Honing a cylinder sounds complicated at first, leading many people to take their engine blocks to professionals for a simple hone. In reality, honing is basically just polishing metal, and it is something the average do-it-yourself mechanic can easily do once the engine is stripped apart. The tools required for this project are inexpensive and can easily be found over the Internet or at many automotive stores. A cylinder-honing kit usually attaches to an electric drill and is a simple cylindrical device with an abrasive surface. The spinning device is thrust into the cylinders multiple times until the desired surface texture is achieved. These instructions assume you have already torn the engine down, the cylinders are exposed and you are ready to begin honing.
Select the proper-sized honing tool. Keep in mind when making your selection that these are intentionally built slightly oversized. For example, if the cylinder you want to hone is 2 inches wide, there is no need to purchase a honing tool that is larger than 2 inches wide. It will automatically come slightly larger so it applies adequate pressure to polish the cylinder walls. The amount of polishing done is not determined by the width of the tool, but rather by how long it is used inside the cylinder.
The desired rotational speed is 1,200 to 1,600rpm, so make sure that speed is within your drill's normal operating range at full power. If your drill has a speed selection switch, set it to around 1,400rpm. Any rotating device that operates within the required rpm range will work, but a drill is usually the most convenient device for this task. If you're using a cordless drill, make sure the battery is fully charged before beginning. A reduced charge could lower the rotational speed and alter the results.
Apply lubricant liberally to the honing device. Any oil-based lubricant will work for this task. Mineral oil or a lubricant specifically made for cylinder honing will work fine. Slowly rotate the honing tool using the drill, and pour oil over the entire contact surface. To ensure proper lubrication, apply more oil than what appears to be necessary. It is better to have too much than not enough.
Hold the trigger on the drill to maximum operating speed, and quickly thrust it in and out of the cylinder several times. This process removes metal rapidly, so don't go more than five thrusts without stopping to check the cylinder walls. The desired finished product will be shiny, without visible nicks, scratches or wear, but you want to remove as little metal as possible. When it appears you are halfway done, reverse the direction of the drill (clockwise instead of counterclockwise, or vice versa) to produce a criss-cross pattern that helps oil stick to the cylinder walls.
When finished, wash the surface area with soapy water. The honing process produces metal dust and fragments in the cylinder that could potentially cause engine damage, so it is important to clean away as much of the metal as possible. When the cylinder has been thoroughly washed and dried with a lint-free cloth, apply a thin layer of motor oil to the freshly polished surface to prevent oxidation.
- Once you are finished with the honing kit, it is not likely you will use it again in the near future, so consider selling it to recoup your money.
- Check your progress often to avoid removing more material than needed.
- Always wear safety glasses when working with power tools.