Automotive Valve Grinding Tools

Written by lewis r. humphries
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Automotive Valve Grinding Tools
Valve grinding shapes the surface between an engine valve and seat. (engine image by KIERAN from

When automotive engine valves close, they seal against a seat. This seat is designed to set perfectly against the contour of the valve to ensure a complete and safe join. Over time, and through the application of excess heat within an engine, these valves fail to seal adequately, which means they need to be replaced or resurfaced. Valve grinding shapes the surface at the point of contact between the valve and the seat, ensuring that the valve can seal efficiently.

Motorised Valve Refacers

A motorised valve refacer is a hand-operated tool used as an alternative to the traditional valve grinding stone. This tool has various speed settings and is designed to ensure an accurate resurfacing of a valve face and seat. This tool requires no coolant or oil, and so is much cleaner to operate. It is most commonly utilised to resurface existing engine valves. This tool is manufactured with strong and durable tungsten carbide blades, which can be set at 30 or 45 degrees alternate angles.

Electric Valve Grinding Stone

The grinding stone is an electric tool used before the valve finishing process. This tool grinds the existing seat to match the suitable angle of the valve surface. The grinding stone uses a pilot to position itself and keep the valve centred during use. The pilot is a spherical piece of metal that slots into the valve guide to help maintain the optimum position. The grinding stone then comes into contact with the seat and is rotated, clearing all metal from the original seat and smoothing the surface. The valve seat needs to be checked regularly during the process to ensure that it is uniform and that too much matter has not bee removed.

Automotive Valve Grinding Tools
A grinding stone smooths the valve seat to match the correct angle of the valve surface. (old grinding wheel image by Jim Mills from

Valve Seat Finishing Device

A valve seat finishing device is used at the end of the valve replacement and grinding process. This tool is a precise piece of equipment that is designed to grind the surface at the join of the valve and seat to exact measurements, ensuring the most suitable fit and tightest possible seal. This is necessary to optimise the performance and durability of the valve and to prevent overheating within the engine. After this process, an abrasive or grinding compound is added to the face of the valve to test the contact point and connection.

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