I ordered a set of water pumps for my 53 8BA engine from LMC Truck, P/N 43-2642. My original two pumps are essentially mirror images of each other except for the heater hose port on the right side.

The new pumps appear the same left to right except for the impellers and gaskets. The biggest difference between the impellers is that the one on the right pump has 2 holes drilled from the exposed face to the root diameter between vanes. The impeller on the left pump, like the impellers on my original pumps, has no holes. The other difference is that the impeller on the left is machined 1/32” smaller than the right impeller, and as such the machining on the larger left one does not clean up the tips of all of the vanes.

The gaskets with the new pumps are very different from one another, as can be seen in the pictures. In the left pump, the water passage at the top of the pump is open to the impeller cavity. The right pump gasket closes off this hole. What path would the water take?

Ordered 43-2642 for 53 F100

Original Water Pumps

New Water Pumps

Water umps with differing gaskets

Impeller Holes on Right Pump

Solid portion of Right Gasket.


Basic questions: 1) Has anyone seen a pump with holes drilled in the impeller? 2) Does the water exit the pump and enter the block through the hole at the top opposite the pulley? 3) Are the left and right water jackets within the block completely separate until they enter the radiator? 4) Why would the left and right gaskets be so different? 5) Would the restrictive gasket shown on the right pump prevent the water from entering the water jacket? Thanks for any help you can offer.

 

Art, First, don't worry about the holes in the impeller. I don't know what they are for but it shouldn't be an issue. The difference in impeller diameter, I would make sure that the larger fits and spins freely in the block. If it does, no problem. The gaskets being different, well that goes along with the diff in the impellers, I'm thinking probably two different manufacturers. It doesn't matter either way. Water enters the pump through the radiator hose, goes THROUGH the pump, and enters the engine through the hole where the impeller goes. Upside down and backward, yes.
And yes, the block is split into two separate cooling systems sharing a common radiator, hence two water pumps, two upper, two lower hoses, and two thermostats. I always recommend adding a coolant recovery system on flatties. It keeps the coolant in the system instead of on the road, minimizing your chance of air pockets and localized hotspots. You will need a pressure cap to go with, 2-3 psi is sufficient. HTHY

 

Thanks for the information. I bought new gaskets that fit the pump faces and installed the pumps. They seem to be working OK.

 

Cool beans