Insight
Micrometric Tolerances, Guaranteed Performance: The Precision of PIMAX Valves
Key components in the operation of four-stroke engines, engine valves control the sequence of intake, compression, combustion, and exhaust phases. Located within the cylinder head and sealing the combustion chamber, valves move up and down under the control of the camshaft, whose rotation is in turn driven by the crankshaft. This motion opens and closes the intake and exhaust ports in the cylinder head, ensuring proper engine functionality.
As critical elements of the valve train system, engine valves are subjected to continuous mechanical stress and extreme thermal loads—particularly exhaust valves, exposed to gases that can reach temperatures of up to 900°C.
Modern engines are multi-valve designs, featuring a variable number of valves per cylinder (up to five). This improves engine performance but increases maintenance complexity, especially when replacing worn components—operations often carried out in specialised engine reconditioning workshops.
Cleaning, Maintenance, and Replacement of Engine Valves
If vehicle performance drops and the engine feels sluggish, or if noise increases—especially at higher RPMs—there may be an issue with intake or exhaust valves. For DIY inspection, the following steps are recommended:
- Visual inspection of all valve components, including stem and head (or valve face)
- Cleaning and measurement of valve head thickness using a precision caliper
- Checking the condition of the valve seat (guides) and springs (single or dual springs, symmetrical or asymmetrical pitch)
If no critical defects are found that require replacement, valve lapping can be performed to restore optimal sealing performance.