A 'Lazarus' Project

A 1/2 HP Maytag Raised from the Dead

| October 2005

  • 1_2HPMaytag.jpg

  • ReboringtheCylinder.jpg
    'Reboring the cylinder, showing the holding jig. '
  • NewPiston.jpg
    Machining the inside of the new piston made for Maytag serial no. 30202.
  • BrokenCoolingFins.jpg
    Repairing the broken cooling fins with sandwich bags and JB Weld.

  • 1_2HPMaytag.jpg
  • ReboringtheCylinder.jpg
  • NewPiston.jpg
  • BrokenCoolingFins.jpg

Last April, a friend presented me with a challenging problem - a 1918 1/2 HP upright Maytag with a very stuck piston. The piston resisted all conventional removal methods: heat, hydraulics and, finally, a cable doubled around the wrist pin that succeeded only in removing the wrist pin.

Extreme Extraction

I began by mounting the cylinder on an angle plate on the mill, and used a hole saw to remove much of the interior of the piston. A boring head thinned the piston wall until I could peel out the remains with an ice pick. Fortunately, enough of the piston remained so I could obtain dimensions for future reference.

The cylinder was badly pitted, so I used a larger boring head to oversize the bore to 2.030 inches. The cylinder was further stabilized while machining by screwing a 1/2-inch pipe plug into the spark plug hole, clamping the pipe plug in a vise and clamping the vise to the mill table. Of course there was some tool chatter, and the bore tapered down to 0.005-inch smaller at the head. I don't have access to a blind hole or precision hone, so I used what I had available and began lapping the cylinder bore with successively larger cast iron discs. I used a non-embedding compound with the discs and got the cylinder in much better condition.

From 2-1/8-inch gray iron stock I made the piston and rings. I left extra stock length on the piston head to use as a tailstock live center while cutting the ring grooves. The finished piston was also lap-fit with the same non-embedding compound used on the cylinder.

First, I cut the rings from the same gray iron bar, then cut the grooves in the piston to fit. The rings measured 2.060 inches outside diameter prior to installing them. I cut the diagonal gap, then spread and heat treated them. I then pushed the ring up to the exhaust port to check and adjust the gap.

I made a plug to fit snugly in the cylinder; then, using a ball in the 1/8-inch pipe plug hole in the cylinder as a set screw, I trimmed the cylinder base flange perpendicular to the bore. I finished the top of the piston with a band saw, belt sander and ball end mill.


Gas Engine Magazine A_M 16Gas Engine Magazine is your best source for tractor and stationary gas engine information.  Subscribe and connect with more than 23,000 other gas engine collectors and build your knowledge, share your passion and search for parts, in the publication written by and for gas engine enthusiasts! Gas Engine Magazine brings you: restoration stories, company histories, and technical advice. Plus our Flywheel Forum column helps answer your engine inquiries!

Be sure to take advantage of the Square Deal Subscription Program.

  • No Missed Issues.

  • No Renewal Notices.

  • No Additional Cost.

The Square Deal Subscription Program is designed as a paperless transaction with automatic renewals at a preferred low rate.   With advanced electronic notification, a 100% satisfaction guarantee and an easy opt-out plan, the Square Deal Subscription Program is the best value, risk free, eco-friendliest way to subscribe.

Facebook YouTube