How to Sand Cast an Engine Block

by Paul Jeter
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Sand casting an engine block takes time, preparation, materials and resources. Foundry experience and tools are necessary. You will be handling molten metal at temperatures above 1,000 degrees F. Pouring metal requires team effort. You'll need a friend to help to pour and one or two people to assist. Sand casting is quicker than using plaster, and it is used for engine blocks and other parts that do not need a refined surface. The sand is prepared and the metal is poured. Then, the engine blocks cools before it can be machined.

Step 1

Get everything ready for the pour. Arrange a time and date for your team to help. Ignite the furnace and drop your aluminum into the crucible.

Step 2

Make a mold of the engine to be cast. Spray the surface of your disassembled engine block with graphite spray. This will lubricate the surface and create a layer so the sand does not stick to the original piece.

Sift the sand. Add a splash of water so the sand is not completely dry. Press it into the wood box. Tap it down. Lift the engine block and press it into the sand. Pull it out again and set it aside. Clean off the engine with water. Fix any spots in the sand that did not come out completely. Flatten the top. Add air vents if necessary. Spray the sand with the graphite.

Step 3

Add enough aluminum to the crucible to fill it. You will need roughly 200 lbs. of aluminum depending on the model of your engine. Open the blast door carefully. Drop in each ingot using your foundry tools carefully. Skim off the "scum" on top using your foundry tools. This contains alloys and other metals that may make your engine block unstable.

Step 4

Begin the pour. Dress in the protective attire. Have a fire extinguisher ready. Team up with a friend for the pour. When you are ready, pull the crucible out of the furnace and walk over to the sand box. Pour the hot metal into the sand, making sure to fill all areas. When it has topped off, replace the crucible in the furnace.

Step 5

Break the mold after it has cooled one to two days. The cast should be room temperature before you try to handle it.

Step 6

Machine the engine and remove imperfections.

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