Attn: Hydraulic experts - oil pressure relief fix?

Okay, here's the deal.
snipped
Sounds like the oil pressure relief valve spring cound be hanging on the lip of
the spring retainer cap.
Take the cap off and chamfer the hole the spring goes into. Check for burrs on
the inside of the cap and also check the spring to see if it is bent or
deformed in any way.
(Shoots to top of yellow arc - 90 psi. I think all Lyc's do that.)
I dont think so. The oil pressure is generally higher when cold, 5 to 10psi or
so, and comes down to normal gradually when warm but does not jump suddenly.

Good luck,
Warren

Howdy Warren:

Sounds like the oil pressure relief valve spring cound be hanging on the lip
of
the spring retainer cap.
Take the cap off and chamfer the hole the spring goes into. Check for burrs
on
the inside of the cap and also check the spring to see if it is bent or
deformed in any way.

Okay, even tho I hadn't seen any burrs, I surfaced and chamfered the cap
anyway. I also tried to chamfer a bit the oil drain back holes in the cap, to
allow them to bleed when the ball just begins to move off the seat. Lastly, I
noticed the -3 washers that Lyc specifies seem a little too small. But -4's
are too large. So I ground down a -4 and put that in to minimize any spring
wobble on the washers.

I also forgot to put back one of the washers. The end result is that oil
pressure is better behaved, although I don't know which variable is
responsible. The oil pressure doesn't rise as high on takeoff as it used to
and still holds 60 psi when oil is hot. I keep meaning to watch to see if it
goes "sproing-g-g-g" but have been in the right seat and since it's not right
in front of my face, haven't noticed.

Thanks for the help so far... will squawk if the problem persists.

Mike Palmer
Excellence in Ergonomics

"MikeremlaP" wrote in message ...
Howdy Warren:

Sounds like the oil pressure relief valve spring cound be hanging on the lip
of
the spring retainer cap.
Take the cap off and chamfer the hole the spring goes into. Check for burrs
on
the inside of the cap and also check the spring to see if it is bent or
deformed in any way.

Okay, even tho I hadn't seen any burrs, I surfaced and chamfered the cap
anyway. I also tried to chamfer a bit the oil drain back holes in the cap, to
allow them to bleed when the ball just begins to move off the seat. Lastly, I
noticed the -3 washers that Lyc specifies seem a little too small. But -4's
are too large. So I ground down a -4 and put that in to minimize any spring
wobble on the washers.

I also forgot to put back one of the washers. The end result is that oil
pressure is better behaved, although I don't know which variable is
responsible. The oil pressure doesn't rise as high on takeoff as it used to
and still holds 60 psi when oil is hot. I keep meaning to watch to see if it
goes "sproing-g-g-g" but have been in the right seat and since it's not right
in front of my face, haven't noticed.

Thanks for the help so far... will squawk if the problem persists.

Mike Palmer
Excellence in Ergonomics



How thick are the washers? Do you know what the spring rate is, or do you know what the force is when the spring is
compressed to installed length? What is the size of the orifice/seat?

You are probably best off with a sharp edged seat where the ball sits, to minimize any hysteresis. You do not need a
leak free seal.

Most likely, loosing one of the washers was the reason for the lower regulated pressure....

Check out:
http://tinyurl.com/47d2w
http://tinyurl.com/5lqpd

Glad I could help, Mike.

Warren


Howdy Warren:

Sounds like the oil pressure relief valve spring cound be hanging on the lip
of
the spring retainer cap.
Take the cap off and chamfer the hole the spring goes into. Check for burrs
on
the inside of the cap and also check the spring to see if it is bent or
deformed in any way.

Okay, even tho I hadn't seen any burrs, I surfaced and chamfered the cap
anyway. I also tried to chamfer a bit the oil drain back holes in the cap,
to
allow them to bleed when the ball just begins to move off the seat. Lastly,
I
noticed the -3 washers that Lyc specifies seem a little too small. But -4's
are too large. So I ground down a -4 and put that in to minimize any spring
wobble on the washers.

I also forgot to put back one of the washers. The end result is that oil
pressure is better behaved, although I don't know which variable is
responsible. The oil pressure doesn't rise as high on takeoff as it used to
and still holds 60 psi when oil is hot. I keep meaning to watch to see if it
goes "sproing-g-g-g" but have been in the right seat and since it's not right
in front of my face, haven't noticed.

Thanks for the help so far... will squawk if the problem persists.

Mike Palmer
Excellence in Ergonomics