"We don't care what the idle oil pressure is"

[mhorowit]

When my instructor took the engine up for it's post-maintenance spin, he commented that when the engine had reached operating temp, and was running at idle, the oil pressure was just off the peg. The book says a range of between 10-35psi.

We mentioned it to the engine mechanic and he stated they didn't care what the pressure was at idle.

They are a respected firm, but that sounds screwy.

Anyone got an opinion one way or the other? - Mike

[alwaysoar]

Re: "We don't care what the idle oil pressure is"

As I posted earlier, the overhaul manual Table of Specifications gives the minimum idle as 10 psi, cruising 30-40 psi. Some other folks on that earlier thread said the same, quoting the TCDS. You might want to go back to that earlier thread, though "right off the peg" might be 10 psi. That's what it is! No less!

[flyguy]

Re: "We don't care what the idle oil pressure is"

My first -65 was completely worn out and it would even lose prime (no oil pressure at engine start up) if it set for a few days, but it still would produce 10 pounds of pressure at idle. (after the pump was primed and operating)
Just a W.A.G., your oil pump is really worn.
My 2 others, a 65 and an 85 produce(ed) 30 lbs or so at Idle.
Continental says ten minimum. It should be ten minimum. Sorry.
Darryl

[flyguy]

Re: "We don't care what the idle oil pressure is"

Now that I think about it though, that same worn out engine would give me 300 foot per minute at 12,500 FT (California winter) and go right past 65 redline in level flight. It was a 65 with 85 carb jets and venturi. Always ran fine except for the one time with the crap in the fuel. What can I say.
Darryl

[alwaysoar]

Re: "We don't care what the idle oil pressure is"

"Don't care what it is" is a p-poor response, but you're probably ok because as I said those gauges aren't all that accurate, and if it's off the peg then you've probably got enough oil pressure. The only alternative is an ugly one, that your oil gears are worn, or the cover, or all of the above--Didn't you just have your engine torn down and overhauled? The oil gears would be replaced or sent off and tagged if you had a major--a good one, that is.

[Mark Julicher]

Re: "We don't care what the idle oil pressure is"

FWIW,
I encountered an A-65 that behaved as you describe (i.e., 10 psi at idle and 30 psi at full throttle. When we tore it down the crankshaft bearing were worn beyond limits. New bearings fixed the low pressure.

[mhorowit]

Re: "We don't care what the idle oil pressure is"

Didn't you just have your engine torn down and overhauled? The oil gears would be replaced or sent off and tagged if you had a major--a good one, that is.

The folks who did the work are held in high esteem in the community.
I think, before I go off half-cocked, that I get my A&P to measure the pressure with a REAL meter, then go from there - Mike

[mhorowit]

Re: "We don't care what the idle oil pressure is"

FWIW,
I encountered an A-65 that behaved as you describe (i.e., 10 psi at idle and 30 psi at full throttle. When we tore it down the crankshaft bearing were worn beyond limits. New bearings fixed the low pressure.

New bottom half - Mike

[mhorowit]

Re: "We don't care what the idle oil pressure is"

As I posted earlier, the overhaul manual Table of Specifications gives the minimum idle as 10 psi, cruising 30-40 psi. Some other folks on that earlier thread said the same, quoting the TCDS. You might want to go back to that earlier thread, though "right off the peg" might be 10 psi. That's what it is! No less!

Yeah, but....
what's typical at idle?
Does every other A-65 have 15psi at idle, which would indicate this engine is marginal? - Mike

[Goneflyin]

Re: "We don't care what the idle oil pressure is"

Mike, when I bought my plane it had just had a crank, cam and new prop due to a prop strike (previous owner's father did the oops) but I found out after I had the plane a couple weeks and the pump lost it's prime a couple times they had put the worn rear case and gears back in. What was the pressure like and at what temp before the motor came apart?

Bill

[alwaysoar]

Re: "We don't care what the idle oil pressure is"

I don't know what's typical, but hot 15-50 which is what most people use will thin out a lot. I would find out if your oil pump gears and cover were replaced when the bottom end was done. That's not bottom end, but it's not all that expensive when the engine's out of the plane, unless you need an accessory case, and they're not that pricey from Capt Jon. I would find it hard to justify not doing that if you're doing the bottom end because the bottom end is dependent on good pressure.

[adrozell]

Re: "We don't care what the idle oil pressure is"

The idle oil pressure varies based on what type of oil you are using. Hear in Texas on a hot day with sae 40 you may barely be of the peg, but with 15-50 you will be at 25 to 30 psi. That is why with single weight oil you must do seasonal oil changes. If you look in the engine manual it should give you what oil to use for what tempters, or there is a Continental service bulletin stating that you may use multi viscosity oil. This would be your 15w50, or 20w50. I personally use multi viscosity to eliminate the problem of seasonal oil changes.

[Richard Boyer]

Re: "We don't care what the idle oil pressure is"

We have seasons in Texas????? Oh yeah! Summer and fall!

Richard Boyer
N95791
Georgetown, TX

[Yellow Duck]

Re: "We don't care what the idle oil pressure is"

Well fellows, thought I was about through. Started the Duck, first spin, ran beautiful, BUT no oil pressure either. Stopped and started three times let it run for a minute or so each time. Pulled the oil pressure line from the engine and primmed it again with oil into the engine, still no oil pressure.

Before all this, the oil pressure would jump up to 30# at the start up.

Tomorrow morning will pull the screen and double ck for trash or something. I had the hose plugged and the engine tube plugged also, to keep out the Bees and what have you.

When I pulled the engine, I did stand it on the rear end for a while, and oil dripped out, a bunch. But when I reinstalled it, I drained the oil that was left and added four quarts of 30 wt. st. min. oil.

Any other suggestions ??????

ps: sounds good with the new exhaust, but need oil pressure.

Thanks

[robbie]

Re: "We don't care what the idle oil pressure is"

Lee,
Remove the oil temp bulb,take a oil can and pump oil into the hole.
This will fill the oil pump case and gears with oil.
Sounds like all the oil is out of the pump.