Tag Archives: cylinder
Vintage VW Parts Are Not Always the Best Parts
If you have experienced the magic of maintaining a Vintage VW engine you are familiar with the easy engine removal, the very convenient to work with engine size, the fast disassembly, and easy reassembly potential. Trying to use Vintage VW parts in a couple of areas can prove to be problematic.
One of the most common causes of engine failure, in the stock VW Beetle, and Karmman Ghia, is exhaust valve stem crystallization of the metal. The valve head frequently sheared into the combustion chamber. This Phenomena occurred historically, most often in Cylinder 3.
The strength and elegance of the older VW engine is that it is air cooled. The blower sits on top of the engine and directs the flow of air through the oil cooler and onto cylinder 3. Apparently the heat in number 3 is sufficient to cause exhaust valve failure over time as the brass valve guides wear.
In the air cooled engine valves are cooled by contact with the valve seat, and contact with the valve guide. The Valve stem is polished, hardened steel, and the guide is brass. As the brass guide wears exhausting gas follows the valve stem into the guide further degrading the brass, and increasing the gap between the moving valve stem and the guide. The net result over time, particularly with the Vintage VW part cylinder 3, is breaking off the exhaust valve head, which enters the combustion chamber, and punches a hole through the piston. Incredibly, the VW engine can still run after this event, noisily at first, then quieter after the valve head finds its way into the crankcase. Obviously the engine will not run well, and the metal shards will eventually damage the crank case components.
It is common to see this type of failure as early as 60,000 miles. Failure is not 100% but likely enough to erode reliability confidence. If you are operating a high mileage VW engine, or rebuilding a Vintage VW engine, it is advisable to review options for replacing stock engine heads with custom heads, modified to remedy the weakness of the vintage VW parts.
Several re-manufacturers offer some very capable options to vintage VW parts. It is important to research all of your options as you make buying decisions for rebuilding or maintaining your older VW engines.