The 25¢ Valve

Turning a Swap Meet Valve Into Something You Can Use


| January 2005



Photo_1.jpg

'Photo 1 : Cheap valves like these are easy to come by, so it won’t matter if you make a mistake. '

Most engine people have had an engine with rusted, damaged or missing valves that needed replacement. A slow-running show engine can get by with a lot of problems, but when a part is missing or unrepairable, the engine is shut down. If you are lucky and have a common engine you can order a new valve, but the price will be $20 to $35 each. If you have something rare, the price is "contact us for details." You can bet it'll be over $35. But there is another way to replace valves for engines of this type.

Finding Valves

At the next swap meet you go to, just look in the junk parts boxes. You should be able to get a handful of old, unidentified valves for a quarter apiece or so. I look for valves with stems around 3/8-inch, which is a good size for most of these engines.

Photo 1 shows an original Nelson Bros. valve with a burnt spot at the arrow. The other valves came from unknown engines. The one on the left has a stem that is too small. The one on the right is too large. The last one, as Goldilocks said, is just right.

"Just right" means the stem is the same diameter as the original. The head is too large and the stem is too long but those problems can be fixed. If you use the original valve as a pattern and trace the size of the new valve with a Sharpie as shown in Photo 2, you'll see how much material has to be taken off.

Photo 3 shows the valve chucked up in an electric drill and being ground down on a grinding wheel. A lathe is not needed, as exact precision is not necessary. Just grind until the entire Sharpie mark is gone and you will have the correct diameter as Photo 4 shows. Of course the rim is too thick and there isn't enough face area. Just hold the drill at a 45-degree angle and grind off enough for a proper face angle. It is better to use a fine wheel than the coarse one I used, but it worked.

The stem is still too long and is hardened. Mark the proper length and heat that spot red hot as in Photo 5. Cool slowly to anneal. Now it can be cut with a hacksaw. Drill a 1/8-inch hole in the tip for the cotter pin and your valve is finished.