Joined: Aug 2017 Posts: 691 Threads: 37
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Location: The Scottish Border
The FZB updraft carb has a vacuum take off
for a Lucas vacuum motor.
Has anyone used a Lucas vacuum motor with an SU carb ?
If so where’s the best place to make a takeoff?
Alternatively have a quite rare P&H electric wiper motor, ( I’ve never seen another one)
And think I’ve seen it mounted on a period GE photograph?
Anyone else used a P&H wipermotor?
Course I may not take the car out in the rain. :-) anyway !
Regards
Bill G
Based near the Scottish Border,
Joined: Aug 2017 Posts: 2,748 Threads: 31
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Location: Auckland, NZ
Although it is the set up on my RP, th combination of an SU and vacuum wiper is a curious contradiction. (in fairness at the revs then considered normal the pressure drop thru zeniths is also very small. (The restrictive effect of carbs is meaured by the pressure drop in inches of mercury, which is exactly what the wiper does but in strokes per minute/hour!) Fortunately on my car eons ago a manual operating lever had been added, similar later cars.
When driving moderns in the rain always impressed even cf cars of the 60s.
Even owners of performance cars of the time (Ford 10!) might not be impressed by air tanks. Dunno if they had a manual lever but overtaking tricky without.
Joined: Oct 2017 Posts: 1,504 Threads: 54
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Whilst a Lucas 30E vacuum wiper motor works reasonably well on a standard engine with a 22FZB, it's next to useless on a 26Va carburettor.
Joined: Aug 2017 Posts: 881 Threads: 48
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Location: North Wiltshire
Car type: 1927 Chummy, 1938 Big Seven 1/2 a Trials Chummy
My Chummy has a SU UBA carb (ex Morris 8) and a box saloon style wiper (Lucas 30G) and this works well. The manifold is made up from copper pipe with brass flanges and the take off is at one end of the manifold.
Joined: Aug 2017 Posts: 108 Threads: 5
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I'm sure I've got a body for an early-ish SU which has a takeoff on the side of the flange it's self, similar to the type seen on an early inlet manifold. I also have a later combined type manifold with a takeoff about 1-2 inches from the carb flange presumably for a vacuum wiper, I've blanked it off with a screw but it presumably was for a 26VA with vacuum wiper.
Joined: Aug 2017 Posts: 919 Threads: 18
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Location: North Yorkshire
My 1931 saloon has an SU with a Trico vacuum wiper motor. In general use turning on the wiper does nothing at all. However, when you get to the point that you can't see a thing, if you take your foot off the throttle for a split second the wiper will flick back and all is well. In my defence I would point out that on one of my Coast to Coast Runs, I was able to continue motoring when the modern cars had been forced to stop by the severity of the rain. It was during that run that I developed the technique of driving with a wash leather in my hand. There was so much water getting around the windscreen that every few hundred yards I was leathering the inside of the screen, opening the drivers door window, wringing out the leather, closing the window, repeat as necessary. The cubby holes either side of the dashboard fill with water and are remarkably watertight, when you turn left the water in the RHS one pours out onto your knee. Driving an Austin 7 in heavy rain is quite entertaining!
