Classic cars forum & vehicle restoration.
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rcx822
Joined: 31 Dec 2010
Posts: 112
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 Posted: Sat Oct 18, 2014 7:57 pm Post subject: Does it matter where the windscreen washer valve goes? |
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| Should it be near the pump, or further down the hose, or doesn't matter? |
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47Jag
Joined: 26 Jun 2008
Posts: 1480
Location: Bothwell, Scotland
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| Posted: Sat Oct 18, 2014 11:31 pm Post subject: |
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I reckon the valve should be on the hose on the reservoir. That way the hoses will always be 'charged' with water.
Art |
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Peter_L
Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.
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| Posted: Sun Oct 19, 2014 1:43 pm Post subject: |
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| 47Jag wrote: | I reckon the valve should be on the hose on the reservoir. That way the hoses will always be 'charged' with water.
Art |
Agree: The weight of the water in the tube keeps the non-return closed. |
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Old Wrench
Joined: 23 Dec 2013
Posts: 226
Location: Essex and France
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| Posted: Sun Oct 19, 2014 2:53 pm Post subject: |
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If the one-way valve is secure, then it doesn't actually matter. Mainly since whether a mickey mouse rubber bellows "water pistol" pump a la Mini, Morris 1100 etc and later electric pressure pumps are all self-priming.
The old Trico-Folberth reservoirs had a "Foot Valve" right at the bottom of the pick-up tube.
However, the Morris 1100 had a small brass bodied valve with a glass ball, pushed into the plastic pipe immediately before the pump.
_________________
Well, apart from that, did you enjoy the play, Mrs Lincoln? |
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rcx822
Joined: 31 Dec 2010
Posts: 112
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| Posted: Mon Oct 20, 2014 10:32 am Post subject: |
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| Old Wrench wrote: | If the one-way valve is secure, then it doesn't actually matter. Mainly since whether a mickey mouse rubber bellows "water pistol" pump a la Mini, Morris 1100 etc and later electric pressure pumps are all self-priming.
The old Trico-Folberth reservoirs had a "Foot Valve" right at the bottom of the pick-up tube.
However, the Morris 1100 had a small brass bodied valve with a glass ball, pushed into the plastic pipe immediately before the pump. |
Hi old wrench. What do you mean that later electric pumps are self priming? What priming do they need to do?
My car is actually not quite classic yet, it's a 1990's Suzuki Vitara so it has an electric pump. I come to this forum because the real knowledge is here among the car restorers, more so that on forums for modern cars, and I am doing a full overhaul/semi restoration.
I found a valve from another Suzuki and I also bought one off a modern Porsche. Both of them have very high resistance which is concerning. |
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Old Wrench
Joined: 23 Dec 2013
Posts: 226
Location: Essex and France
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| Posted: Mon Oct 20, 2014 1:37 pm Post subject: |
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| rcx822 wrote: |
Hi old wrench. What do you mean that later electric pumps are self priming? What priming do they need to do?
My car is actually not quite classic yet, it's a 1990's Suzuki Vitara so it has an electric pump. I come to this forum because the real knowledge is here among the car restorers, more so that on forums for modern cars, and I am doing a full overhaul/semi restoration.
I found a valve from another Suzuki and I also bought one off a modern Porsche. Both of them have very high resistance which is concerning. |
Some fluid pumps need fluid introduced into the pump, static, before they will actually (i) Suck; and (ii) Output fluid under pressure.
The old Rubber Bladder type pumps would need to be "pumped" for a bit, before water under pressure, in spurts!, sprayed onto the screen.
Whilst a non-return valve is not essential in a self-priming electric pump, operating these with no water for an extended period can damage the impeller in the pump body: additionally, when we jump into our car first thing, we expect the screen washers to work; immediately.
The One Way Valve prevents water draining back from the scuttle, into the reservoir (which is inevitably lower than the scuttle).
The one way valves in modern cars is usually in the bottle or incorporated into the pump.
Many cars have two separate pumps, now: one for the screen and another for the headlamp wipers.
_________________
Well, apart from that, did you enjoy the play, Mrs Lincoln? |
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Peter_L
Joined: 10 Apr 2008
Posts: 2680
Location: New Brunswick. Canada.
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| Posted: Mon Oct 20, 2014 3:21 pm Post subject: |
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Rotary pumps come in three (maybe more) categories.
Submersed or below the input water line.
Above the water line and self priming
Above the water line and not self priming.
Pumps that have a hard impellor and stator, need to have a small clearance between the moving and stationary parts. This clearance will usually prevent the pump from pushing the air out of the discharge thus creating a vacuum behind into which the water will flow, once the water reaches the pump, the water creates a seal between the moving parts and the impellor forces the water out of the discharge.
If the pump impellor, stator is immersed, such as below the water line, then water will fill the cavities. (Discharge has to be open)
Pumps that have flexible stator and/or rotor, can allow the two parts to be in contact and as such will push the air out of the pump and form the vacuum behind that will then fill with water.
Some Ford, with rear window washers, use bi-directional pumps built into the lowest point of the reservoir. These pumps have two outlets. One goes to the windscreen and one to the rear screen. The one pump will send water to front or rear depending on which way the pump rotates.
Any non-return valve will introduce a constriction in flow.
New, or 100% dried out self priming pumps, are better served if liquid is introduced into the pump prior to starting.
Hope this helps explain some of the differences, Google will guide you to many diagrams and technical information.
E&OE
Peter L |
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