Double action fuel pump

tubman

tubman

Well-known member
I was going through a bunch of parts and came across a brand new "Double Action" fuel pump (I think they came on Mercury's). I am considering putting it on my '51 Ford to see if it makes the windshield wipers work better. I have heard some place that they are hard on camshafts because of the extra diaphragm that has to be actuated. Is there anything to this? Was the Mercury camshaft any different to account for the extra pressure? Anybody have any information/comments/ideas?

Also, it has two extra vacuum ports; does anyone know how it's plumbed? Mercury owners?
 
Motor vacuum goes into the pump and from there to vipers.
No difference in fuel pump lobe profile between the different "8BA" cams i have.
 
I thought the '51 fords came with the dual pump. My '50 had one on it when I bought it 18 yrs ago and its still works. The wipers are a bit better with the dual than the single. If I had one I would put it on.
 
They did indeed come on Mercury's as well as Fords.
There was some talk that during a period of time, because of the extra spring pressure, they caused some early failure on the pump lobe.
Don't know if it was a camshaft issue or something else.
After installing electric wipers I removed my double pumper.
If there is any doubt about the extra spring pressure, try moving the arm and compare with a single pumper.
 
Make sure you buy a new pump, not an "old stock" one that's been on the shelf for 40 years. I had one on the 6 cylinder in my avatar. On a road trip back from Mississippi my recently rebuilt engine started smoking real bad and I went through 3-4 quarts of oil in the last 300 miles. Preparing for another engine teardown, I got home to find that I had a tear in the vacuum diaphragm and was pulling oil out of the engine and burning it through the engine. Had a new single action pump in my spares. Put it on and the problem went away. That was over 30,000 miles ago. Ended up keeping the single action pump and buying a new wiper motor.
 
51 Merc said it, you must use a cheater bar to move the arm on a 2x action pump. I've built these pumps for concourse cars Mercs and '51 up Ford hard tops , converts and sw's, I eliminate the vac portion. Most push rods from 2x pump equipped cars are bent from slight to way over slight.
Charlie ny
 
If your car is not a trailer queen and you have converted to 12 V., try an electric vacuum pump from an '80's era GM compact. They were so anemic that they needed an external vacuum source to run the power brakes! This was a remote self contained pump that mounted under the battery tray. I'll have to look up the exact models that used it.
OK ,found some: '84-85 Celebrity with 2.8 V6 and its clones from Pontiac, Buick, Olds and the infamous Cadillac Cimarron. An online search will turn up others.
 
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Dad bought a new 51 Ford with a dual action pump, drove it 122,000 miles, 10 foot ..you couldn't hear the engine running
 
All of this has me leaning towards not using it. "JT Ford", when you say it made the wipers perform a "bit better", do you mean it was just a slight increase? The wipers on my car are what I would call "adequate" with the single action pump; I would have thought that a Double Action unit would make a big difference. If not, why make the switch?

I think I will start experimenting with vacuum reservoirs; I have one on my '68 Corvette, and it seems to handle everything (headlights and wiper door) just fine.
 
Hi tubman, not a big difference on mine either. After reading about cam issues i may put a new single on during this rebuild. You in Fla yet? mike
 
Mike, good to get more info. This looks like a non-starter for me. Anybody want to buy a nice double action pump? I'm stuck in Minnesota for the winter because of circumstances beyond my control. It's the first time in 15 years, and of course, we're having the coldest winter in recent memory. I am getting a few things done in the shop, though.
 
I put a 49 merc in the 46 big truck, made all the difference with the vacuum wipers, didn't have to lift the throttle to get a wiper sweep climbing a hill, they slowed down some but wouldnt stop ---the 49 merc made all the difference climbing hills too
 
How often do we drive these cars in the rain anyhoose? Rainex 4 me & it seems to lube the windshield so the blades move easier. ?? Kinda. I'll bet higher rpm may help the d a pump make more vac. too ? mike
 
Until you've been on the highway in the rain with a car up your *** and having to decide whether to let up on the throttle to see or keep going to keep him out of your bumper, you'll never know the struggle.
Somewhere around I have a Ford service bulletin from 1949 warning against these aftermarket devices, even though they were Ford's solution in 1951.
 
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