Electric Fuel Pump & OP Safety Installation

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TORQUER
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Re: Electric Fuel Pump & OP Safety Installation

Post by TORQUER »

azdave wrote:Inertia (crash) switches are another good safety device when using electric fuel pumps. I find them on ebay.
Ive seen alot of Ford vehicles with these switches located in the trunk or on the firewall. You should be able to find one easily in a junkyard for next to nothing. My 86 F150 has one on the right side of the transmission tunnel up under the dash. And a friends early 90's thunderbird had one in the trunk. They are easily resetable, just push a button.
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Scott V
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Re: Electric Fuel Pump & OP Safety Installation

Post by Scott V »

azdave wrote:Inertia (crash) switches are another good safety device when using electric fuel pumps. I find them on ebay.
its a good idea & safety devices are always nice to have......but is a interia switch really needed on a non efi car? i think if the car is hit hard enough to trip the inertia switch the engine is going to stall cuz the carb will misbehave. if by chance - the inertia switch trips & the engine keeps on running the engine will still run until the bowls are empty. i guess thats better than haveing the engine run when you are on fire. gg if the crash breaks a fuel line & the engine keeps on running - then haveing a inertia switch could be a good thing.

i remember hearing some cars would trip the inertia switch when they hit a big bump or pot hole. it would be a good idea to mount the switch somewhere you its ez to get to if you have to reset it.

-Scott V.

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Re: Electric Fuel Pump & OP Safety Installation

Post by TORQUER »

Inertia switches are used to cutoff the high pressure fuel pumps in the event of a crash. You can use this on a carbed vehicle that has an electric fuel pump installed.
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azdave
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Re: Electric Fuel Pump & OP Safety Installation

Post by azdave »

Scott V wrote: ... is an interia switch really needed on a non efi car?-Scott V.
Needed? No. A great safety device? Yes!

An inertia switch is not there to kill the engine. It's there to stop the fuel delivery after a hard crash. In a crash (even if the engine dies immediately for other reasons) do you want the fuel pump to continue pushing fuel through a ruptured fuel line while you are possibly trapped or unconscious inside the vehicle?
Dave W. from Gilbert, AZ
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MonzaDave
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Re: Electric Fuel Pump & OP Safety Installation

Post by MonzaDave »

There is also an rpm sensing safety switch that cuts off the fuel pump when rpms go to zero. It has a 3 second delay in the cutoff when the ignition is first turned on. It's sold by American Pi (Ray Sedman).
Dave Keillor
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Re: Electric Fuel Pump & OP Safety Installation

Post by TORQUER »

Well, Dad still hasn't picked up this corvair, but I will be traveling to KY friday and will be going to get it with him saturday. I won't be able to work on it anytime soon because I live in Tulsa. I am moving back to KY in a year or so, so I will work on it then. Until that time, I think I want to work on planning a Subaru turbo setup for it. Smoother running, better sounding, better mileage, liquid cooled.
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azdave
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Re: Electric Fuel Pump & OP Safety Installation

Post by azdave »

MonzaDave wrote:There is also an rpm sensing safety switch that cuts off the fuel pump when rpms go to zero. It has a 3 second delay in the cutoff when the ignition is first turned on. It's sold by American Pi (Ray Sedman).
In a crash, if the engine doesn't die from the collision then the fuel never gets cut off? Seems not as good as an inertia switch for crash safety but still better than nothing.
Dave W. from Gilbert, AZ
65 Corsa 140/4
66 Corsa 140/4
66 Corsa 140/4 w/factory A/C
66 Corsa 455 Toro V8
65 Monza Convertible 110/4
66 Monza Convertible 140/4
65 Monza 4DR 140/PG w/factory A/C
65 Monza 4DR EJ20T/5

ron l
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Re: Electric Fuel Pump & OP Safety Installation

Post by ron l »

The RPM sensing switch is an alternative to the oil pressure switch; with either one an inertia switch would still be a wise suggestion. The switch is likely a Bosch fuel pump relay as seen in VWs and Porsches. Wired like a normal relay but with an extra terminal to plug a tach signal into.
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MonzaDave
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Re: Electric Fuel Pump & OP Safety Installation

Post by MonzaDave »

azdave wrote:In a crash, if the engine doesn't die from the collision then the fuel never gets cut off? Seems not as good as an inertia switch for crash safety but still better than nothing.
So, how is that any different than having a mechanical fuel pump? There is no cutoff mechanism in a stock Corvair if you're in a crash and the engine keeps running. The inertia switch is sensitive to mounting and location. Plus, I've seen too many false triggers in the Ford sensors. I don't want my engine to die because I hit a pothole.
Dave Keillor
Rochester, MN

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azdave
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Re: Electric Fuel Pump & OP Safety Installation

Post by azdave »

MonzaDave wrote:
So, how is that any different than having a mechanical fuel pump? There is no cutoff mechanism in a stock Corvair if you're in a crash and the engine keeps running.
It's minor but there is a difference in the safety factor. In a Corvair with a standard fuel pump the fuel is only pressurized in the last few feet of fuel line between the fuel pump and the carbs so no fuel would spray out unless damage was in that small zone. With an electric fuel pump (ideally mounted near the tank) you now have many more feet of pressurized fuel line exposed to damage in a crash and more likely to be spewing fuel while the engine runs.

Keep in mind that more modern cars often have 40-70 PSI in those long fuel lines from the tank to the engine. Any leak in those is much more serious than at 3-4 PSI in a Corvair. Inertia switches are much more important for safety in those high pressure systems.

The inertia switch is sensitive to mounting and location. Plus, I've seen too many false triggers in the Ford sensors. I don't want my engine to die because I hit a pothole.
I've never false triggered an inertia switch so that's not an issue in my experience.

Everyone should follow whatever safety procedures they feel comfortable installing. In every Corvair I have ever purchased (those with an electric pump already installed) the pump was wired to run in both the "accessory" position as well as "run" postion. That is one of the basic things to avoid in my rule book. Additional safety steps are up to each owner.
Dave W. from Gilbert, AZ
65 Corsa 140/4
66 Corsa 140/4
66 Corsa 140/4 w/factory A/C
66 Corsa 455 Toro V8
65 Monza Convertible 110/4
66 Monza Convertible 140/4
65 Monza 4DR 140/PG w/factory A/C
65 Monza 4DR EJ20T/5

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BrooklynCorvair
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Re: Electric Fuel Pump & OP Safety Installation

Post by BrooklynCorvair »

Just to update you all, I've successfully installed the electric pump. Next in line is replacing the carbs with a pair of rebuilt performance carbs I purchased from Grant Wolf.
azdave wrote:Everyone should follow whatever safety procedures they feel comfortable installing.
I ended up going with the good ole reliable A.L.I.D.H. Safety Switch (At Least I'll Die Happy). :cool:

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