If you recently found and purchased a used engine block for your restoration project in a junkyard, you may have discovered a thin layer of rust on the exterior's surface. If so, use the following three-step guide to removing the rust using items you may already have at home or in your garage.
Step 1: Dab White Distilled Vinegar on the Rusted Areas
This first step involves treating the rusty areas with white distilled vinegar. The acetic acid in white vinegar softens the rust and loosens it so you can scrub it off of the metal more easily in the upcoming steps.
When applying the vinegar, only use it on the external surfaces of the block. Do not use it inside the cylinder walls, since any residue could eat away at the pistons you will be installing inside of them later on. To clean rust out of the cylinders, contact a used parts professional like U Pull & Pay to seek their advice.
After dabbing the vinegar on the outer surface of the block, let it sit for an hour or two so that the vinegar has time to work on the rust and dry. Then, go on to the next step.
Step 2: Use a Small Wire Brush to Scrub the Inside of Any Crevices
Once the vinegar has dried, this next step involves using a small wire brush to remove any rust in the crevices and crannies on the block. Once again, do not use this brush on the cylinder walls, as any uneven scratches in the metal could cause the pistons to move erratically.
Apply a small amount of pressure while scrubbing the rust. Then, wipe away the dust with a damp rag, letting the areas dry a few minutes before proceeding to the next step.
Step 3: Sand the Rust off with Medium-Grit Sandpaper
After you have removed the rust from the hard-to-reach areas, it is time to remove the rest of the surface rust. Use medium-grit sandpaper for this step, since it will dig into the rust without scratching into the metal.
Sand the rust until you see clean, bare metal. Then, wipe the block with a damp cloth, and let it air dry.
Using the above guide can help you remove a small amount of rust from the exterior of the used engine block. However, if you find thick areas of rust or any rust is coating the inside the cylinder walls, speak with a representative at a used auto parts store to get recommendations for products to safely remove the rust without damaging the block.