Using the Hydraulic Method on a Headless

Using a grease gun and the hydraulic method to free the stuck piston on a headless 1918 1-1/2 HP Fairbanks-Morse.

| June 2007

We reached a roadblock in the restoration process of my 12-year-old son Steven's 1918 Fairbanks-Morse headless 1-1/2 HP engine. After careful and complete disassembly of the rusted mass (or should I say mess?) of iron, we had been unsuccessful at freeing the stuck piston.

Soaking with Kroil, fuel oil, WD-40 and pounding (gently) on the exposed piston skirt had yielded no sign of movement. With no cylinder head to remove to gain access to the top of the piston on which to pound/press it out, options were few.

We decided to try hydraulic pressure. We fabricated a steel plate to cover the igniter opening. Nothing high-tech here, just a scrap piece of 3/8-inch plate in which two clearance holes were drilled to go over the igniter mounting studs. Halfway between the stud holes we drilled and tapped for the installation of a zerk fitting.

Steven then made a set of new gaskets. We laid the engine on its side, installed the mixer casting and exhaust valve. I then filled the cylinder with fuel oil through the igniter assembly opening to displace all the air in the engine. Steven installed the zerk plate and began pumping the cylinder full of grease with the grease gun.

Unfortunately, we found the new gaskets oozed and fuel oil was leaking past the exhaust valve. We could not build any pressure with all the leaks. We did not have a problem with the intake valve since it was still rusted tightly in the mixer casting. I didn't want to mess with valve seat machining since the cylinder might also need machining. And I did not want the engine possibly going to the shop twice! What to do?

Since heat would not be an issue I decided to make another set of gaskets out of an old inner tube. I also made a rubber washer to install on the exhaust valve. I found a stiff spring to put on the exhaust valve stem to pull the valve tight, thereby pinching the inner tube washer tightly between the valve and seat.