BJ8 Water Pump Flow - point of reference

[Lotuswins]

Hi all,

So I finally was able to test the stock water pump for flow a couple of weeks ago, using a cheap flow meter off the internet, shaving it down to fit in the top water hose, and utilizing my Fluke 115 multimeter on the Hertz scale. This is just for a point of reference for anyone interested in these details. I have attached a picture of the flow meter being tested, and a pdf of an Excel spreadsheet graphing the results. I think it was tougher getting the excel pdf down to the 48.8k file size than doing the test:fat:. Anyways, I did all this since I've upgraded the fan and the radiator but still not entirely happy with the idle temperature when there is no breeze.

The results were a surprise! The pump was much better than anticipated, flowing around 10 gpm at idle, and 20 gpm at 2000 rpm which, from my research, is a pretty healthy flow rate. So now I guess I'll focus on reinstalling baffles and testing the air temperature into the radiator with a new thermocouple I purchased for the multimeter.

 

[bluegrass john]

I wanted to know if you were using an OE pump that has been rebuilt or an aftermarket pump that would most likely be a pump made by COUNTY; Please let us know.

Thanks for your efforts concerning pump flow.

John

 

[RAC68]

Nice work. You indicated that you gutted the thermostat. Was the bypass passage blocked or left open. If left open, flow rates may be misleading.

Ray (64BJ8P1)

 

[Lotuswins]

Ray & John,

The pump is a rebuilt original pump, so the impeller is the right size (the repop impeller I had originally had a discharge area significantly smaller than the original).
The bypass passage is blocked off with the gasket, so it is the true pump output. Thanks for mentioning, that is an important fact.