Reassembling the Viking

Now that the Viking has been dismantled, cleaned, and painted it is time to put it back together. For me this step often takes the least time because I am by this time familiar with how the engine works and know how it should fit back together. It isn’t my favorite step towards restoring a motor: I am always worried that I’ll find out I am missing a part or two during reassembly! This happened to me once when I discovered that the float bowl for the Shrimp’s carburetor was missing. It’s made of glass so it would be extra hard to replace. I did find it, but I lost it because it wasn’t together with all the other pieces of the Shrimp which I kept in a box. I could have saved myself the trouble of searching by simply keeping this glass bowl in the same place as the other engine pieces.

Above: The float bowl.

I started with the lower leg. This means fitting the propeller axle and gears into the gear housing, fitting in the drive shaft, and then attaching the whole contraption to the block. Don’t forget the gear oil! This lubricates the gears and is very important. Also down by the gear box is the rotary water pump – it relies on seal and spins with the motion of the propeller axle. It’s kind of like an impeller, but not as reliable! The seal on this Viking was bust, and the pump wasn’t doing its job. Fortunately I had some help with a experienced engine enthusiast on this one.

Top: The rotary pump. The black circular piece directly around the silver circle is the rubber seal.

Next, I put the cams and piston back inside the block and I didn’t put the head on until last. To cap it off (quite literally) I screwed on the crankcase bearing assembly, which appears on the top of the block. It is kind of like a little hatch and makes it a lot easier to get the cams out.

Top: The partially disassembled block.In the center is the bearing assembly, you can see it where the black oil is in the middle.

Next I rebuilt the carburetor and bolted it onto the block. There isn’t a lot of space to move a wrench where the carburetor bolts on, as a result this step takes a long time.

Tools: Mainly, I used a socket set. This is comprised of three ratchets, and a multitude of different size bits. their purpose is to remove nuts and bolts. I also used a hammer to take off the flywheel. Usually to remove a flywheel you loosen the flywheel nut, and then hit it squarely with the hammer. This loosens it from the tapered end of the crankshaft.

Above: The Head

Now I am almost finished rebuilding the Viking, and I am just about to put the head on over the piston and screw it on. The combustion chamber has a tapered end so that I don’t need a ring compressor – all I have to do is slide the piston into the head. However, the piston has two rings for compression sealing. Each ring has a notch which help keep it from moving about, and the rings must be aligned with the notches or the piston won’t fit in the combustion chamber.

At this point I didn’t know the two notches for the piston rings were even there. Everything has gone smoothly so far… until I attempted to put the head over the piston. Of course, the piston rings weren’t aligned with the notches so the piston was not going to fit into the head. In the end, I broke one of the two rings. Now I had a problem! How was I going to get a new ring? It had to be a perfect fit on the piston, or it wouldn’t seal. In the next post this will be discussed.

Above: Broken piston ring.

I could have been a little more careful when putting this motor back together. A good idea is to examine the pieces of an engine carefully, check for small notches or anything else that might otherwise go unnoticed. Go so far as to use a magnifying glass! This can come in handy with tiny engines  such as those found on model airplanes (like the one below).


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