Vacuum Wiper - Holly 4bbl - electric wiper switch

R

Red98

Member
1950 Merc -

My new engine will have the fuel pump capped off hence not have the vacuum provided by it but will only have what vacuum the 4bbl carb provides. Is that adequate to power the wipers?

Should it prove inadequate I must change to electric wiper motors from NewPort. I have delayed reinstalling my radio until I find out.

If anyone has done this mod I have another question, what did you do for a wiper switch as the original dash switch isn't amenable to electricity? Solving the switch question is more troubling than the cost of the NewPort wiper.
 
Fords of that era did not have a dual action fuel pump; the wipers ran off of manifold vacuum only. I have a '51 Ford and have gone through the vacuum wipers so they work about as well as they can. I feel they are perfectly adequate for my purposes. Of course, I try not to drive on rainy days, but I have been caught in a shower or two and the wiper perfromance was satisfactory. It all depends on whether the intake manifold you are using has a port for the wipers (most do, and one can be added if necessary).

I have toyed with the idea of adding a vacuum resevoir or perhaps even an auxialiary vacumm oump, but up until now, there has been nothing to motivate me further down that road.
 
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My '40 has a Holley 390, and the wipers are adequately supplied from a port on the Offenhauser intake manifold. Both vehicle and wiper speed are conveniently controlled by the same pedal on the floor.
 
A lot of carburetor vacuum ports are regulated, not something you would want to use for windshield wipers. The vacuum wipers need to be connected to manifold vacuum.
 
I should think all you need is the plate that goes under the carb. the one with a port
for PVC valve or power brake booster. Plenty of vac. there especially for wipers.
 
Red98 said:
1950 Merc -

My new engine will have the fuel pump capped off hence not have the vacuum provided by it but will only have what vacuum the 4bbl carb provides. Is that adequate to power the wipers?

Should it prove inadequate I must change to electric wiper motors from NewPort. I have delayed reinstalling my radio until I find out.

If anyone has done this mod I have another question, what did you do for a wiper switch as the original dash switch isn't amenable to electricity? Solving the switch question is more troubling than the cost of the NewPort wiper.
Click to expand...
Remove the switch that is for the vacuum wiper and use the same hole for the electric switch. Use the knob off the original switch and place it on the electric switch.
 
Red98 said:
1950 Merc -

My new engine will have the fuel pump capped off hence not have the vacuum provided by it but will only have what vacuum the 4bbl carb provides. Is that adequate to power the wipers?

Should it prove inadequate I must change to electric wiper motors from NewPort. I have delayed reinstalling my radio until I find out.

If anyone has done this mod I have another question, what did you do for a wiper switch as the original dash switch isn't amenable to electricity? Solving the switch question is more troubling than the cost of the NewPort wiper.
Click to expand...
You did not say which 4bbl carb you are using but most have a manifold vacuum port that is used for a PCV system, this port would be an adequate source to operate the wipers.
As previously stated, the electric wiper switch can be mounted in the original vacuum switch location and the original wiper knob will fit it.
(did the same thing on my '51)
 
It would depend on engine base line running vacuum. A worn engine , not tuned properly or hi perf camshaft will make a big difference in performance. So will gear ratio and the region you drive , mountains etc .
 
I just replaced the vacuum wipers with 2 speed electrics, used the hole in dash for radio antenna for switch. No more patting pedal to get wiped. Al
 
Your wipers should run off a tap somewhere on the intake manifold. Ford once added a vacuum reservoir to give the system some help. It was just a large tin can such as juice is sold in. Solder a tap into the top of the can, and be sure any openings in the can are made air tight. Using a "tee", run one hose from the manifold to the tee, with the other to the wipers. It isn't perfect, but does make a difference. The original had a plastic check valve in the line to the manifold. I have used one from a hot tub dealer where they are sold to protect ozone generators.
 
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