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Electric Fuel Pump and Vacuum Wipers-- How Bad?


Guest kencary

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Guest kencary

My newly acquired '51 Pontiac 8 has an aftermarket electic fuell pump. I am happy about this as it helps prevent vapor locks that these cars are prone to on modern low boiling point gas.

The problem is, that there is no vacuum booster for the wipers. How bad are the wipers when run without a vacuum booster?

I don't plan to drive in the rain, but obviously it happens. I don't live in a hilly area so my main problem would be accelerating with the wipers on.

Can anybody share their experience here? If it is really bad, I may want to look for a 6V electric conversion.

Ken

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The vacuum wipers are fine if they are in good shape. The only problem is vacuum disappears and the wipers slow down when you step on the gas.

The solution for this is a double decker fuel pump. They put a vacuum pump on top of the fuel pump, no more problem.

This fuel pump was an option when your car was new. Up until a few years ago they were available from any parts store.

The vacuum hose goes from the manifold to the pump, and then to the wipers. The pump only kicks in when the vacuum drops off, otherwise they run on manifold vacuum.

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Guest kencary
The vacuum wipers are fine if they are in good shape. The only problem is vacuum disappears and the wipers slow down when you step on the gas.

The solution for this is a double decker fuel pump. They put a vacuum pump on top of the fuel pump, no more problem.

This fuel pump was an option when your car was new. Up until a few years ago they were available from any parts store.

The vacuum hose goes from the manifold to the pump, and then to the wipers. The pump only kicks in when the vacuum drops off, otherwise they run on manifold vacuum.

That is the problem. With an electric fuel pump there is no wiper boosting fuel pump. I suppose I could put back the old fuel pump and only hook up the booster side.

Ken

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If your car is prone to vapor lock eventually that will happen.Modern fuel flash point is about 147F. fully 10 less than when the Ac or Carter dual action was new.That aside there are drawbacks to all choices. What are the summer temps where you drive, is it stop and go? If you get vapor fuel starvation it is dangerous, as you lose control in the traffic flow. So, you can put back the mech pump, and put a electric one in line.The question here is, will you restrict the suction draw from the mech pump and need to run the electric anyway? Also if a leak develops in the mech pump than you could have gas pumped into the crankcase by the elec pump. None of this will happen with the elec alone.Use a pressure reg in line. One other thought is to"hollow out" a mech pump, run the fuel and vacuum line though it with the ARM removed and the engine hole blocked. Then you still have the wiper situation( booster is disabled). On my Hudson I must floor it to get the wipers to stop fully, so, add a vacuum tank if the presence of it won't bother you or the judges. They cost less than $20. Easy to remove for AACA meets and the judges can't tell with the lines all appear as correct.

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....add a vacuum tank if the presence of it won't bother you or the judges. They cost less than $20. Easy to remove for AACA meets and the judges can't tell with the lines all appear as correct.

Hi Ken,

Vacuum tanks are available on eBay anywhere from about $10 up. However most of the less expensive ones tend to be newer & small, like this one: 1998 - 2005 REGAL IMPALA INTRIGUE VACUUM TANK NEW OEM:eBay Motors (item 120501158314 end time Dec-09-09 18:15:51 PST) , and may not hold enough vacuum for your needs. Try to find an older application, like from a car with vacuum operated hidden headlights or windshield washer system (C1 Corvette washer vac. tanks run about $150.). They'll generally be much larger.

If you want a more "vintage" solution, you might try to do something with tomato juice cans. Check out this old page from a 1947 Popular Science magazine: Popular Science - Google Books . :cool: Just be sure to have some sort of check valve between the tank and the manifold, otherwise you'll lose most of what you saved back into the intake.

BTW, I find using Rain-X liberally reduces the need for wipers substantially. If it existed in 1965 I think drive-in movies would've never gone into decline!:)

Edited by Dave@Moon
typing too late at night! (see edit history)
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Guest kencary
Hi Ken,

Vacuum tanks are available on eBay anywhere from about $10 up. However most of the less expensive ones tend to be newer & small, like this one: 1998 - 2005 REGAL IMPALA INTRIGUE VACUUM TANK NEW OEM:eBay Motors (item 120501158314 end time Dec-09-09 18:15:51 PST) , and may not hold enough vacuum for your needs. Try to find an older application, like from a car with vacuum operated hidden headlights or windshield washer system (C1 Corvette washer vac. tanks run about $150.). They'll generally be much larger.

If you want a more "vintage" solution, you might try to do something with tomato juice cans. Check out this old page from a 1947 Popular Science magazine: Popular Science - Google Books . :cool: Just be sure to have some sort of check valve between the tank and the manifold, otherwise you'll lose most of what you saved back into the intake.

BTW, I find using Rain-X liberally reduces the need for wipers substantially. If it existed in 1965 I think drive-in movies would've never gone into decline!:)

Dave,

Did you know that this was me when you replied to this post?

After your last e-mail I realize that I have been reading your posts for some time now.

Ken

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A mechanical pump will draw thru an electric pump (and vice versa) no problem.

If it was mine I would put on the original combination fuel/vacuum pump and leave the electric since you have it. Draw thru the electric pump.Put a switch on the dash in case you need the electric for emergencies such as, hard starting or hot weather vapor lock.

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Dave,

Did you know that this was me when you replied to this post?

After your last e-mail I realize that I have been reading your posts for some time now.

Ken

Since we both used roughly the same format to derive our pen names, I guessed pretty quick when you came online here that it was you.:) (Timing & topics were a big help as well.) Most of your first posts came while I was away for the holiday, so I didn't get to respond to any until now.

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