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I guess you kinda have to look at the oil relief valve as the "maximum allowable" oil pressure during cruise with fully warmed-up oil, while realizing that the oil pressure will run lower during idle -- but hopefully remaining "in the green".
Right -- so, turning the oil pressure relief screw-in (clockwise) increases both the idle and cruise oil pressure values. So now, I'm running "in the green" at idle (just above 60 psi) and 75 psi during cruise. Oil pressure goes up until hitting the maximum adjusted pressure, then it stays put.
No idea on position but Vegas odds for sensing positions would be both front galley (normally plugged) ports. I don't know where you could measure further downstream without some more involved surgery. Either way assuming accurate instrumentation, your "left" side has an ~7% flow loss and the "right" ~ 9.
One more important thing -- after getting your oil pressure set, make sure to safety-wire it because these things tend to back-off under engine vibration and lower the oil pressure over time. The safety wire can be run through the hollow split pinion-pin, that holds the adjustment nut onto the adjustment screw, down to the safety-wire hole provided on the engine casting (near the base of the oil pressure relief valve mount).
I think I will add this to my routine, and even if I break a lace occasionally, it's still more economical than what I'm doing!
For my next attempt, I am going to add ceaser salad dressing to my oil and observe the effect on sticking valves; In tribute to Mike busch, I will also force my cylinders to 300 and note the relationship, with and without the dressing.
So, are the monkeys in this story representative of the VAF members or the Lycoming Engineers?
I prefer to think of myself as the icy bucket of water. Still a theoretical threat, but mostly forgotten.So, are the monkeys in this story representative of the VAF members or the Lycoming Engineers?
Green arc(measured at rear) 55 to 95. Idle minimum 25. No need to worry about green arc for idle.
Great point about the #2 injector facing forward! I placed a "dam" in front of the #2 injector with the GAMI spread going from 0.6 GPH pre to 0.2 GPH post dam. My injectors are the "stock" injectors from Lycon. #2 always peaked peaked first before the dam was installed.
Can you post a picture of your damn?
Interesting thoughts here. I don't believe that excess flow from the lifter bore clearance flows to the rocker box. Yes, there is high pressure oil flowing to each lifter bore and clearances can be 3-4 thou. However, IIRC, that area has drains cast into the case to allow the excess flow to drain back to the sump. There would be a great deal of excess flow from that big of a clearance and that require drains. There is an area below the tube exit to collect this oil for the drain. It would be poor engineering if you allowed all that flow to go to the rocker box. Any blockage or leakage in that return sysem would quickly lead to serious issues. So, I don't believe that is a variable in this equation.
EDIT; amended my opinions in next post
,Today I looked at the engine in my garage and you are correct that some of the oil bled from the case bore / lifter clearance that comes out on the cylinder side (some comes out on the case side and drains to sump) has no case drain, except for the one at 3:00 or 9:00. I knew there was a drain, but didn't realize it was half way up the bore at 9:00; Thought it was at the bottom. Therefore oil will be delivered via the shroud tube and the quantity of that oil would be dependant upon the clearance between the lifter body and the case bore. Yeyt another variable in the mix.
Make that sample of 2. I also have been running peak EGT for 1000 hrs. I made the wobble test fixture and tested this year. Perfect.
FYI, the dam is held on with two existing screw holes: 1) #10 to the cylinder head, 2) #8 to the filter bracket. It's possible to drill those two holes on the bench without removing the baffle.
Jake is referring to the drain hole drilled in the 9:00 or 3:00 position in the case bore containing the lifter body. And is only exposed when the lifter is low in the bore. He was incorrect that it was an oil supply line. I confirmed it is just a drain line. Pics in my earliervpost. I have a 360 torn down in my garage right now. He is on to something though. There will be bleed oil coming from the clearance between the case bore and lifter body and the quantity of bleed oil will be directly related to the clearance there, which is .001-.006”. Because the drain is half way up the side of the bore, most of that that bleed oil will run down the shroud tube and drip onto the valve spring which will then drip on the valve stem, at least on the PV engines. Looks like on the av engines the angle will kind of miss the spring. Can see in your pic the gravity induced oil drip line from the tube. However, that oil should hit the spring and get thrown around via the constant movement and should end up with some oil on the stem.
Fully agreed, but creates an interesting difference betrween PV and AV. What was enlightening for me in that dialog was the oil coming down the tube. I always thought the drain hole for the lifter bleed oil was at the bottom of the bore. Learning that is on the side means that some portion of that bleed oil will come down the tube and end up in the rocker box. Prior, I had always believed that the only oil getting to the rocker box was via the pushrod. This adds another dimension to the speculation as to the randomness of sticking valves and influence via oil cooling.
And …..the other function of oil is lubricating obviously - hey, at least we’re having a good discussion on this.
Hi Dan, I’m embarrassed to say I did not measure the flow rate (my troubleshooting was done in the mid 90’s when I knew a lot less than now in reference to aircraft engines) however from memory, after running the engine at various revs for approx 5 mins, there was about 1/2” of oil in the cans for #2 & #4 and about a teaspoon each for #1 & #3 that shocked me enough at the time.
My understanding is that as long as there is mineral component in the oil it would cook up on the valve guide. Fully synthetic oil + unleaded fuel seems to be the ultimate solution as it's much more resistant to to high temperatures
Agreed.. Mobil av1 failure was the lack of lead scavenging. Unleaded fuel would eliminate that aspect. New top tier autos are leaving factories with full synthetic now. Again, unleaded fuel
i agree that oil is not a lead scavenger, but am struggling with lead not being held in suspension, as i have pulled a few engines apart with minimal to no sludge and if the lead was not being held in suspension, there should be a LOT of grey sludge at the bottom of the pan after a couple thousand hours. The fact that it is not there makes my question that claim. I do see a LOT of grey sludge in the forward crank core, where the force acts like a centrifuge and pulls the lead out of suspension and sticks to the wall. This stuff should be everywhere if unable to be held in suspension, yet it is not.
