Quote:
Originally Posted by Ziggster
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Re: About oil pressure relief springs- Again
In the science of hydraulics, pressure will be constant throughout any closed system.....regardless of the distance from the pressure generating source (i.e. the oil pump). If there is a pressure relief opening (controlled by a spring loaded valve) the excess pressure will bleed off through this valve. Since the pump is capable of building more than enough pressure, the relief valve will be constantly bleeding off this pressure as long as the pump is running.
If you have two pressure relief valves, but they have different spring loads, the oil pressure will push against both simultaneously. What will happen is that the oil will bleed off through the lower rated pressure relief valve. The higher loaded spring in the other valve will continue to hold itself closed. So even if you have two or more relief valves, the system will seek its relief through the lowest spring load.....always.
As for our old flathead oil pumps, all the original Ford pumps (1932-47/48) did NOT have a built in pressure relief valve as part of the pump itself. Ford designed the system with a separate relief valve, engineered in the oil gallery line....the tube running from rear to the front in the valve chest. The early V8's had a 50 psi relief spring in there. Beginning in 1941 they changed the spring rating to 80 psi and it received a new part number. At the same time, Ford also changed the oil pressure sender unit to the 80 psi rated unit to match up to the new system rating.
Unless your older (32-48) oil pump is still in good operating condition, you would have to replace them with the latest version pump, which was the 8BA type. You can't buy those older pumps or kits for them anymore. The new style pump has one additional feature....it has its own built-in 80 psi relief valve.
So when you use this pump in the older motors with the separate relief valve up front, you can either remove the spring and plunger from this location, and put the hex plug back in place, or simply leave it all intact. I would change out the spring to the 80 psi type to match up to the 80 psi type in the oil pump.....if your sender unit and gauge are the 80 psi rating. Otherwise I would use the 50 psi spring.
We have both springs in stock. For some reason they are not listed on our website. I will fix that later today.
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VANPELT SALES LLC
Cincinnati, Ohio
Office: 513-724-9486
www.vanpeltsales.com
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