Flathead water pumps

[RKS.PA]

When I rebuilt my '39 back in the late 90's, I had my original pumps rebuilt by Skip. I also installed a pusher electric fan in the front of my radiator, especially for parades back in PA. For the most part, I never overheated.

In getting ready to move to Southern AZ. I also replaced the original radiator with a Walker and did a pretty through EvapoRust flush.

I mention this because here in the Tucson area from late May through September, there are times when pumps, extra fans, magic potions, etc. will not keep you from the dreaded vapor lock by the side of the road in our beloved flatheads.

So, during the hottest part of our days here, I've found that keeping those high efficient water pumps in the garage and tuning in here on the Ford Barn is my never fails solution to flathead overheating!!

[G.M.]

Originally Posted by RKS.PA

When I rebuilt my '39 back in the late 90's, I had my original pumps rebuilt by Skip. I also installed a pusher electric fan in the front of my radiator, especially for parades back in PA. For the most part, I never overheated.

In getting ready to move to Southern AZ. I also replaced the original radiator with a Walker and did a pretty through EvapoRust flush.

I mention this because here in the Tucson area from late May through September, there are times when pumps, extra fans, magic potions, etc. will not keep you from the dreaded vapor lock by the side of the road in our beloved flatheads.

So, during the hottest part of our days here, I've found that keeping those high efficient water pumps in the garage and tuning in here on the Ford Barn is my never fails solution to flathead overheating!!

If you put a small fuel return line from right after the fuel pump back into the filler neck you will never get vapor lock. You nee a needle valve to adjust
the amount of fuel being returned. To much returned and it will act like a governor at high speed, you will run out of gas. I attached a picture of where
the fuel returns into the filler neck. G.M.

[drolston]

My '41 overheats if it sits at idle for long on a hot day. Temp also comes up on a long climb. I put in Dennis Carpenter water pumps with modified impellers that are supposed to help water flow, especially at idle. I seems to take longer now, but still overheats in traffic on a hot day. Losing coolant at every stoplight and it doesn't take long for coolant to drop below the bottom of the top tank; then the overheating escalates. I just added coolant recovery tank to capture and return what blows out. I am running an aluminum radiator with a modern 7 lb pressure cap.

I also blocked airflow around the radiator with foam stuffed along the sides and the bottom. I fabricated a baffle from 3/8 plywood for between the top of the grill and the radiator tank. A little tacky, but it solved cooling on a long climb and helped some at idle.

In the picture you can also see that I added a shroud (partial) and a spacer to get the fan closer too the radiator. Drilled holes in thermostats to get them to open sooner. No individual change helped a lot, but collectively the cooling situation is now tolerable.

If I weren't such a stickler for "classic hot rod" I could have just put on a big electric fan and been done.

[RKS.PA]

Originally Posted by G.M.

If you put a small fuel return line from right after the fuel pump back into the filler neck you will never get vapor lock. You nee a needle valve to adjust
the amount of fuel being returned. To much returned and it will act like a governor at high speed, you will run out of gas. I attached a picture of where
the fuel returns into the filler neck. G.M.

George, this the only thing I haven't tried and from this and earlier explanations you've provided, I see how this can beat vapor lock by keeping a cooler supply of gasoline circulating to the carburetor.



If I ever need to drive our flatheads here in the AZ summer mid-day heat, this is the way I'm going. Thanks for your advice.



Enjoy your time in the Honeybrook part of Chester County PA!! Seems like it might be about time for you to migrate north to your summer location and the weather there should be getting pretty nice!!


Regards.....Dick.

[philipswanson]

What ever happened to the electric fuel pump idea for preventing vapor lock?

[G.M.]

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Originally Posted by RKS.PA

George, this the only thing I haven't tried and from this and earlier explanations you've provided, I see how this can beat vapor lock by keeping a cooler supply of gasoline circulating to the carburetor.



If I ever need to drive our flatheads here in the AZ summer mid-day heat, this is the way I'm going. Thanks for your advice.



Enjoy your time in the Honeybrook part of Chester County PA!! Seems like it might be about time for you to migrate north to your summer location and the weather there should be getting pretty nice!!


Regards.....Dick.

..Hi Dick, my wife passed away a couple years ago and I won't be going to
Honey Brook for the summer any more. I am coming up for two weeks on May 12th. I have my 74 GMC diesel P/U that I put a new engine in a few years ago to finish, had it running but some wiring left. I still have a 50's
32 roadster, 39 convertible sedan, and 39 convertible up there to either
sell or give to my grandson who has interest in them. He has helped me
for years and can keep them running. I will have to give him the house
and garage so he has a place to keep them. G.M.

[deuce_roadster]

George, If the grandson isn't interested---I am available for adoption.

[flatheadmurre]

Originally Posted by drolston

My '41 overheats if it sits at idle for long on a hot day. Temp also comes up on a long climb. I put in Dennis Carpenter water pumps with modified impellers that are supposed to help water flow, especially at idle. I seems to take longer now, but still overheats in traffic on a hot day. Losing coolant at every stoplight and it doesn't take long for coolant to drop below the bottom of the top tank; then the overheating escalates. I just added coolant recovery tank to capture and return what blows out. I am running an aluminum radiator with a modern 7 lb pressure cap.

I also blocked airflow around the radiator with foam stuffed along the sides and the bottom. I fabricated a baffle from 3/8 plywood for between the top of the grill and the radiator tank. A little tacky, but it solved cooling on a long climb and helped some at idle.

In the picture you can also see that I added a shroud (partial) and a spacer to get the fan closer too the radiator. Drilled holes in thermostats to get them to open sooner. No individual change helped a lot, but collectively the cooling situation is now tolerable.

If I weren't such a stickler for "classic hot rod" I could have just put on a big electric fan and been done.

The fins on the new "hi effiency" are so close together and the thickness of the core makes it much harder for the fan to get air through it.
You probably have to ad one of them flex fans that has a more agressive angle at low rpm to get enough air through it.
Or try and hide a pushing fan in front of radiator out of sight.