A Shop Built 4 Cycle Gasoline Engine

(Video at the bottom of the page)

This is an internal combustion engine I built sometime in 2001-2002.  It
took me about three months to build it evenings and weekends.  At the time,
I had a job where I spent much of my time driving, and I thought about this
thing a lot.  I didn't draw up any proper plans for it, but did a number of rough
sketches with notes about what would bump into what, and which way things
should turn.  The size of the engine was dictated by the largest piece of
aluminum round stock I had on hand, (and that would fit in my little lathe), and
I made everything else to fit the crankcase, more or less.

It has a 3/4" bore and a stroke of a bit over one inch.  It has only
one compression ring, which I made from cast iron pipe.  The cylinder
is leaded steel, and the cylinder and head are a unit.  The intake valve is
atmospheric, exhaust operated by a cam driven off the crankshaft.  Timing
gears were made on the lathe.  Everything was made in my little shop except
for the ignition parts.  The coil is from a motorcycle, the points and condenser
from Volkswagen, and spark plug from Champion, just like the big boys.

The valves run in the aluminum pocket block on the top front of the engine.
They, (the valves) were probably the most time consuming thing on the engine.
I made a piloted cutter for the valve seats and cut the valves themselves on the lathe.
Then... Lap, lap, lap.

It runs best on Coleman lantern fuel.  It idles at about 100 rpm, and I'm
guessing when I say top speed is about 400 rpm.  It doesn't go very fast,
but I didn't build it to race. 

Here's a good shot of the valve pocket.  The intake valve is
directly over the exhaust valve.

The little hole in the back crankcase cover is the crankcase vent.

In this final shot you can see the the exhaust valve stem, the push rod, the camshaft,
and also the cam that opens and closes the points.

Here's a video of the engine running:
(turn up your sound)

More Taig lathe projects

(home page)

Copyright  Dean Williams