Smithsonian Model Engine Building Directions

Insert the piston pin into the top of the piston connecting rods. Attach a piston half-head to both sides of the pin, two in all. Repeat three more times to make the four pistons.

Mount one piston on the crankshaft on the flat section of the shaft. Keep it in place using a connecting rod keeper and a pair of screws. Repeat with the other three pistons. Flip the crankshaft upside down to test that it works. The pistons should dangle freely. If they don't, loosen the connectors.

Screw the oil pan to the bottom of the lower crankcase. There are four pins on the bottom of the crank case, which will fit into slots on the oil pan.

Insert the four pins on the bottom of the oil pan into the model stand.

Flip the cylinder block upside down, so the cylinders point downward and the two slots on the front and back are on top. Drop the four pistons into the four cylinders and place the crankshaft into the slots on the edge of the piece.

Flip the cylinder block over, holding the crankshaft in place. Place the block over the lower crankcase assembly and screw the two pieces together, using six screws, into the six holes along the side of the crankcase. Test spin the crankshaft to see if the pistons move properly.

Insert a valve piece into one of the spring pieces. Insert this unit into one small hole in the top of the lower cylinder head. Push down to compress the spring and clip the valve into place using the small exhaust valves. Repeat with the remaining three small holes.

Repeat the process of making a valve and spring using the larger holes and the larger exhaust valves.

Place the head gasket over the top of the engine block and put the cylinder head over the top of this. Screw the units into place using six screws.

Slide the rocker arms onto the round rocker shaft. The arms should alternate. If you put the first arm so it points left, the second should point right, and so on.

Position the rocker shaft over the upper cylinder head. Two rocker arms should fit into each of the gaps on the head. Separate the arms so that the pieces fit into gaps for the arm. Screw bearings into place over the rocker shaft to keep it in place.

Slide the cams onto the cam shaft in order. Each cam is labeled with a letter between "A" and "H." Slide these onto the grooves marked on the camshaft.

Point the camshaft so that the H end is nearest the grooved handle on the crankshaft and place the camshaft into the grooves at the top of the cylinder heads.

Screw the upper head onto the lower head. There are four screw holes on both pieces, and they will only line up in one direction. Make sure they line up and screw them down.

Place the rocker arm cover on top of the engine block and screw it into place.

Slide the timing gear onto the grooved end of the crankshaft at the bottom front of the engine. The gear will only fit on in one direction, so if it isn't sliding into place, it needs to be switched.

Push the camshaft from the back of the engine and hold it while you slide the upper timing wheel onto the other end of the camshaft.

Hold the alignment tool over the two gears you've installed. There should be three circles on the upper gear and one on the lower. Line up the three dots on the tool with the upper circles and point the small dot on the crankshaft gear away from the bottom of the tool. Attach the tool to the device.

Slide the timing belt over the two gears. Pull the belt toward the bend in the tool and slide the timing pulley onto the post between the two. Remove the alignment tool.

Slide the timing belt cover over the timing belt and screw it into place.

Attach the two halves of the water pump to each other, then slide this onto the front of the model so that the pump hose points toward the engine block. Screw the piece into place.

Attach the fan belt pulley to the shaft sticking out of the water pump and screw that into place. Next, screw the fan into place on the front of this pulley.

Screw the camshaft pulley onto the camshaft at the bottom.

Loop the fan belt around the fan and then pull it down and attach it to the camshaft pulley. Spin the fan to test that the model works.