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Today I confirmed with a mechanical oil pressure gauge that both when cranking the engine and running the engine on the ground that my oil pressure is steady around 70-75psi cold. I have not yet run the engine long enough for the oil to warm up (and don't plan to before first flight/engine break-in.) Other posts here seem to indicate that typical oil pressure is around 40-45psi, I'm wondering how others' experiences have been.

I believe that the Sonex supplied/purchased oil pressure gauge only reads up to 80psi, meaning that if the pressure gets much higher I might not even get an accurate indication. Should I not worry about this before running the engine to full operating temperature to see what the pressure settles at? Is it possible that one of my oil pressure relief valves (which I installed during engine assembly) is sticking? Any suggested troubleshooting, or should I leave it be?

Your pressure seems like what I see around idle after engine start. I wait until my oil temperature is > 100F to apply takeoff power. When I apply takeoff power, the pressure goes to ~60psi and settles around 45-50psi within about 8 minutes.

I can't remember the exact aeroinjector tuning procedure, but I'm pretty sure you will get the oil warm before tuning at wide open throttle.

I'd say you're close to where you need your pressure Ryan. As long as the pressure doesn't spike
over 100 psi on startup you should be fine, and the pressure will naturally drop as the oil warms up. General rule of thumb is don't go to full power (takeoff) until the oil temp is over 100 degrees.

On my engine I will see pressure around 80ish psi on a cold start and it will ultimately stabilize around 40-45 psi in cruise with hot oil.

I'm only up to my 8th flight now but on my 2.4L VW engine I'm getting between 35 and 40 PSI once the oil is up to temperature.
I get around 65PSI right after starting.
I've got an external oil filter and bottom mounted external oil cooler.
Are my numbers a bit lower than they should be?

That's a great question Michael. Unfortuately, there's no one specific answer.

Sonex says to run their AeroVee between 40-50 psi in cruise which is 3200 rpm.

Great Plains's operating limitations say the green arc for running their VW's is 23-70 psi.

Most automotive VW speciality shops recommend 10 psi per every 1000 engine rpm, so if you're running cruise at 3000 rpm you should see at least 30 psi. Or if you're running 3200 rpm then you should see 32 psi etc.

So as you can see, there's no one number. Personally since your engine is brand new and seems to be running sufficient oil pressure for normal operations, I would just run it and keep an eye on any pressure trends. If your pressure stays consistent, I'd say you're good to go! If it starts to drop then it will be something to keep an eye on.

Just my two cents of course...

rizzz wrote:I'm only up to my 8th flight now but on my 2.4L VW engine I'm getting between 35 and 40 PSI once the oil is up to temperature.
I get around 65PSI right after starting.
I've got an external oil filter and bottom mounted external oil cooler.
Are my numbers a bit lower than they should be?

On my first 125 hours 32psi was normal for all in-flight operations. After rebuilding my engine, 35 psi seems to be the norm. It has been in the low to mid 40s on startup, but once warm, I don't generally get anything over 35psi. So every engine is different, and Sonex says as long as that trend stays steady and I don't see pressure drops, that's an OK place to be.

That's good to hear,
I'll just keep an eye on it and watch for trend for now rather than focus too much on the actual value as long as it stays within the operating range.

Thanks Mike, Mike.
Regards,
Mike
:)

I have nearly 60 hours on my Aerovee. Using the recommended Valvoline VR1 20w 50 oil. I have had pressures in the mid to high 60's from day one with oil temps in the normal operating range at 3200 RPM.

Gripdana wrote:I have nearly 60 hours on my Aerovee. Using the recommended Valvoline VR1 20w 50 oil. I have had pressures in the mid to high 60's from day one with oil temps in the normal operating range at 3200 RPM.

Must be nice!! Do you cruise at 200 knots too?? :mrgreen:

I wish! But on my trip down to Ramona to meet up with Jim Hicke I was cruising at 8500 msl I saw 147 mph ground speed and 146 mph true for most of the trip home.