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Scratch-building a 4-cylinder McVicker engine in 1/16 - Part 1


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In the November 2014 issue of Model Cars magazine my article on building a John Deere All-Wheel-Drive Tractor circa 1918 appeared. Since publication limitations prevail, the article spanned only 6 pages. Realistic, I know: who wants to read a lengthy article about a farm tractor in a model car magazine? (grin)

Still, there might be some merit in this tutorial on scratch-building the engine which powered this tractor since making an automotive engine - regardless of application - is modeling. Hopefully there is something useful in this tutorial to make it's use of bandwidth redeeming. :)

The engine in question was a lumpy 4-cylinder engine of 12 horsepower at the rear drawbar and 24 at the left-side pulley. This pulley drove various implements and farm machinery via a lengthy belt, and produced more hp since there were no drive losses. Aside from the many photographs I have of the 1:1 engine I also have a period brochure which provides some additional answers to questions I had as well as some flavor and ambiance of the times. The actual engine was manufactured by the McVicker Engineering Company in Minneapolis and the completed engines were shipped to John Deere in Moline, Illinois, for installation in the tractors.

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Page 1 of 4 of the original brochure.

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Page 2 of 4 of the original brochure.

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Page 3 of 4 of the original brochure.

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Page 4 of 4 of the original brochure.

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Left: a rough rectangular block laminated up from five sections of .120" sheet styrene. Center: the crankcase section of the engine with hand hole plates held shut by a clamp. Right: the Lion Roar photoetch frets from which the plate part numbers TM 208 were obtained.

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The four cylinders cut from brass tubing are in place on their base plate, along with bolt pads and Tichy Train Group (model railroad stuff) styrene hardware. Angled fillets made from strip styrene enclose the throw of the connecting rods. These are visible on the right side of the engine only. The left side is covered by a water jacket, part of the cooling system.

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A Dremel in the drill press with a cutting bit to mill out a portion of the engine block by hand. A speed controller (or rheostat) is essential to avoid melting the styrene. Watch your fingers!

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Scale Scenics Microfine solder which was used for the cylinder head gasket by lightly pushing it into the groove cut in around the block. This defines the separation of the cylinder head from the engine block.

Edited by BSteinIPMS
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The details added to the engine block and cylinder head show up nicely here. Nuts, bolts, spark plugs, and other items were fashioned from styrene strip and rod, along with brass rod and tubing. The engine is becoming more fun as details are added.

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The .125" styrene rod being softened over a candle flame in order to make nice sharp bends. Hold the rod well above the flame, say, three inches to start, and work closer to the flame as needed. Better to be conservative and allow the plastic to warm up gradually to maintain its (unmelted) shape which allows for more precise control of the radius of the bends.

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The exhaust manifold and pipes were fabricated from Evergreen .125" styrene rod bent to shape very carefully over a candle. The four sections of pipe were cut and added as two pieces that were attached with CA glue. These were sanded to shape when dry. Brass pins locate the manifold exactly in place on the side of the engine block.

Edited by BSteinIPMS
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The engine is becoming more detailed with the addition of the exhaust and intake manifolds and the gear case on the front of the engine. The brass tubing shaft protruding from the front of the engine fan gear case will have the fan mounted on it later. The part numbers TM 211LH and TM 210RH were added to the right-hand valve chamber covers, just under the intake manifold.

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A view of the engine gear case. Only the top half of the crankshaft gear housing is seen at the 6:00 o'clock position here. The lower half has already been mounted under the tractor frame and the two halves will mate when the engine is installed, appearing as an integral unit.

Edited by BSteinIPMS
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The pieces for the fan are laid out and centered on a cruciform shape marked in pencil on paper. The fan arms are glued to the hub plate with CA glue. The blades are curved and CA-glued to the arms, then rivets cut from .020" styrene rod are added using liquid cement.

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The finished fan mounted on the fan gear case of the engine using two sizes of brass tubing: one for the fan shaft which slides into the other - and larger - section of brass tubing in the gear case. This allows the fan to spin and also to be removed for painting separately.

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A rear view of the fan showing the curvature of the blades and the pitch they have as a result of the fan blade arms being twisted 45 degrees. Notice the spring on the shaft which was on the full-size engine. This spring was made by winding wire around the shaft.

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The details of the engine's left side include the water pump, magneto, and carburetor.

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The left side of the engine showing the mechanical lubricator at the lower right in this view. Above the lubricator sits an inlet air filter with a clear dust bowl on its bottom and a metal hose connecting it to the carburetor.

Edited by BSteinIPMS
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The right side of the engine showing the vacuum-driven fuel pump attached to the bulkhead on the left, the oil can on the frame in the center, and the oil can holder just to the right of the can. The stabilizing rods can be seen running from the bulkhead to the bolt on the engine water outlet fitting, and then forward to the radiator.

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A right side view with the hood open, exposing the engine. Hood prop rods will be made later.

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A left side view with the hood open exposing the engine and its accessories. It almost seems a shame to paint the model. Almost.

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Applying MIG Productions Dark Wash around engine details with a 5-O brush to create depth and shadow. This makes details "pop out" which is a subtle yet effective technique to make all the details more visible and realistic.

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The use of Micro-Mark's Doc O'Brien's Weathering Powders. The engine exhaust pipe is having Faded Blue pastel applied with a brush to indicate some minor heat discoloration. Rusty Brown and Grungy Gray will give a hint of rust and dust, although the total effect remains very subtle.

Edited by BSteinIPMS
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Detail Master .012" gray Ignition Wire is being used to add the spark plug wires running to the magneto. Detail Master makes a wide variety of wire in various diameters and colors.

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The hoses for the engine's cooling system were made up from insulation cut from electrical wire. The copper wire strands were removed, leaving just the hollow hose. Photoetch stainless steel hose clamps from Detail Master completed the realistic look of the hoses.

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The open hood reveals the McVicker 4-cylinder engine of 24 hp. The two access plates on the crankcase are held in place by a clamp. On the rear bulkhead is the vacuum-driven fuel pump, a large accessory. Four lubrication lines emerge from the cooling jacket which carry oil to the pistons. These lines originate at the mechanical lubricator positioned on the engine's left.

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The forward side of the engine bay contains the fan, fan shroud, and an oil can held in its three-fingered mount. The upper radiator hose running to the water inlet fitting on the engine is evident. The operating hood latches may be seen, along with their hook-shaped retainers.

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The open left engine bay reveals the four spark plugs at the top of the engine, the spark plug wires running through a conduit, the exhaust manifold, the intake manifold, the carburetor with the segmented steel hose leading to the air cleaner with its sediment bowl, and the mechanical lubricator in its brass housing.

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The forward section of the engine bay shows the brass magneto mounted on a bracket on the engine and the magneto drive coupling running forward to the gearbox. Below is the water pump with its coupling and green grease cup. The eight oil lines emanating from the mechanical lubricator were made from copper strands pulled from electrical wire.

Well, this concludes this tutorial, and I hope you found something useful in all this even if it is a lowly farm tractor. :D

Cheers!

--Bob

Edited by BSteinIPMS
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Bravo Bob, you are a true master - your attention to every tiny detail, brings this model to another level. The memory of this post, will serve me in the future; perhaps when I am having issues with scratch building a part ........ and definitely, when I read about a slug having a hard time putting together a "Groovy Grader" :blink::D

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any chance you could share a good way to make spark plugs? and attach wires without boots? like the old Rajah screw terminals.

thanks

Hi Joe,

Glad to. The way I made these spark plugs was this:

1. Cut sections from Plastruct hexagonal styrene rod for the bases of the plugs. (This product comes in several sizes.)

2. Chuck a section of the appropriate size styrene rod in your Dremel and turn the ceramic portion of the spark plug using files.

3. Drill a hole down in the top of this rod and insert a short length of brass rod which becomes the terminal fitting.

4. Using Detail Master wire of the appropriate diameter for your model, strip a bit of insulation from the end and wrap this around the brass rod to make the connection.

5. Paint as desired.

Cheers!

--Bob

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Ok Holy Cow, you can make a tractor look like a supermodel!

I like that you are doing the accent/weathering style painting to your engines to up the realism

It is the airplane, figure and tank guys who do all the washes and such to weather their builds. That is where I have learned a little bit

of what you are doing....still long way for me to go

Again great work!

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