Ques. about 8BA fuel/ Vac. pump

BrianCT

BrianCT

Well-known member
I am thinking about using a fuel/vac. pump on my 8BA to run the wipers.
Is it much of an improvement over manifold vacuum ?
Will I need to install a vacuum canister? I noticed that the vacuum portion
has two threaded holes, both marked in. Any idea why there would be two?
Brian
 
I have heard the dual action pumps are hard on the camshaft. A vacuum resevoir itself should be sufficient. I have a O/T '68 Corvette with a vacuum wiper door and headlights. It has a vacuum resevoir (sp?) that is not connected to the fuel pump and it is enough to run them through a couple of cycles.
 
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the vacuum pump will make a lot of difference on acceleration, the wipers wont quit working on acceleration
 
Brian,
It is quite impossible to actuate a dual action pump by hand. The arm is
massive to handle the internal resistance. Do not be surprised if you find this brute
bends your pushrod. I'm only guessing here but it seems that Ford might have
supplied a beefier p/r for this application.
This got to be very buzzy at the Gettysburg Meet last week , the judges
were eye balling certain Mercs, fancier Fords and Fordomatic equipped cars that
were factory equipped with dual action pumps.
For concourse cars I suggest building the dual action pump with the
vac pump portion disabled.
Charlie ny
 
The one thing I found out when I got a new double action Airtex pump 9597, is that they put out 7 1/2 lbs of fuel pressure which blew the power valve out. Had to use a regulator until after 1500 miles of use when the cheap Chinese spring weakened and the pressure dropped to 4 lbs, so I added 3 more pump stand gaskets and got down to 2 1/2 lbs and took the regulator off. The second pump also had 7 1/2 lbs. Uses same rod as manual pump.
Don
 
Years ago, I installed a dual action fuel pump on our '53 Sunliner, in the hope that it would improve the windshield wiper performance... As I recall, once the pump was installed, I was unable to shut the wipers off... At the time, I was told by an older auto mechanic, that the dual action pump used a different wiper motor switch... I never did investigate to see if I could fine a different switch, I just replaced the dual action with a regular fuel pump. Our '49 Cosmopolitan has a dual action fuel pump but I've not gotten to the point (on the car) where I'll be able to try the wipers.
 
When the 49 Merc was put into the 46 big truch no modifications were made to the wiper system, the hose was just hooked to the pump, it was a miracle, ---no hill too steep(the truck traveled with a 2 ton load) ,and the wipers never stopped
 
Have a double action pump on a Little Ford here, 60 ci (997cc) it's basically the same main pump body as the late flathead pump.
This little dude has vacuum wipers that would stop with almost any amount of gas pedal action. With the double pump, they work fantastic! Fully speed adjustable from " only just see them move" all the way to "are they gonna fly off".
If it works good on this little Ford, it's goona work on a Flathead Ford.
They do have brutal spring pressure in the vacuum side, difficult to operate it with your hands.
Go for it.
Martin.
 
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Big Red 51 said:
The one thing I found out when I got a new double action Airtex pump 9597, is that they put out 7 1/2 lbs of fuel pressure which blew the power valve out. Had to use a regulator until after 1500 miles of use when the cheap Chinese spring weakened and the pressure dropped to 4 lbs, so I added 3 more pump stand gaskets and got down to 2 1/2 lbs and took the regulator off. The second pump also had 7 1/2 lbs. Uses same rod as manual pump.
Don
Click to expand...

I gota ask, how did the pump blow the power valve out?
Can't, can it?
Martin.
 
No. Too much pressure would keep the needle valve from sealing. The fuel bowls are vented, not pressurized, as you no doubt know.
 
Thanks everyone. This brought out a lot of interesting information.
I have an AC pump and was going to look for an ethanol proof diaphragm.
I think this goes on the back burner for now.
By the way, my 8BA push rod is beefier than a 59 AB.
Brian
 
Martin, when I installed the new pump the PV didn't work and the PV rubber was ruptured. Kenct thought also that it was the high pressure. Could have been the needle. I have OD,hence, the dbl action. Wipers do work great. Don
 
Thanks for reply Don.
I think what you had yourself there was a coincidence. As 1952 Henry said, to much pressure fuel side would flood the float bowl (by overpowering the float needle) and then flow out the vent tube/hole depending on carb type. If it was possible to presurise the float bowl with to high fuel pressure, it would force the power valve shut, and seal metal to metal. The rubber wouldn't be under stress.
Only seen ruptured power valves by backfiring through the carb, sometimes it only takes one sneeze, with a Big air cleaner you might not even hear it.
Glad your wipers work well, they should do with the vacuum pump. I fancy to many folk pull all this good stuff out, and replace with electrical stuff without giving the original stuff a chance.
I can include me in there as I fitted electric wipers in my truck, but I had that stuff laying around and didn't have the vacuum stuff. So for me at that time it was what I had to do. One day it may get pulled out and vacuum stuff put in. With the vacuum stuff on the little Ford, you can slow the wipers down enough that you don't have to keep turning them on and off in light rain. Very nearly as good as intermittent wipers, which my truck hasn't got.
Brian. The 8BA pushrod is beefier than the early pushrods, also made from three pieces, a tube and two ends. Light aswell.
Martin.
 
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