VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 38 Master Sport Heater Hoses?

Just curious in the pre-'48's non-pressurized cooling systems, just how much pressure their is?

None - it is vented to the atmosphere. So that means straight water will boil at 212 Deg.sea level. In 1947 the temp. gauge read 212 deg and and 1948 220 deg

I just purchased a 1938 Deluxe Harrison heater and will purchase the shutoff valve and black hoses. Mine does not have the shutoff valve

Can I simply remove the fitting and insert temp sensor directly into block? It looks like I can.

Yes, that's where it would normally go. Are you clear about the hose connections at the front of the engine?

Again, you do have a shut-off valve. Shaped like the one Tiny has on his '37. Just to be clear.

Russell,

You ask an interesting question about the pressure that the water pump can develop.

We know it does develop a pressure differential to overcome the resistance to flow in the block, head, hoses, and radiator.

Given the relatively simple design of the pump and the clearances between the impeller and housing it is not a vary efficient pump. It does run pretty fast when the car is going down the road.

A centrifugal pump is intended to move high volumes of water without increasing the pressure. On the other hand, at higher flow rates (higher engine speed) the resistance to that greater flow will create more pressure.

Maybe someone has a pump performance curve for this generation water pump. It would not surprise me if the pump could produce 15 to 20 psi at higher speeds.

This is from the 1938 Genuine Chevrolet Accessories

I just posted a picture of the correct shut off valve

I can buy the nos one or get a similar one from chevsofthe40s

Thank you for educating me, I had to catch up too your thinking and review the images. Everything makes sense now. Might be my imagination but seems awfully tight around the water pump and radiator fan unlike my old 38

there is a very nice 38 Master for sale on craigslist, los angeles but i think the car is in arizona. The heater hose is mounted to the shutoff valve closer to the firewall like my 38 Master. My old 38 Master Deluxe Town sedan ran the hose to the water pump.

That is the incorect location for the shut off and the hose.

All the solutions we discuss about heater hose routing, connections, and valve location will work. Hot coolant will get circulated to the heater core.

It becomes a different discussion and answer when someone wants to do it “correctly” for their particular vehicle.

I prefer the Master Deluxe routing, cleaner.