1934 eight radiator cap

Posted by Bill Hawley On 2022/7/15 18:35:21

I just pulled and inspected my water pump and flushed the radiator and engine block. Putting things back together I realized that I need to know more about the radiator cap itself. Not the figure on the top but what the cap looks like underneath. I have two caps and they both are different. The one I'm guessing is more correct is configured in the following way. If you turn the cap over and remove the central bolt, next comes the metal piece with the three stubs that fit into the slots in the top of the radiator. Next is a fiberous gasket, thin, almost like very firm paper. Finally there is a metal (brass ?) convex washer. It seems like the metal washer pushing the gasket onto the ring of the radiator opening forms the seal. But, inside the radiator opening is the top of an overflow tube that sits far enough below the gasket that nothing appears to seal it off. So my questions are:
1. What is the underside of the cap supposed to be configured like?
2. Is this a sealed system?