A Closer Look at a Valve Seat Cutting Machine

A Closer Look at a Valve Seat Cutting Machine

We recently welcomed a new addition to our workshop, a new valve seat machine (a Robins SG9), to ensure our valve seat reconditioning service is the best it could be. With valve seat cutting machines developing so much over the years in accuracy, speed and accessibility, we feel they are the best method for ensuring precision and efficiency during the valve seat reconditioning process. But, what is a valve seat exactly? And why are they so important? We discuss both of these questions, including the reasons why we believe a valve seat cutting machine is the best method for cutting valve seats, as opposed to hand cutters.


What is a valve seat?

A valve seat is the surface that an exhaust valve rests on when the valve is closed during the combustion process in a diesel engine. The valve seat, alongside the valves, helps to seal off the combustion chamber in the cylinder head and prevents the impact from the valve burying into the cylinder head by absorbing some of the heat from the valve.


When is valve seat replacement needed?

Replacing valve seats is often needed as a result of the cylinder head cracking or damage. To find out more information about how to spot the symptoms of cylinder head problems, head over to our blog post to help diagnose the key issues faced. The stress experienced by valves means when they are replaced, they need to be handled with care. It’s important to remember that just as much care needs to be taken with valve seat replacement, so the cylinder head isn’t damaged further.


What is valve seat reconditioning?

Rather than replacing the valve seats entirely, burnt or worn valve seats can be reconditioned and restored to normal working condition through cutting or grinding. The valve seat needs to be an exact size for its functionality, and often damaged valve seats need to be cut or ground to have a common centre with the valve guide that connects the valve seat to the valve.


Valve seat cutting machines vs hand cutters

A valve seat cutting machine is the most accurate and efficient tool for cutting valve seats. As the valve seat has different angles, hand cutters will struggle to achieve the precision needed to ensure each angle is accurately cut. This also rings true when it comes to the transition of the different degree cuts that are required; accuracy is needed to ensure each degree cut is correct and this cannot be achieved by hand cutters alone. A valve seat cutting machine can also accurately measure the concentricity of the valve seat surface using a gauge, providing complete accuracy so the valve seat and valve can have the contact needed for the engine to run safely and efficiently.


You may be wondering how versatile a valve seat cutting machine is, well that depends on the machine. Still, we know the Robins SG9 is well suited for newer multi-valve cylinder heads, as well as the older, more classic cylinder heads. This piece of equipment truly is essential for ensuring any valve seat reconditioning service delivers the best quality and accurate cutting it can.


Please contact us with your engine number if you are currently experiencing cylinder head problems or any diesel engine-related issues. Foxwood Diesel is a national distributor of Cummins spares and engine parts, as well as Mercedes, Volvo, Perkins, DAF and all major diesel vehicle manufactures, with a wide range available for same-day dispatch. We have a dedicated team with over 70 years of experience between us, able to undertake highly effective reconditioning and rebuilding solutions, so please don’t hesitate to get in touch should you require our services.