VW VALVE BREAKAGE
It is not uncommon for the Volkswagen 1.8L, 20-valve cylinder head to require several if not all new intake and exhaust valves once it reaches your shop door. A failed belt, water pump and tensioners can provide quick and devastating havoc inside the engine and some valves will always come in contact with the pistons. Improper assembly may also create havoc if the assembler is not cautious. In the accompanying photos you can see how the valve springs may be installed, but not seated correctly in the spring pocket. It can be difficult to catch and picture #2 shows how it may be observed through the cylinder head. Should the engine run for even a short time in this configuration, the resulting side load on the valve as it travels up and down the valve guide will cause the valve to flex and break at the weakest or narrowest point, within the valve keeper grooves. When this happens, the broken valve will fall free from the retainer and drop into the combustion chamber causing massive failure. Double and triple checking that the valve spring is properly seated may help save the shop from a very expensive warranty situation.
Engine Pro Technical Committee
February, 2021
