Inertia Switch or Oil Pressure Loss Shut Off Switch to Fuel Pump

[Ol'Blue]

I went with the Ron Francis inertia and finally got it installed and it was super easy. Hooked it up, slapped pretty hard and it triggered shutting off the pump. Hopefully its not too sensitive for off road. Will find out soon.

https://www.ronfrancis.com/product/90

Thanks for the help. I feel a little safer with this puppy installed.

 

[Steve83]

Wow... $190

$81 inertia switch https://www.amazon.com/dp/B000NU76RM/?tag=classicbroncos-20
$13 pigtail https://www.amazon.com/dp/B001RPYY9A/?tag=classicbroncos-20
$2.50 fused relay & socket https://www.amazon.com/dp/B07PK7F1MC/?tag=classicbroncos-20

So that's ~$93 for the 2 crimped-on terminals.

Unless it's not a genuine Ford inertia switch...
$42 copy inertia sw. https://www.amazon.com/dp/B07F838BFP/?tag=classicbroncos-20

 

[nvrstuk]

For those following this thread with high pressure pumps running high hp, remember to check the amperage draw of whatever pump you're running. Obviously for a qjet (unless it's plural) high amperage shouldn't be an issue but my pump draws 28 amps and I would not run that much amperage thru the inertia switch w/o a relay.

 

[Wild horse 75]

For those following this thread with high pressure pumps running high hp, remember to check the amperage draw of whatever pump you're running. Obviously for a qjet (unless it's plural) high amperage shouldn't be an issue but my pump draws 28 amps and I would not run that much amperage thru the inertia switch w/o a relay.

As a rule of thumb unless you’re running a small frame mounted fuel pump designed to replace a mechanical pump you should always use a relay. I don’t know why people are scared of wiring in a relay, it’s not that hard. Then you can install an inertia switch on the ground side of the relay and have that protection. And for people out there who like redundancies you could have another relay plug beside it and wire that without the inertia switch and have a fail safe should something to wrong with the wiring in the other one.

 

[ssray]

Maybe a good thread for this question I’ve pondered before. Dealing with the actual loss of oil pressure. I know of dry sump oil systems though admit I’ve never taken time to dig into the details. But has anyone seen an implementation of an electric pump with the intake plumbed into the front of the oil pan and outlet into the oil galley. Would need a check valve or pump that wouldn’t back feed into the crankcase when not in use. Likely could get by with less output than the main pump, but enough for low rpm on steep downs or idling if you got hung up nose down and needed to winch or help backing up with someone winching from behind or those few that have rear winches. Maybe rarely needed but would be nice if it could be done inexpensively as it wouldn’t be used often. Thoughts?

 

[Wild horse 75]

My experience with electric pumps pumping oil is that they fail quite frequently. We had a twin turbo C3 corvette and the turbos were mounted too low to have gravity return the oil to the pan so they had little electric pumps to return the oil to the pan. They failed all the time and would cause the turbos to burn up the bearings. So this is on a no pressure return line. I’d hate to imagine a high pressure one trying to feed your engine. With you’re worried about off camber situations get a baffled pan. If you’re worried about initial startup get a primer tank. Dry sump systems are very different. They use a mechanical belt driven (usually) pump run off the crankshaft and use a large external holding tank. Pressure lines are then plumbed into several different places on the engine to feed oil. Then the pan serves only to catch drain back and the pump pumps it back to the tank to start the cycle over again.

 

[Steve83]

Dealing with the actual loss of oil pressure. ... Maybe rarely needed but would be nice if it could be done inexpensively as it wouldn’t be used often. Thoughts?

The easiest, most-effective way to avoid that (and nearly ALL oil starvation concerns, including startup) is a simple oil accumulator with a simple 12V valve plumbed in where the pressure switch/sender goes, or via an oil filter adapter plate (which makes filter relocation attractive). When the key is in RUN (at startup, or while the engine is running), the valve is open/ON/powered (NOT using any pressure switch). If there's less pressure in the engine (during cranking or during an oil starvation event), the accumulator spring pushes oil out to the engine, just like the pump normally does. If there's more pressure in the engine than the accumulator (when the engine is running normally), the pump pushes oil in. When you turn the key off, the valve closes before the accumulator can empty, so it's ready for the next startup. It's virtually foolproof, virtually failsafe, and virtually eliminates engine wear due to low oil pressure.

https://www.amazon.com/dp/B000CONY9I/?tag=classicbroncos-20

https://www.amazon.com/dp/B004U3XI7U/?tag=classicbroncos-20

 

[ssray]

Thanks guys…good suggestions and ideas! Even keeping it simple gets costly but when it comes to lubrication you need reliable components. Would be tempting to use the accumulator with a cable operated valve…just pull the knob when you shut it off. Great use for those old style Bronco controls. And throwing turbochargers into the mix complicates it even more as they don’t like to be starved, particularly under load. Makes you wonder how the new crop of turbocharged engines handle extreme angles. At least low engine rpm descents would be like a normal key off shutdown.