engine safety switch

[Ted Brown]

A very good/handy safety switch...
Well it came to me that with so many fellows using belly pans on their rides these days, that this idea, taken from ski boaters, would be a great idea for most any Hotrod...
When they want to drain their oil, they have a long direct oil line into/from their main oil pressure system with a shut off valve at the end of that line, which they put into a container, that will hold all their old used oil... With the line valve turned on and fixed into that container, they now start their engine, as soon as the oil pressure falls off, the engine automatically shuts off, no oil pressure, no run...
Nice clean easy way to change the oil... They also have remotely located oil filters for easy access to make changing a snap... No under the engine or car to change oil ever again

I think a good quality in-line brake light switch would/should work well for this, ya think??
For engines that use a 12 volt start wire, and a wire from the Ignition, switch = 6volt from the resistor run wire, it would take two pressure switches in the main oil pressure line to make this a nice safety start and shutoff switch...

I know that when starting a supercharged engine, one cranks the engine till they get oil pressure and then hit the mag switch to light the engine, again, no oil pressure, no start... as that can hammer the bearings out of the engine when that engine lights and hits that crankshaft with plenty of downward pressure...

I also have known a few people that had their oil changed by a quick oil change place, and the service people/person did not either tighten the oil pan plug, and/or stripped it out, or failed to tighten the filter correctly and while driving the car owner did not notice the oil pressure light or gauge, which ever, because the engine lost all it's oil, then broke or messed up their engine without knowing why...

Now, if they would have had a safety switch in their system, that could not happen, the engine would have just shut off before hurting anything...

I am going to have this setup in my new car for sure, and I will also install one in my now T Bucket, very cheap insurance!
As it is just to easy to miss looking at your oil gauge in time to save your engine from any damage, because when you hear that bearing, it is now usually too late... I would think
SO; My friends, drive with peace of mind, knowing that your engine is a lot more protected now... What do you think?? Drive safe!

 

[ellis8500]

You can buy an oil pressure activated safety switch. Connects to the start circuit and ignition so engine will start with no oil pressure and only run when there is pressure. These are usually used in the electric fuel pump circuit but would also work in the distributor circuit. I believe Summit, Speedway, Jegs and others sell them.

 

[409T]

You can buy an oil pressure activated safety switch. Connects to the start circuit and ignition so engine will start with no oil pressure and only run when there is pressure. These are usually used in the electric fuel pump circuit but would also work in the distributor circuit. I believe Summit, Speedway, Jegs and others sell them.

If you put this in the distributor circuit, will the engine build up enough oil pressure to open the switch while just cranking?

 

[Ted Brown]

If you put this in the distributor circuit, will the engine build up enough oil pressure to open the switch while just cranking?

Yes it will, we always did this with the drag cars without (crank till oil pressure showed on gauge)a real safety switch... I like the idea of not starting till oil pressure is at least 3 lbs. which is no trouble to get cranking right off... I will have to check which type of switch works great and the cost of both types... I do not like to spend more than needed... to get the job done, plus I myself will use a ground operated relay, to lessen any power loss at/through the pressure switch.
Brake light switches are easy to find and not expensive... use the type with a screw type connection, sure do not want the wire falling off...

 

[RPM]

The old Vegas and Monzas had this switch and it works really well.

 

[ellis8500]

Holley 12-810 - Holley Safety Fuel Pressure Switches

Here is one fuel pump safety switch designed for that purpose.

 

[Screaming Metal]

Holley 12-810 - Holley Safety Fuel Pressure Switches

Here is one fuel pump safety switch designed for that purpose.

Yes, thats the one I use for all my stuff, too.
And Rons right, back in the old days we wired those into the line with the electric fuelpumps. I also mounted a remote starter button and a remote kill under the hood for working on things also. The remote start was tied into a neutral safety switch.....

 

[Ted Brown]

I THINK YOU MISSED THE WHOLE POINT TO THIS SWITCH... I SURE WANT THE FUEL PUMP TO RUN BEFORE I START MY ENGINE, ONE WOULD BE IN TROUBLE IF YOU RAN OUT OF GAS, HOW WOULD YOU FILL THE LINE AND CARB?? A SWITCH TO SHUT IT OFF IS FINE... I JUST DO NOT WANT THE ENGINE RUNNING WITHOUT OIL PRESSURE FIRST, SAME FOR FUEL, THEY ARE BOTH NEEDED (FIRST) TO RUN... AND A BREAK LIGHT SWITCH WORKS WITH LESS PRESSURE, AND PROBABLY COSTS LESS ALSO...

 

[Hotrod46]

I have always wired electric fuel pumps with an oil pressure safety switch.

As far as the "no fuel on start-up" thing goes, I add a normally open, spring loaded toggle or pushbutton switch in parallel with the safety switch. That way I can prime the carb before starting. Comes in handy if your car sits for long periods too. It's surprising how fast the new formulations of that stuff they sell for gas now will evaporate.

If you have one of the older starters that has the extra stud for point ignition systems, you can use that to power the fuel pump during cranking and let the oil pressure switch take over after the engine starts. I prefer the priming switch myself.

I also have started using the Ford impact shut-off switches in my new builds. I've never had one "trip" by accident, but having the pump shut-off if you get hit in a wreck sounds like a good idea. A broken fuel line could pump out a lot of gas on a hot engine or exhaust before it could be turned off.

Mike

 

[Screaming Metal]

Hey Ted, I'm gonna try it and if it works and is cheaper....I'll switch. Brake switches are alot more durable in the long run.....

 

[fordsbyjay]

The old Vegas and Monzas had this switch and it works really well.

Until you changed the oil in them and they couldn't spin fast enough to prime the filter. Then you have a dead donkey on your doorstep. I don't know how many of them we "pushed" out of our quick change lube shop in the 90's after we could not get them running.

 

[Ted Brown]

Until you changed the oil in them and they couldn't spin fast enough to prime the filter. Then you have a dead donkey on your doorstep. I don't know how many of them we "pushed" out of our quick change lube shop in the 90's after we could not get them running.

ANYONE THAT CHANGES OIL AND FILTER AND DOES NOT FILL UP THE NEW FILTER COMPLETELY, I DO NOT KNOW WHY THEY ARE DOING THIS FOR OTHERS, AND FOR MONEY AT THAT... DAAA

 

[RPM]

Until you changed the oil in them and they couldn't spin fast enough to prime the filter. Then you have a dead donkey on your doorstep. I don't know how many of them we "pushed" out of our quick change lube shop in the 90's after we could not get them running.

I didn't know Vegas and Monzas were still around in the 90s. You don't see those cars any more at all. The little Monza 2+2 was a fun car. I had one with the old LT1 in it, with n2o, drove it to work everyday.

 

[putz]

I didn't know Vegas and Monzas were still around in the 90s. You don't see those cars any more at all. The little Monza 2+2 was a fun car. I had one with the old LT1 in it, with n2o, drove it to work everyday.

I saw a chevy luv truck the other day about the same vintage.

 

[fordsbyjay]

ANYONE THAT CHANGES OIL AND FILTER AND DOES NOT FILL UP THE NEW FILTER COMPLETELY, I DO NOT KNOW WHY THEY ARE DOING THIS FOR OTHERS, AND FOR MONEY AT THAT... DAAA

We always filled the filter but you would get the odd beater that would just not start after an oil change. I don't know if they were just so wore out but they couldn't build enough oil pressure simply by turning the engine over.

 

[Screaming Metal]

I didn't know Vegas and Monzas were still around in the 90s. You don't see those cars any more at all. The little Monza 2+2 was a fun car. I had one with the old LT1 in it, with n2o, drove it to work everyday.

Monza + LT1 + the Bottle = A really big smile!!!! I thought we were having fun when we were shoehorning the aluminum rats into the Vegas! Ha!

 

[fordsbyjay]

I didn't know Vegas and Monzas were still around in the 90s. You don't see those cars any more at all. The little Monza 2+2 was a fun car. I had one with the old LT1 in it, with n2o, drove it to work everyday.

Just like Pintos there were lots of them in the 80's and 90's. Now you don't even see them in junk yard anymore.

 

[rooster57]

Their is a local guy who comes to some of our events who has a cosworth vega. Its still cool

 

[Wild Mango]

Their is a local guy who comes to some of our events who has a cosworth vega. Its still cool

In the Midgets we always used an oil pressure switch with NC contacts across the kill switch to short the Magneto primary so a loss of oil pressure shut the engine down. For some inexplicable reason it was called a Kaiser Valve.
I like to wire a NO switch like this into a changeover relay which switches the ignition as well as the fuel pump with a PB over ride for startup, and also breaks the starter solenoid circuit when there is oil pressure. This covers both eventualities, and incidentally makes it hard to hot wire on the part of joyriders.