Vacuum Fuel Pump vs. Electric Fuel Pump

[Guest Jpcrone]

I first wanted to acknowledge how helpful this discussion forum has been helping me restore my 1950 Buick Special. There is alot knowledge being shared. Thank you.

 

My next step is replacing the fuel pump... I'd like advice on the pros and cons of a traditional vacuum fuel pump vs. an electric fuel pump.

 

I have the original carburetor on the car. But I did purchase a 6 volt to 12 volt conversion kit. The kit came with an electric windshield wiper reducer.

 

How does that impact my fuel pump decision? 

[Ben Bruce aka First Born]

 Some of those parts are redundant. The wiper motor reducer is one. No place to use it on any 6V conversion. 

  On the fuel pump, the vacuum part is just a booster. Supposed to help with the wiper operation when the throttle is opened. They helped, not much.  Most folks that stay with the carb stay with the original fuel pump. The electric one can be added later if [when]  needed.

 

  Ben

Edited April 10, 2017 by Ben Bruce aka First Born (see edit history)

[60FlatTop]

Maybe they will swap a $19,95 value fire extinguisher for the wiper reducer.

Bernie

[JamesBulldogMiller55Buick]

What's the reducer going to for you?

the windshield wiper voltage reducer will reduce the voltage from 12v to 6v for the windshield wipers' vacuum motor ......(?)

[NTX5467]

tSeems like there IS a 6V electric fuel pump available somewhere?  Use it in cases of possible vapor lock in hot weather and slow traffic situations.  When not needed, leave it in the "OFF" mode.

 

In the older vacuum wiper motors, there is a grease in there that seals the leather to the housing as it moves.  With time and age, the grease can become "stiff" and make the wipers work slow.  Reputedly, adding a small amount of brake fluid into the vacuum cavity can "freshen" the grease so that things move better.

 

NTX5467

Edited April 11, 2017 by NTX5467 (see edit history)

[Guest Jpcrone]

I was told that the vacuum fuel pump also tied into the wipers. I didn't know if I need to keep with the vacuum style fuel pump or if I could convert to an electronic fuel pump. I obviously would like to the wipers functional.

[JFranklin]

The wipers will work with any manifold vacuum port.

[NTX5467]

The two-stage fuel pump is kind of like two fuel pumps stacked together, except one sucks fuel from the fuel tank (for the engine) and the other one builds vacuum to help the wipers work consistently fast.  I suspect that you could run the bottom (fuel) half "dry" and maintain the upper half pumping vacuum as it does now.

 

Not all vehicle with vacuum-operated windshield wipers had the two-stage fuel pump.  On those vehicles, the amount of manifold vacuum determined how fast the wipers wiped.  On harder acceleration or a decent hill could lower the intake manifold vacuum level such that the wipers would slow down markedly or stop in mid-wipe . . . until manifold vacuum levels increased and then they'd work again.  The vacuum side of the two-stage fuel pump was supposed to make wiper operation more consistent.

 

It could also be necessary to ensure the wiper mechanism operated with as little "power" as it could.  Other than the grease in the vacuum chamber, some lubrication on the wiper linkage would certainly help, too, I suspect. 

 

NTX5467

[Beemon]

My grandfather installed an old SW vacuum gauge under the dash and I've kept it in my car. When I had vacuum wipers, it seemed climbing hills the vacuum gauge would drop to about 6"Hg and the wipers would stop. This base line 6"Hg is what the pump put out under load, where manifold vacuum is close to 0"Hg, so even it wasn't enough to keep them going. You could even try using a vacuum reservoir, but it would most likely run out before you let off the throttle. Land isn't flat out here where I live and it rains a lot, so I got rid of the system all together.

[60FlatTop]

I was curious. Here is the windshield wiper reducer from that kit.

https://www.vintageautogarage.com/productdetails_popup.asp?productcode=V12873

 

Curious again, why are you converting it?

Bernie

[A. Ballard 35R]

Why didn't you buy a newer car that had all these modifications as standard equipment?

[Guest Jpcrone]

My initial question was more related to making sure I purchased the correct type of fuel pump so it wouldnt negatively impact my wipers. Thank you for the links and comments.

[old-tank]

1 hour ago, A. Ballard 35R said:

Why didn't you buy a newer car that had all these modifications as standard equipment?

To me this comes across as pompous and mean spirited.  There is nothing wrong with a member asking for help to personalize his car to be a safe and dependable driver.

[A. Ballard 35R]

29 minutes ago, old-tank said:

To me this comes across as pompous and mean spirited.  There is nothing wrong with a member asking for help to personalize his car to be a safe and dependable driver.

My comment was in way pompous but simply a reasonable question since there are many newer but still antique cars that have the modifications desired. The changes described are not personalized such as paint color, etc., but modifications. I will certainly defend his right to modify a vehicle as much as he wants but shouldn't we keep in mind that the AACA stresses originality and authenticity?  

[A. Ballard 35R]

Just remembered that this Forum serves as the forum for the BCA also and not just for AACA. Consequently, my comments regarding AACA qualifications are not related to Jpcrone's questions. My apologies.

[F&J]

4 hours ago, Jpcrone said:

My initial question was more related to making sure I purchased the correct type of fuel pump so it wouldnt negatively impact my wipers. Thank you for the links and comments.

 

I use vacuum wipers.  I got lucky to find a NOS vacuum wiper motor.   I use the stock 1955 Olds dual diaphragm fuel pump that assists the wipers.  It works fine as I just got caught in rain last weekend.  I'd never used them before that day, as I don't want to run in the rain or snow.

 

But, I also use an electric fuel pump mounted near the tank.  It's output line feeds the inlet of the original stock pump.  The reason some people use "both" types of pumps on one car is quite simple:   With modern gas that now has increasing percentage of methanol/alcohol, your carburetor dries out if you don't use the car daily.  So, turn the electric pump on to prime the fuel bowl in the carb, then when you go to start the engine, you don't need to crank forever to get gas back in the bowl.

 

.

[Guest]

I always thought a "vacuum fuel pump"  was a stewart, Kingston or similar that operated by using the engine vacuum to draw the gas from the tank in the rear.  It appears here we are talking about a mechanical fuel pump or a mechanical fuel pump with vacuum booster assist.

I had two 53 Buicks at the same time. One had the plain mechanical pump and the other had the combination fuel/vacuum booster pump.  In ordinary driving under partial acceleration the combination pump was an improvement.  On a steep hill unless I was driving 60 in second gear the vacuum boost was no help.

I still prefer driving my 30 Pontiac but until my wife bought a new Sonota, the 53 Buicks were the best car driving car I ever had even surpassing my 11 series Packard.

Edited April 12, 2017 by Guest (see edit history)

[60FlatTop]

 

I never added an electric fuel pump.

But if I did:

 

I would install an inertia switch and an inclinometer  switch in series.

 

"Keep the roof up and the wheels down, My Friend."

Bernie

Edited April 11, 2017 by 60FlatTop (see edit history)

[RivNut]

3 hours ago, 60FlatTop said:

 

I would install an inertia switch and an inclinometer  switch in series.

 

 

Now you're talking about the shoulder belt restraining system on the Chrysler Sebring convertibles.  What a PITA.  I was going to install them in the Riv but after figuring out what all it took to make them work, I abandoned the project.

 

Ed

[NTX5467]

Inertia reel seat belt retractors began being used by GM in the middle 1980s.  Sometimes, unless you stopped very quick and the retractor locked, you didn't know they were there.  Others were more aggressive, by observation.  And THEN there are the pyrotechnic "explosive charge" seat belt tensioners which "fire" to keep the belt tight in a collision . . . single use only..

 

What about adapting an under-dash THM400 kickdown switch to run the electric aux fuel pump past a certain amount of footfeed travel?  That should be pretty easy and invisible.

 

We have to remember the general driving conditions/environment of when our cars were designed and built.  It was a different world back then!  Some vehicles did better in some environments than others did, by observation . . . whether it was due to higher temperatures or keeping the windows clear in humid conditions.  As things have progressed, the need for upgrades/enhancements (hopefully well-engineered and INCOGNITO) might deserve consideration.

 

NTX5467

[60FlatTop]

Does the pump continue to run should there be an accident?

[RivNut]

The difference in the Chrysler belt and others is that the Chrysler belt does not have an inertia reel.  It has a solenoid that has 12 volts going to it, That solenoid, when de-activated by either a sensor that senses a drastic change of momentum or by another sensor activated by a change in the angle the car takes 12 volts from the solenoid.  When either sensor is activated, it signals the solenoid, the belt is stopped in the position it's in at the moment.  Your body has unlimited movement until there's no longer 12 volts supplied to the solenoid.  It's even hooked to the dome light switch so the belt can be moved when getting in and out of the car. If your car doesn't have 12 going to those sensors, the belts cannot be budged. So collisions or rollovers, or panic braking will lock the belt.  Otherwise it's as if there's nothing, the belt moves freely.  

 

Pretty ingenious, but a pain in the but to retrofit.  That's how Chrysler built an integrated shoulder belt into their seats, nothing fastened to the body or the frame.

[NTX5467]

3 hours ago, 60FlatTop said:

Does the pump continue to run should there be an accident?

 

Many factory elec fuel pumps are switched via the oil pressure switch on the engine.  Others, as many Fords, have an inertia switch (with reset mechanism in the rear section of the car), kind of like an SRS airbag deployment sensor.

 

NTX5467

[Beemon]

I'm pretty sure Bernie was talking about an inertia switch for the fuel pump and not the seat belts.