Low oil pres engine kill switch

[LolaT440]

Does anyone wire in a oil pressure kill switch?

If you lost pressure, you would not need to worry about missing the warning guage. When you start I assume the car would not fire until you cranked it enough for pressure. Or maybe you would need some type of switch to turn it on.

[TimW]

I use the 3 pole pressure switch from Pegasus (#1109) in series with my electric fuel pump. The 3rd pole is energized by the starter solenoid signal to close it when starting. But, I've also wired it so that I can optionally bypass this switch and run the pump directly in case the switch fails.

[Mark H]

To risky if you have a low oil pressure blip, oh no why did my ingition cut out?
If it worked everyone would use it?

[Dave Belz]

I know that if I'd had one in my FV, I'd have pushed it back to my paddock space every time I left the track at Road America...

Dave

[JHaydon]

One point to remember about this switch: it's a fuel pump shutoff switch, not an ignition kill switch. If you're running a mechanical fuel pump, it won't do anything.

That said, it has a bypass circuit as Tim alluded to, so that the pump will run while you crank the engine.

I don't recall offhand what the cutoff pressure is, but I think it was down around 10psi or less -- less than you'd want to see at idle.

[Steve Demeter]

I have a Longacre switch. think it cuts off at 10 psi or something pretty low. I also have a bypass toggle switch wired in also for starting and idling back to the paddock.

It has saved me one blown up motor when I threw an oil pump belt off and it shut the engine down.

Never had it blip during a session.

[LolaT440]

I have a FF with mechanical. There must be some way to kill the ignition of such a switch? Have the coil power through switch

[TimW]

[size=1]I don't see why this same switch can't be in series with the ignition switch to the HT of the coil instead of the fuel pump power. I would think that the draw of the HT post of the coil would be less than the electric motor of the fuel pump. You would definitely need the bypass pole energized though in this scenario; though if you don't want to start the car until some pressure is built then perhaps not using it can acheive that. I don't use it on my car, as the bowl is full enough to get the engine started and the pump can 'catch up' the bowl once oil pressure rises in a second or so.[/size]

I would only confirm that the switch can carry the amperage required of the HT post on the coil. If the cutt off switch has a higher rating than your ignition switch you should be good. But also be aware that if this switch fails it will end your session. Its probably more likely to fail than an aircraft grade SPST ignition switch.

[JHaydon]

The fuel pumps we carry (Facet and Holley) are all in the 2 amp range.

Does the coil get fed more than 2 amps? If not, you should be okay. If it's much more that that -- or if you run an MSD -- then look into an ignition relay controlled by this switch.

(Tim, you mean LT, don't you? The small wire going to the + on the coil from the ignition switch, not the big wire at the center tower of the coil.)

[TimW]

[size=1][/size][size=1]Yes, the + side of the low power post on the coil. Sorry.[/size]

[Ray Grienke]

The way to determine the coil current is to measure the resistance of the coil - across the two small terminals. Then divide the battery voltage (use 12.6v) by the reistance. Result of that is the coil current. If I remember correctly, the coil resistance is about 1.7 to 2.0 ohms, resulting in a coil current from 6.3 to 7.4 amps.

Please check your own coil and don't trust my memory...