Oil Pressure Cut-out Switch

[Geth]

Well I've had a busy (expesnive) shopping day today. One of my new purchases was a Facet Red Top Fuel Pump for the T40s. While reading the installation instructions it turns out I should see about getting an Oil Pressure Cut-out Switch. The reasons for fitting this switch are obvious but what I'm not sure about is how one would be fitted or even if one can be fitted. Has anybody else fitted one of these to a nova and is there anything I need to do or buy to fit it?

Cheers,
G

[Stuart]

not really needed imho. if your oil light comes on then id hope you'd turn off the engine anyway

[Geth]

I was thinking more along the lines of fitting one as a safety feature to stop the pump if the engine stopped in an accident or prevent flooding if I stalled in the engine.

[Adam]

The oil pump runs off the crank, so if the engine stalls the pump wont be running?

[Geth]

I'm well aware of that. But a Facet pump is an electric fuel pump for carbs. The purpose of the Oil Presure Cut-out Switch is to kill the power supply to the fuel pump when the Oil pump stops turning and the ignition is still on i.e. in an accident or when the engine stalls.

[Adam]

With a fuel pump relay etc the pump doesn't run when the engine is not running even with the ignition on.

Depends how your wiring the pump.

[Geth]

How would you wire it then? The instructiions say that you simply wire it up to the live so that when the ignition comes on the pumps starts.

[Adam]

Ye, thats the easiest way.
But your pump will be constantly running with ignition on.

You can wire it like GM, using a relay which gets switched.
BUT i think its the ecu that switches it, not much good on a carb(ecu-less) engine.

[Geth]

I had a funny feeling you were goingto say that. I don't like the sound having the pump running all the time so would really like to know how the cut-out switch is fitted.

[Adam]

I guess the cut out switch must supply the earth to the pump.
So when the circuit is made(engine cranking/running) the pump is earthed and runs.

When the circuit is broken(earth disconnected) the pump no longer has 12v across it and switches off.

[Geth]

I understand the concept of what it does, but where does it fit to the engine. The only place I can think of would be where the Oil pressure sender sits, but where would the oil pressure sender go?

[Welsh Dan]

One problem I can see with this, is that if the engine is off then the fuel pump will be too, so unless you fitted a button that would turn the pump on while the button was held down, you'd probably have trouble starting it.

I'd say it would be easier and more practical to wire the pump to ignition live then add a killswitch for it.

[Geth]

That's another thing I was thinking about. Unless turning the engine over on the starter motor creates enough oil pressure to turn the pump on.

TBH, I'm wondering if I might just forget about this cut-out switch idea. It seems it might be more trouble than it's worth. The car is mainly going to be used for track days anyway.

[Welsh Dan]

When we fitted a facet pump to my mates T40 astra all we did was wire it to ignition live and hide a switch under the dash.

[Geth]

Sounds like a plan to me mate. I fancy having a few more switches on the dash, maybe even with a red LED to tell me when it's on. Hmmm... S****y :D

[Geth]

Above word was S W A N K Y lol

[benthehash]

if you set it up with pressure cut out you would need an over ride button to start it. i'm gana have some buttons on the dash to relays. pump/constant fan/ ignition start. where did you fit your pump to? i just drilled holes undearneath and bolted to car, looks vunrable tho!

[Geth]

I haven't fitted mine yet. I'm waiting until I my dad finishes the welding on his mates car before I get mine in the garage.

As I'm stripping my car out for track days I'm going to be putting it in the boot. The plan is to drill a hole in the boot, fit a grommit and run a pipe through from the tank into the boot, then another pipe going through a anothe hole back on to the main fuel pipe. I was thinking about fitting an internal fuel pipe but don't think it's really worth the effort.

[aswrally]

I haven't fitted mine yet. I'm waiting until I my dad finishes the welding on his mates car before I get mine in the garage.

As I'm stripping my car out for track days I'm going to be putting it in the boot. The plan is to drill a hole in the boot, fit a grommit and run a pipe through from the tank into the boot, then another pipe going through a anothe hole back on to the main fuel pipe. I was thinking about fitting an internal fuel pipe but don't think it's really worth the effort.
a red top pump can be mounted in the engine bay pipe straight from tank to pump then to pressure regulator then to carbs
my red tops in the rally car are wired from a switched live through a heavy duty toggle switch (and led) ...they turn off automatically when you turn off the ignition or as i run 2 pumps (1 back up ) can be switched individually whilst running

[mikey14sr]

the oil pressure cut out switch is basicaly an extra oil pressure switch, it fits to the oil pump via a t-piece (so you can still use the origional for the dash). Ones I've seen in the demon tweeks catalogue have a momentary by-pass switch for starting up.

[benthehash]

i thought you would want the pump close to the tank don't know where i heard this. i.m tempted to move mine under the bonnet just befor pressure regulator do i need another fuel filter or is filter king fine?