oil pressure switch

[jbagley]

Looking to install a Hobbs meter and a low oil pressure warning light in my panel. I don't know that these things could use the same oil pressure switch, but Van's thinks that a 15 psi switch is about right for both applications.

I'm kindof a noob when it comes to Lycoming's. But, that seems a bit *too* low oil pressure to me to serve as a useful warning. Does anyone know what the normal operating range of oil pressure for an O320 is?

Thanks!

[Lars]

Low oil pressure on a Lycoming is around 20 psi. 15 psi is high enough that your engine won't die but low enough that you should be worried. The switch Vans sells is a single pole double throw (SPDT) switch, so it can both run the hobbs meter and turn on an idiot light.

[gasman]

I would use it for the hobbs and master warning, but not oil pressure. If you want a warning light for oil pressure I would use one that let me know that the pressure has dropped to 50 psi.

You might want to look at NAPA part #701-1607 It is a hobbs switch that starts the hobbs meter above 60 psi. But will turn on the warning light at about 60 psi.

On Vans oil pressure gauge, the yellow is from 25 to 55 psi. normal is 70 to 80 psi.

[Bad Sheila]

Normal is 55 to 95 psi. I had only 51 psi which was way too low. I bought the Lycoming "adjustable" oil pressure relief valve and using the correct spring, set it to 75 psi.

Minimum according to Lycoming is a lot more than 15 PSI. I can get this for you tomorrow when I go to my hangar.

I can also get the part # for the adjustable relief valve also if you want.

Tony