on fabricating a cylinder head for his circa-1915 Champion. A very unusual engine, it was manufactured for Lininger Implement, Omaha, Neb., by Hercules and based on a 12 HP Model E.

The head (and most everything else) was thrown away when my 12 HP Champion was converted to a log splitter. I wanted to cast a water-cooled head as original, but foundry work was estimated at $3,000. It may have been a Gas Engine Magazine article about an engine totally made of steel and welded together that got me thinking about fabricating a head. I'm not a machinist, but after reading books and dreaming of do-it-yourself pattern making, sand casting and iron melting, this method seemed easy by comparison.

A God-given imagination let me see the plan before I ever made the rough sketches that were our prints. My wife, Maria, encouraged me to work on it when business was slow. Through Harry's Internet engine page (www.SmokStak.com), I met Joel Mosley three hours away in Omaha, Neb., who re-cast his rocker arm for me, and took me to measure his 12 HP Economy when I started work.

I should have kept track of time, but I would estimate the project took 80 hours. My friends Joe Dittrick and Bill Wehrman let me use their machine tools, and my brother-in-law did most of the welding.

We started with two 1/2-inch thick plates for the top and bottom. First, I tacked them together, and drilled the five head-bolt holes. Next, I located where the valves would center and drilled 1/4-inch holes. The intake port was made up of 2-inch gas pipe fittings. For the exhaust, I cut 3-inch pipe wedges to get the tighter radius necessary to fit the available space between the plates. My friend Bob Clark gave me the idea to first mock up the ports from PVC pipe. I remembered enough from watching Lyle Clemens build irrigation risers to get my pipe marked out. After a bit of trial and error with my DeWalt sliding compound miter saw, I knew the lengths and angles I needed and copied them in steel on the band saw.

I turned tapered valve guides from 1-inch round stock, drilled 1/4-inch. The two ports were drilled on the lathe and mill to accept the guides, and I used round centering plugs and 1/4-inch ready rod and nuts to jig them for welding. The same 1/4-inch ready rod was used to clamp the port/guide assembly to the bottom plate. Next, 3/4-inch steel pipes were lathe-cut to go over the head bolts and sandwich between the two plates. They would spread the plates and seal the water jacket. Slots were milled in the bottom plate to correspond to water jacket holes in the block.