Packard Forum Index » Post-War (1946-54)

Thanks Bilzpack, I also think this is the best and most simple. I'm working on the hole size difference question.
Thanks,
Larry

The answer to the hole sizes being bigger up front in the tube is velocity and flow rate. You have a ton of volume up front by the water pump so the holes can be bigger to get a certain amount of flow. As the coolant moves down the tube, much is lost and the volume of coolant at the end of the tube is less.

If the holes were as big as the front, then the water would move more "lazily" out of the holes in the back. By making the holes smaller, you're building up pressure with the remaining fluid and the new fluid coming in from the pump, and making it go through the holes faster. It's also that pressure that's built up that makes the fluid going through the bigger front holes move instead of dribbling. Think of it as a system pressure regulation setup, taking front water pump pressure and equalizing it throughout the tube so all cylinders get the same amount of cooling.

You can see this in large buildings and open floor plan restaurants when you see a large heating duct/tube get smaller and smaller in stages as it goes along, while using the same size holes in it to let air out. The only difference is the water dist tube uses smaller holes instead of the tube itself getting smaller.