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Part 9: Water Pump
There were very few street rod parts made for hemis up into the 90's in general and zero for the early 331 hemi. As you might guess, the engine compartment of a Willys is small enough without installing one of the physically largest engines ever made, so room is at a premium. The 331 came with a cast iron timing chain cover and has the water pump cast onto it, making the stack fairly long. This gave me a problem with fitting the radiator under the stock hood so I decided to cut the pump off the chain cover and mount one separately. Remember, no aftermarket available in 1980. I stumbled on what I think is a nifty solution. If the discussion it gets at rod runs by spectators is any indicator, other people agree.

I found a small horsepower centrifugal pump in the company junk pile. It had a stainless steel body and pipe thread inlet and outlet ports. The close-coupled electric motor and belt drive photos below show how these pumps are found and they are very common in all sorts of industrial applications. The figures show that the mounting plate they come with isn't useable on a car so I had to make my own.


(Click photos to enlarge)


The photo below is a copy of the drawing I made for a new stainless steel shaft and aluminum front plate. Compactness was the primary specification. I used the shaft bearings from the original Chrysler pump, and the water seal is a standard industrial item. The pulley hub is a Chrysler item too.


(Click photo to enlarge)


The photo below shows the pump completely assembled. The pulley came from some junkyard car, I think from a smog air pump. You can see the copper pipe fitting I used for the outlet. I soldered together a little copper pipe manifold that bolted to the block and connected it to the pump fitting with a short piece of hose. All the copper parts were chrome plated.


(Click photo to enlarge)


The pump inlet pipe is shown in the two photos below (raw and finished) and is a little involved. It had to take water from the bottom of the radiator and screw into the inlet on the rear of the pump. I made it out of a piece of curved water pipe I had in my junk bin. A lot of welding and custom brazing to get the screw fitting on the top, then off to the chrome shop. The pump mounts with a bracket on the front that bolts to the block, head, and 3 pump bolts.


(Click photos to enlarge)


There is a lug on the water inlet pipe that bolts to the intake manifold for a sturdy 3-point mount, as shown in the photo below.


(Click photo to enlarge)


I started out using the 3 vane impeller that came with the pump but it was too efficient and moved way too much water (see chart below). It would foam the fluid and it would boil out of my radiator on a hot day! I got a junk yard impeller from a Chevy water pump, brazed it to the proper stainless nut and it works great since it is less efficient. Diameters and thickness of my pump and a V8 pump are the same.


(Click photo to enlarge)

To see my '53 Chevy Pickup Truck Project Journal, click here.


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