Oil pressure sender/cutoff switch

[BruteForce]

I have a '72 Challenger with a 340. I plan to put in an oil pressure sender for the gauge and a cutoff switch for the electric fuel pump. As you can see in the picture, this plumbing rig is ripe for leaking.

Any better ideas?

[Chryco Psycho]

why not wire it into the Ign ECU instead
 the factory used this set up in later years to run both  light & guage , use soem teflon tape & it will stay sealed

[BruteForce]

I'm not sure what you mean. I need an oil pressure switch to shut off the fuel pump for safety reasons (having the idiot light hookup for it is just an added bonus). The ECU doesn't have an oil pressure connection? I'm using an MSD box, not the Chrysler ECU anyway.

I plan on using teflon tape, but this "christmas tree" just doesn't look like a great idea in a high vibration environment, I suspect it will also be susceptible to cracking.

[Chryco Psycho]

What I was suggesting is if the engine loses oil pressure why not kill the ign to prevent engine damage , it will take 30 seconds or so for the carb to run out of fuel once the oil pressure is lost
 the small red wire to the MSD can be run through the oil pressure cut off as well as the fuel pump wire

[BruteForce]

Ok, I see what you mean. Does anyone do this?

The idea with shutting off the fuel is not so much to save the engine, but in the case of an accident not having the fuel all pumped out of whatever severed fuel lines.

[Chryco Psycho]

I have hooked up both the Ign & Fuel pump this way in the past

[73EStroker]

Believe it or not ............. but vibration may snap that heavy weight off using that small 1/8 NPT thread as an anchor. For aircraft applications we use a HP hose fitting in the block, a flexible high pressure braided line over to the equipment which would be hard mounted to the firewall. Remember we have to do it right on planes....... we can't stop and walk can we?

[BruteForce]

Yeah, that's what I thought. But finding the bits to make this work seems to be a bit of a challenge. For example, the sender and the switch both have no mount points other than the pipe thread. So I need a female manifold I can bolt to the firewall to screw the sender and switch in. I've scoured my summit catalog with no joy.

I can't believe I'm the only one with this problem - with all the electric fuel systems out there!

[Chryco Psycho]

the Dodge trucks used that fitting for years set up the same way , I have never seen a broken one unkess some one put pressure on it

[BruteForce]

Ok, I guess I'll give this rig a try! Thanks for your help.

[Chryco Psycho]

the next best suggestion is the use some compression fittings & run a high quality hose to a remote location & put a tee there

[BruteForce]

I'm reluctant to do that because it'll be many more joints and potential leaks. I'll try this one first, if it fails, I'll try the hose idea.

[moper]

Later 70s and 80s V8s and trucks used that exact setup. There should not be that much vibration there. Just leave some slack on the wire leads so it can move with the engine. I wouldnt worry about running it.

[shadango]

Not the same situation, but I used a brass "t" fitting from the hardware store, after seeing another owner here doing that with the stock oil pressure switch and the fitting for a mechanical gauge....seems like it will work for me.  Ran the car for a few minutes and it seems to work.....

Ifnothing else it will be less tall than what you have going....?

[BruteForce]

There is one more thing that can help. The oil pressure sender (the big cylinder in the picture) is rather large. I bought it new from Rockauto.com. Does anyone know of a small one that has the same electrical characteristics as the original?

I see much smaller ones on ebay for other cars, but there's no clue in the specs what the resistance curve of them or the 340 engine one are.