This Weekend

This weekend I fixed the timing problem and it’s 100% better than it was. In search of lower temperatures at high speed I also changed to 5W20 oil; unlike watercooled engines that regulate their temperature directly with a thermostat, the VW aircooled engines primarily regulate their temperature indirectly via oil pressure. When the oil is cold it’s slightly thicker, causing the oil to compress a spring loaded valve and bypass the oil cooler; once it heats up it becomes thinner, allowing it to flow through the oil cooler in the fan shroud. In this way, the oil temperature is kept under control. However, if the oil pressure is too high even when hot, the oil will still bypass the cooler. In my case the oil pressure is high due to tight bearing clearances from the new bearings, and high RPM. It may get better as the engine breaks in, but for now I’ll just keep it at 55MPH or less except short bursts; the real solution here is getting the RPMs down with different transmission ratios. I also made good progress toward wetsanding and polishing, and got vinyl on order for all interior panels and seats.

 

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