Valves

How do I know if my engine valves are bad?

Identifying bad valves can involve several symptoms and diagnostic methods. One of the first indicators that there may be a problem with the valves is loss of power and a skipping, 'popping' sound in the exhaust pipe. You may also find that the engine has a rough idle, emits excessive exhaust smoke and uses more oil than normal. Each can indicate one or more valves has a problem that should be addressed. Each cylinder can be checked with a compression tester to know if the valves are leaking pressure, also a result of a defect valve, indicating that one or more valves should be inspected.

What is the difference between intake and exhaust valves?

Intake and exhaust valves serve different purposes in an internal combustion engine, which are crucial for optimal performance. Intake valves open to allow the air-fuel mixture to enter the combustion chamber. They close during the compression and combustion phases. Intake valves are located on the cylinder head’s intake side and are designed with a (most of the time) larger diameter to increase airflow into the combustion chamber. Exhaust valves open to let exhaust gases escape after the combustion process. They are made from materials that can endure higher temperatures and have a smaller diameter than the intake valves. Exhaust valves often incorporate a special alloy or surface coating due to the higher temperatures that they have to deal with.

Why do intake and exhaust valves need adjustment?

Engine valves are initially adjusted to ensure optimal performance, engine longevity, and fuel efficiency. Valves set too wide are noisy and result in poor engine running and less power. Valves set too narrow is much worse. This can cause the valves to not close completely. The leaking combustion gases cause the valve plate to increase in temperature so much that it will burn.

Valve adjustment is a precise job that maintains engine performance. It can be done with an adjusting bolt and locknut, but this is becoming less and less common. These days, valve clearance is adjusted by using custom tappets or tappets with valve levelling plates. Both methods are much more accurate and require little maintenance. Then, of course, there are the hydraulic tappets that require no further maintenance.

How much does it cost to replace engine valves?

The cost of replacing the valves is difficult to estimate as it falls under a cylinder head overhaul and can vary from application to application. It depends on several factors, such as the make and model of the vehicle, the type of engine and valves used. Wilmink Engine Parts offers valves from several A brands, such as Eaton, Kolbenschmidt and MAHLE. For the hard-to-find valves we have valves made under our private label. But we can also supply so-called 'blanks' by means of a special order. These are valves which you as a customer can further customize yourself.

We have our private label valves produced after a sample has undergone an extensive inspection. Inlet valves and outlet valves are not always made of the same material, and we always choose the material that is at least equal or even better than the original. A valve must withstand high temperatures and seal well on the valve seat. The valve must be able to rotate freely in the valve collet. We always recommend that when replacing the valves, we also replace the valve spring cotters.