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vjdslk

Member
Group,

My oil pressure has always been slightly low, but on today?s warm
climb out (95 degree ambient) the OT got to about 205 and the pressure dropped to 66psi.*

I would really like to get it back up to the mid 70?s in cruise.* I
searched all over the net on adjusting the oil pressure relief valve.*I know you turn the set screw clockwise to increase pressure.*Pressure goes up 3-4 psi for every 360 degree turn of the adjustment screw.

The one thing I wasn?t able to find is how to physically do it.* My
relief valve is standard Lycoming adjustable with the castle head nut
on it.* The nut has a split pin through it I assume to stop it from
spinning.* My guess to make the adjustment is to drive the split pin
out of the nut so I can use a blade screw driver on the end to make
the adjustment and then reinstall the split pin?

Is this correct?

Thanks!

Jon D.
 
I have been told and also read from several sources that lower is better as long as you are in the recommended range. Not sure why exactly its recommended to stay in the lower end of the range but I don't think you have any problem. I would leave it alone.

George
 
Don't knock the pin out. Just use a hex wrench and turn it in. Can't remember if theres two nuts for a lock, but you are turning against a spring, so it seems like it doesn't back out on it's own. I'd have to look at it to make sure, but I know I didn't remove the pin. Gear heads here will respond soon I'm sure.
 
Just turn the nut which is pinned to the threaded shaft, no disasembly required :D
 
Walt, What are your feelings on pressure. Mine has been around 62 at cruise. Sky ranch has on their engine site that lower is better within limits. No explanation is given and I have noted others suggest higher is better.

George
 
I like to see 70 min with 75-80 being ideal (my preference).
Hot (220) oil will cause pressure to go down a little from 180 deg oil (5-10 psi normally) from what I've seen.
 
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