Ron,
If adding an electric pump to a car that didn't have one originally, the
below information is spot-on:
"Getting power to the pump involves adding a safety oil pressure switch so
the pump only runs when the ignition is on and the oil pressure is up. This
is done by installing an oil pressure switch from a Chev Vega (you may also
need a couple of 1/8" pipe tees and short nipples if you also have an oil
pressure gauge). These switches are available from most local auto parts
stores. Three part numbers: NAPA (Echlin brand) p/n OP-6610 or Standard
brand p/n PS-133 or Delco PS-9. While at the parts store, also get a
standard sealed-beam headlight 3-prong socket connector. This connector fits
the new oil pressure safety switch.
The switch has three prongs marked "I", "S" and "P." When there is NO oil
pressure, the "S" and "P" are connected. When there is oil pressure, the "I"
and "P" are connected.
The "I" wire is connected to the 12 volt side of the Ignition dropping
resistor. The "P" wire goes up to the pump. Only one wire need be run from
the back to the front. It is also a good idea to put a 5 amp fuse in this
line. The "S" wire goes to the starter solenoid "S" terminal to energize the
pump during cranking. The negative terminal of the pump is grounded to the
pick-up tube with a clamp. (see Fig. A side view).
How does it work?
In the gauge installation, a wire runs from the pick-up terminal of the
starter solenoid which is energized only when the key is turned to start the
motor. The current goes through the normally closed (at rest) contacts of
the oil pressure switch to the fuel pump (between contact "S" and contact
"P"). When the engine starts and the oil pressure rises, the switch
transfers, causing current flow from the ignition switch (contact "I")
through the transferred switch contacts to the fuel pump (contact "P"). As
long as oil pressure is maintained and the ignition is on, the pump keeps
running. This is also an engine protection feature, if oil pressure is lost
from an oil pump failure, the engine automatically shuts down."
I would add one other thing - its better to have the power "P" wire from
above listed switch trigger a relay that feeds the pump instead of powering
direct. Some pumps can draw some serious amps. Both my cars are wired this
way.
Mark Sedlack
New Franklin, OH
66 1600 http://www.mildevco.net/chevypowereddatsuns/
77 280Z http://www.mildevco.net/chevypowereddatsuns/
----- Original Message -----
From: "Ronnie Day" <ronnie.day@gmail.com>
To: "Roadster List" <datsun-roadsters@autox.team.net>; "510 List"
<bluebird510@googlegroups.com>
Sent: Wednesday, July 31, 2013 10:41 AM
Subject: [Roadsters] Electric Fuel Pump
> Anyone have a specific suggestion for an electric fuel pump for the ('70
> 2000/SU) Roadster. Yes, I know I can go with an OE unit, but they run
> around $150 so I'm considering using an electric. I know it needs to be
> around 3 psi.
>
> Most of the ones I see with a quick search are high pressure unit for use
> with newer EFI systems. I seem to rememember Holley and S-W having
> suitable
> models. I'll need a pressure switch, too, for the power if I go this
> route.
>
> TIA,
> Ron
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