You will need another sending unit for the red light, one from a '65 Mustang that had an oil pressure warning light instead of a gauge. The only problem with that is that the red light doesn't illuminate until the pressure has dropped to about 5 psi which may be too late.to prevent damage. Perhaps there is an aftermarket sending unit that closes the switch at about 20 psi which would give you a few seconds to react.

Was just talking to my buddy in Ohio about this.     He basically has said the same thing.    He does recall of a car back in the day that had a feature with the light and a gauge but couldn't recall the specifics of how it was setup.     He did say he's going to give it some thought and we also discussed being able to turn off the light at 20 psi.   I'm sure someone out there can figure that out but it's not me.  Lol

This may be what you're looking for. The description is not very informative.
https://www.amazon.com/Allstar-ALL99059-Pressure-Switch-Thread/dp/B006K8WG44

It is what you're looking for. A better decription.
https://allstarperformance.com/pressure-switch-20-psi-all99059/

Last edited by Texas! (10/14/2024 6:51 PM)

Texas! wrote:

This may be what you're looking for. The description is not very informative.
https://www.amazon.com/Allstar-ALL99059-Pressure-Switch-Thread/dp/B006K8WG44

It is what you're looking for. A better decription.
https://allstarperformance.com/pressure-switch-20-psi-all99059/

 
I just ordered that switch.   I really like the idea of a red light coming on if I drop below 20psi.   I'll place the red LED right in the center of the speedometer and Tachometer gauges.   

I also found this extension that has dual ports.   I ordered it as well.

BobE wrote:

FYI - the oil pressure port in the engine block is 1/4" NPT threads.  The switch is 1/8" NPT, that extension appears maybe to have both, and w/o the dual ports it looks very similar to the OEM extension Ford used for the oil pressure sensors. 

 
I was going to just drill and tap my current extension but saw this when I did a quick search.  Figured I would give this a try.  Worse case is I may have to put a small extension in the 1/8 port to raise the pressure switch up a little to clear the oil pressure switch.   The oil switch is pretty large in diameter.

I don't have the extension installed here but it's a tight fit.  The autometer oil sensor is pretty big.  I'll snap a picture of it tonight when I get home.  I have all the common NPT taps in my tool box.

BobE wrote:

Note that the 1/8" and 1/4" NPT are normal thread size used in the plumbing world.  Pipe nipples of various lengths, elbows, tees etc., are available at Home Depot, Lowes, Ace Hardware, etc. (but may not look as nice)
I wouldn't use a plastic line to feed the oil gauge. 1/8" copper tubing would be a better choice IMO.  (Especially that close to the exhaust header) 
Just saying. 

 
The plastic oil pressure line was only used for the test start I did on the engine cart.  It's not a permanent thing and has since been removed.   The autometer oil pressure gauge is electronic. 

I was already thinking I may have to raise the pressure switch I want to add up a little to get a better fit. Once it's painted black no one will ever notice I used plumbing pipe from HD.  Lol.

Rudi wrote:

Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

 
C'mon Paul Harvey, tell us the rest of the story.

Rudi - Wow, glad that trip ended safely for you. 

That sure would be something that would cause me to have a panic attack.  Rudi hiw old was that copper line

Yeah it was a major pucker episode, almost as bad as the 500 ‘  AGL  engine failure on take off a few hours after the first flight.
The copper line failure happened about a year after the first flight.
Less than 25 hours of flying time , new when installed. There were anti fatigue loops at each end as well.
The crack was right at the compression nut at the back of the gauge.

Last edited by Rudi (10/17/2024 3:11 PM)

Rudi wrote:

Copper line will work harden and crack if subjected to vibration.
I unfortunately found that out many years ago when the oil pressure gauge connection in my home built sprung a leak 3000’ over Chicago flying home from Oshkosh.

Years ago I was in a very old Cessna 310 in the front passenger seat flying over the Cascade mountain range - at night - in Washington when I felt something warm and wet on my left foot. The right hand engine oil pressure gauge was leaking oil down the back side of the instrument panel. Old style direct reading gauge with a copper tube going to the back side. Had some rags, so I wiped up what I could and put the rags on the top of my foot. We made it to Moses Lake in eastern Washington finally and landed. We checked the oil quantity and added a half quart, but we also found the exhaust stack for #4 cylinder had broken off. The owner called his partner to fly us in another stack from Seattle. It was about 2:30 am when he landed with the part and the owner's mechanic. I had accompanied the owner to change out a magneto on a Beech Queen Air so it could be repossessed, but that job went to Hell. I told the owner that I was done and hitched a ride back to Seattle on his partner's 182. General Aviation..................
 

The extension arrived today so I had to install it.  The extension is a little longer than the one I had on there.  I had to remove the hydro boost return line from the back of the pump in order to thread the oil pressure gauge in.   Tight fit but both the switch and gauge are in.