Oil pressure dropped to -zero- today...

[jrevens]

Lowell,

I really like your idea for an oil pressure "idiot light". Could you tell me at what pressure your switch closes? Also manufacturer & part #, if possible.

Thank you!

[GWright6970]

Lowell, I hope you don't mind me posting another picture of your excellent installation! This one shows the sensors install in relation to the whole engine install.

I will most certainly be following Lowell's lead when I install my 912UL this winter. I am amazed a wee bit, that certified aircraft are not required to have this... it simply makes sense.

Thanks again Lowell, for allowing me to photograph every inch of your great bird!

[HighWing]

The switch is from Summit Racing - http://www.summitracing.com/parts/mrg-7872/overview/
They are designed to cut power to electric fuel pumps with the engine oil pressure drops. The reason for the three connectors is to allow the pump to be connected to power through the starter solenoid so it will operate with low oil pressure during the initial cranking.

I found wiring to be a bit tricky as our application is quite different than what it is designed for. The fuel pump terminal goes to battery +. The starter solenoid terminal goes to the Red LED. The battery terminal goes to green. I think. You could wire it as above and then use compressed air to check that the wiring works. The LEDS required a resister to bring the 12V down appropriately.

I used a flasing red LED for the warning light. The following link is to Mouser where I got the mounting harnesses. http://www.mouser.com/catalogviewer.aspx?page=177&highlight=593-CNXCE4108&catalogculture=en-US&catalog=646
The Red LED diameter is 5mm. The green LED is 3mm. If you go to the VCC mounting, you will need the socket and the appropriately colored lens. When everything is positioned and works satisfactorily, it is a good idea to pull the socked away from the lens and drop a bit if instant glue between them to keep everything together. I have found that sometimes the green harness can pull away from the lens. When it falls away, there is no green power light visible. It is on, but floating somewhere behind the panel.
Lowell

[Dorsal]

Well I am thinking it is time to address this issue on my setup. Recently when I flip on the master switch the oil pressure will read > 15 psi (yesterday morning 40) without the engine running. As I had the cowl off I tapped the sensor with a screwdriver and the reading went to zero. Sounds like a sensor on the way out, plan to replace it (and fuel pressure) with the Kavlico units mounted on the firewall. Van's makes a nice little manifold for this that I saw on my friends Velocity. The unit has room for three independent ports so if I link two I get fuel, oil pressure and a back-up switch as Lowell suggests.

[Dorsal]

Flying back from Acadia yesterday and the oil pressure started to dance more than the usual +-5 and occasionally into the red on the high side . Just when I thought it best to land it would drop back to 60 and behave for a while. Was fairly confident it was the sensor and was almost home. Changed over to the Kavlico sensors with a redundant 15 PSI NC switch for an idiot light. The manifold is a stock item from Van's. Did not get a chance to fly today but on run-up things were clearly more stable and my fuel pressure read over 3 for the first time ever (steady at 4 psi).