"Adin, David" wrote:
>
> Ok guys . . .
>
> My neighbor (AC's and a TC - the Ferrari sits outside!) can't understand the
> talk of leaking SU pumps - were the older pumps brass where a tiger pump is
> "plastic" ???
>
>
> thanks for any forthcoming tutorials.
>
> D. E. Adin, Photographer
(Slightly snipped)
David,
Please do NOT be confused by misinformation on the list. The SU fuel
pump is NOT gasoline sealed by a plastic cap with a single nut. This
plastic cap is the cover to the electrical switching system points, and
allows energization of the solenoid coil. The coil (encased in the long
body) surrounds a central operating push rod (armature) that is
connected to a multi-layered, and pump diaphragm at the bottom (other
end) of the pump, near the aluminum bottom housing. The electrical
points activate the armature when low pressure is detected on the
output, and operates the diaphragm to pump fuel through inlet and outlet
gasoline valves in pressed steel cages.
The incident of cracking the electrical points cover, with the wire
input screw retaining nut, is completely separate from causing a leak.
This cannot be the cause. This is NOT to say that the unit wasn't
originally defective, or that it did not leak gasoline from some OTHER cause.
The SU pump is a sturdy and reliable design, when properly mounted and
the correct, original design, gasoline line connections are used. This
diaphragm pump is no different than the mechanical ones operated by a
camshaft on many of our carburetted American cars, before fuel
injection. The only instance of unreliability I have run into is the
tendency of the electrical points to get dirty, and not operate
properly. Maintenance cleaning is suggested.
The entire design of this pump, as well as description of operation,
setting, and maintenance, is located in The Rootes Tiger Workshop
Manual, Section C, (Fuel System), pages 4 through 7 in my version.
I am sure there are other quality electric pumps on the market that may
have some modern rotary pump designs, but be wary of the pressure
output, which can override your carb inlet valve. These carbs are low
pressure devices, but very heavy engine mods may require a higher flow
rate pump than stock,
Steve
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