High Pressure Water Pumps

sanborn

sanborn

Senior Member
I am building a flathead for my 40 PU. I want to use an aluminum radiator and be able to use 14 lb. radiator caps. I see Skip and Drake both offer newer style pumps with higher pressure seals. Will they operate sucessfully at high pressure OR do I need to go the GM water pump route?
 
As you may know using such a high pressure cap will put considerably more psi on your radiator and your rubber hoses. More likely to leak. Go with a 7 psi or 10 psi cap.
 
sanborn said:
I am building a flathead for my 40 PU. I want to use an aluminum radiator and be able to use 14 lb. radiator caps. I see Skip and Drake both offer newer style pumps with higher pressure seals. Will they operate sucessfully at high pressure OR do I need to go the GM water pump route?
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To answer your question, Drake's pumps will stand 14 lb's of pressure.
 
Yea i agree why such a high pressure. You will surly have troubles with this kind of pressure.{not needed] ken ct.
 
Pressure is not from the water pumps, pressure comes from elevated heat at about 210 degrees. The hotter it gets the higher the pressure. The volume of water pushed through the radiator and the amount of cooling surface of the radiator and air flow through or across the radiator surface is what cools the engine. Increasing any of the above helps and combining all solves the problem. Skips pumps are the only true high volume pumps that provide almost double the amount of water through the system. The rest of the pumps are not much better than the stock pumps. You only need a 4lb cap or 7lb at the most. The pressure cap serves the purpose of keeping the coolant from going out the over flow and allowing the coolant to be forced through the system. The restrictive nature of the radiator tubes requires the coolant be forced through the tubes. The pressure caps other function is a safety valve to release the pressure to keep the system from blowing up if the pressure gets to high. G.M.
 
sanborn said:
I am building a flathead for my 40 PU. I want to use an aluminum radiator and be able to use 14 lb. radiator caps. I see Skip and Drake both offer newer style pumps with higher pressure seals. Will they operate sucessfully at high pressure OR do I need to go the GM water pump route?
Click to expand...
Why don't you ask 'Skip and Drake':confused:
If they say "yes", and anything else fails due to over pressure it's on you.
 
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The boiling point of the water will raise 3 deg. frht. for every pound of pressure the cap is rated for. A 10lb. cap will raise the boiling temp to 242deg. frht. A 14 # cap will raise boiling point to 254 degrees F. And, as the pressure increases you will be able to see your top tank expand and possibly spring a leak. Remember, even though the water may not boil with these caps, the engine and its components and the OIL are getting very hot.
 
I tried a 10 lb. cap on my radiator once. It wasn't the water pumps that blew. It was the hoses and hose clamps that couldn't hold the pressure.
I'd concentrate on figuring out how to keep the engine cooler, not making it able to get hotter than he!! before it blows. :cool:
 
Older radiatiors were not built to hold higher pressures. Once they started building better radiators,they would hold the 14# caps with no problems. Pressure rises boiling point. Hoses and clamps will hold the added pressure if put on right.
 
To answer your question yes you can use a 14 pound cap with the new pumps made by Drake or Speedway. Dont know about Skips, they are rebuilt. You are also using a new alu. rad. The old rads wont take the pressure.
 
Old Henry said:
I tried a 10 lb. cap on my radiator once. It wasn't the water pumps that blew. It was the hoses and hose clamps that couldn't hold the pressure.
I'd concentrate on figuring out how to keep the engine cooler, not making it able to get hotter than he!! before it blows. :cool:
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Just a suggestion for future use and applications, assuming you are using clamps with a perforated screw-thread pattern instead of one that's pressed into the clamping band.

The sharp edges of the perforations dig into the hose and concentrate the clamping force in the area of the perforations rather than throughout the entire clamp. The pressed-in screw-thread pattern, in contrast, does not dig into the hose and permits the clamp to more evenly distribute clamping force all the way around the circumference of the hose.

These clamps also have rolled edges which are kinder to hoses. Mercedes-Benz has been using these clamps for decades, and you can probably harvest them from an import wrecking yard but you can also find them at auto-parts stores that support independent M-B service shops. Pricing is reasonable, and you can use and reuse them again and again.

I've been using these clamps for several decades after being introduced to them by my B-in-L who has a successful, long-time independent M-B repair service. I snagged the images from a technicians' service-tip site, posted by a fellow named Dave Coleman. BTW, the clamps shown were harvested from an old Merc and cleaned up to serve again!

Mike

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One other consideration. . . . if you use a 14# cap and you have a cooling system full of water at, nominally, 250*F, a blown hose will de-pressurize the system. Now you have water at 250* exposed to atmospheric pressure only. The superheated (above 212*F) water could/will flash to steam with pretty dire results. I would suggest there could be a significant safety issue here. Be careful.
 
On street machines 4 lb. should be plenty.
As Mike says, those serrated clamps are probably the best you can get.
Most street machines just use hose for the piping but on race cars we use all
metal. The joints have a gap of no more than 1/16 in. and the short hose section that connects them is special high pressure stuff and has 4 clamps on each connection with beads on the ends of the pipe. The track officials really don't like cars pukeing water on the track.
 
I appreciate all the responses. I really wasn't looking forward to the machine work to mount the GM type pump. I have enough machine work to complete the engine as it is now. Thanks!
 
With all the flathead Fords running on the road today, it would be utterly foolish to change to a GM pump.
 
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