Scratch-Built One-Off Wonders
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“But I looked at the humongous pile of rocker arms, pistons, shafts and everything else, and figured I had too much time in it already,” he says, “so I had to finish it.”
No method of sealing the pistons worked until he created steel pistons and welded them to the shaft. Bingo! “Now water runs through the shaft and piston as it should,” he marvels, “and the engine starts on the second turn every time.” Mark figures he has 2,000 hours of labor in the project.
A machinist’s mind
Mark knows how big the pieces on his engines need to be without measuring. “With that 500-cubic-inch one, for example, I know how much clearance a piston of 8-by-10-inch bore and stroke requires,” he says. “The sleeve and piston are steel with similar expansion rates, so I insert the correct amount of clearance between the piston and the cylinder sleeve.”
While making bearings for the 500-cubic-inch engine, Mark found himself laughing as the molten metal being poured into a mold made a “glug glug” sound like that heard when filling a Thermos bottle. He uses an old bearing knife to hand-scrape each bearing to the proper size.
He also makes the molds and generally cuts his own gears — except for two, because he didn’t have the proper equipment. “My wife, Marlene, has been very patient with me,” he says. “I showed her some gears and said, ‘Honey, I can buy these for $40 each, but if you let me spend $3,000 on a machine, I’ll be able to make them myself.” She said he could buy the machine.
One thing he doesn’t make: flywheels. “I find them at swap meets,” he says. “They come from old engines and I adapt them to my needs.” Most flywheels are built to balance the engine. “I have to make the flywheel have neutral balance on a shaft,” he says, “and clean the bore so it fits the engine.”
Mark’s engines — one small enough for a single person to carry, the largest weighing 2,300 pounds — have powered corn shellers, a dynamometer he built, a blacksmith’s line shaft and a 3 kw generator. He ran the 5 hp engine on a series of progressively larger corn shellers until it worked faster than three men could scoop. “The corn plugged the sheller, killed the engine and everybody cheered,” he recalls.
His engines get a lot of attention at shows. “People are amazed somebody could take a pile of steel and make an engine that runs,” he says. “Well, it needs fuel, it needs compression and it needs spark. You just break that down into how much fuel, how much compression and when to make it spark. It’s really simple if you go about it methodically.”
He’s amazed at how people follow him. At one show, when his 4-cylinder Snow got hot, he shut it down, telling a group of onlookers who’d just arrived that he wouldn’t start it for another three hours. “That’s when they showed up and I ran it again,” he says. “It’s humbling that people care that much about what you’re doing.”