Cylinder heads

Cylinder head rebuilding is one of the basic stages in the repair of the entire engine, since cylinder heads are the mechanical driving force of internal-combustion engines. We use innovative welding technologies, machining and many other processes, thanks to which rebuilding can be carried out in a reliable manner, even in the most complex of cases. To ensure the quality of cylinder head rebuilding we use a machine from an American company, Sunnen, which is part of our machine facilities. We are able to repair all types and sizes of cylinder heads. Successful rebuilding of cylinder heads is a crucial part of the engine rebuild process, which cannot work properly and efficiently when the heads are not in good technical condition.

Cylinder heads are usually made from cast iron or aluminium. They are fitted to the upper part of a petrol or diesel engine. They are used for the combustion of a fuel mixture. Without them, the cylinder liners of the block would be open, so the combustion process would be impossible. Cylinder heads contain oil and cooling passages, as well as special sensors for oil pressure and coolant temperature.

These parts have one more important function: ensuring continuous lubrication of the cylinders. Without proper and continuous lubrication, a petrol or diesel engine could not run smoothly. Cylinder heads also ensure that the engine has the required stiffness, ensuring that it is durable and its operation does not generate excessive noise.

The level of wear and the extent of any damage largely determines which elements are subject to repair or replacement during the rebuilding process. Most common failures occur to the valve seats, valve guides and the head surface due to cracking, as well as the camshaft bearings. Depending on the scale of damage, we take optimal measures during the rebuilding process to restore the cylinder heads to full operating and technical condition, in accordance with the manufacturing parameters. Repairs might be required, such as milling or even replacement of valve seats, rebuilding or replacement of valves, replacement of valve guides, repair of threads, verification of the camshaft bearing condition, or restoration and grinding of a cracked head surface.

Proper rebuilding of a cylinder head is extremely important as it determines the correct operation of the engine and its wear and tear, among other things. The engine must be disassembled for cylinder head rebuilding. This can be complicated and therefore requires appropriate knowledge, experience and qualifications. For this reason, you should not do it yourself. When done incorrectly, the repair is not only a costly mistake, but also an unnecessary waste of time. So, it is a good idea to delegate the head rebuilding process to specialised service providers. Below we present the stages of cylinder head rebuilding that we carry out.

We disassemble the head at a special station used for both the removal and safe installation of cylinder heads. We start the head rebuilding by checking the sealing using a special tool that allows us to perform this operation under temperature conditions similar to the temperature of the working engine. At this point, we can thoroughly analyse the damage and detect the fault location.

After locating the leak, the head is prepared for the welding process and then for preliminary machining. After this is complete, the head is again subjected to a sealing test. Thanks to this, we can be sure that the detected leaks have been removed.

After successfully passing the sealing test, we proceed to replace the valve seats and valve guides. We use a reliable valve guide rebuilding technology, which consists in upsetting the inner diameter of the worn-out guide with a special tool, followed by honing with a diamond tool. 

Next the camshaft bearing in the head is verified, and, if necessary, the head is machined on a specialised machine tool. The valves used in the restored head are also verified. After verifying the wear of the caps, the valve disks are ground on a grinder.

The final machining of the head involves planing of the head surface and machining of the valve seats, which we carry out using a profiled milling machine. After individual matching of each valve in the head, the sealing of the valves is verified using a pressure tester. The final stage of cylinder head rebuilding is correct installation. This includes assembly and adjustment of the heads.