Assembly Instructions

Tools:

5/32” hex driver

1/16” hex driver

0.050” hex driver or key

Deburring tool

Small shop press

Place the burner tube in the groove in the rear half of the base. The flared end should be on the base side of the tube.

Place the front half of the base over the tube. Align the obround alignment pin with the corresponding pocket on the rear base half.

Press the front and rear base halves together. A small press may be helpful to force the burner tube into the slot.

Insert the 10-32 x ¾” cap screw into the counterbored hole on the back of the rear base.

Tighten with the 5/32” driver.

If the halves of the base to not pull together tightly, the burner tube may not be fully seated in its groove. See previous press step.

Place flywheel on the flywheel boss on the rear base. The boss should be a sliding fit with the flywheel bearing.

Rotate the flywheel so that the 4-40 tapped hole in the boss aligns with the access hole in the flywheel.

Insert and tighten the 4-40 x ¼” cap screw through the access hole. Use the 1/16” hex driver. The screw retains the flywheel by bearing on one edge of the inner race.

After tightening, the flywheel should run true when spun by hand. Some wobble in the bearing is expected, but the flywheel should not run out or display rigid, consistent, out of plane motion. If it does, it is likely that the bearing is not seated in the flywheel.

Install 4-40 pointed set screws in the base. These will form the cylinder pivots.

Insert the set screws with their pointed ends directed toward the centerline of the base. The point should just protrude past the inner surface of the base. Later we will direct them into the dimples on the cylinder pivot ring.

These screws should run freely without binding.

Set the square seal into the ring groove on the cylinder.

Next, slide the round o-ring against the shoulder just behind the square seal. The round o-ring will seal against the lip of the test tube.

Place spheres in tube and slide glass tube onto the cylinder with the mouth against the o-ring.

DO NOT FORCE TUBE

Slide the pivot ring over the end of the glass tube and engage threads with the threads on the cylinder. The pivot ring will draw the tube onto the cylinder.

Tighten the pivot ring finger tight. Overtightening may crack the glass tube.

Apply a light dusting of graphite to the cylinder. Be careful, graphite comes out of the tube quickly.

Slide the piston into the cylinder.

Tip the cylinder vertical, tube up, and work the piston back and forth to work in the graphite.

The piston should move easily, and you should feel the air pressure in the tube. The piston should be able to hang in the cylinder supported only by the vacuum in the tube. If the piston quickly drops out when released, or if it does not move smoothly, the engine will likely not run. Clearence between the piston and cylinder should be ~0.0008”

Place cotton wick in the far end of the burner tube. Twisting in the direction that tightens the fibers of the wick will ease installation.

Bend the end of the tube down so that it nearly touches the surface on which the engine sits. Also bend it slightly toward the front of the engine so that the wick will fall below the centerline of the glass tube.

Slide the connecting rod onto the crank pin on the flywheel.

Some versions of the engine may use a short pin that engages with only one side of the connecting rod tube. The short pin configuration is lower friction and less sensitive to pin straightness.

Next, bring the cylinder down into the base.

Position one of the set screws into the first pivot ring dimple.

Then rotate the cylinder assembly to catch the second set screw. Use 0.050” driver or hex key to adjust screws. DO NOT OVERTIGHTEN THE SET SCREWS

Overtightening the set screws will break the glass tube.

Gently tighten set screws into pivot ring dimples. Use 0.050” hex.

The engine runs best when the pivots have a tiny amount of end shake in the pivots. Once the engine is running well, a vibration thread sealant may be applied to keep the set screws from backing out. Do not use a thread locker (ie Loctite) and be sure to keep the pivots and dimples clean.

Spin the engine to check for tight spots or binding. If binding is noted, check that the connecting rod is free on the crank pin by gently shaking the connecting rod on the pin.

If the connecting rod is tight on the pin, investigate cause of binding. Burrs on the connecting rod, crooked crank pin, or misaligned pivot dimples are potential causes.

Light oil may be applied to the crank pin, but it is not necessary. Do not oil the cylinder, use graphite only.

Make sure the end of the burner tube is bend down so as not to strike the tube.

If the engine is turning smoothly, you are ready to run the engine.

Only run the engine in locations where candles or open flame are permitted and away from flammable materials.

Fill the burner tube with denatured alcohol using the pipette. Fill from the flared end. Never apply fuel to a hot wick.

It is not recommended to run the engine on oil base fuels.

Be careful, an alcohol flame is almost invisible in daylight.

Light the wick, allow the end of the tube to heat at least 30 seconds before attempting to start the engine. Once the tube is hot, gently push the flywheel to start the engine. Stirling engines are not self-starting.

If the engine is insufficiently warm, it may not respond or may get stuck. Excessive friction or too-tight pivot set screws may have the same effect.

Excessive heat may result in erratic running.

Extinguish the flame when finished.

If the engine runs out of fuel, the wick itself may burn as pictured. Avoid this condition.

Never add fuel to a hot wick. Blow it out and allow it to cool.

Be careful, the engine will be hot after running and will remain hot for some time. Do not touch the tube or burner end. Allow to cool fully before placing in storage.

Occasionally, one or more spheres may get stuck in the tube:

This is due to low spots in the glass tube, especially near the tip. Rotate the tube, or even the entire cylinder assembly, to remedy this problem.