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funfly
20th Feb 2006, 15:31
I have a Lycoming Injected 360 on my aircraft.
I notice that on take-off the oil pressure goes up to about 100 psi - this is brought to my attention by my Engine Information System (which is set at 90 psi as maximum) bleeping and flashing at me!
Practical advice (not just "refer to the POH") would be of help. Shall I simply ignore this or will it prove bad for the engine or even could it cause a problem in flight. I am getting a bit neurotic about this but it only happens during the take off climb.
How serious a problem is this?

stiknruda
20th Feb 2006, 16:56
100 does seem a tad excessive - I set the bypass valve on my IO360 to give 80psi with power applied. It only wavers when in knife edge not on the pull.

Is your bypass valve set to high?

Stik

Mark 1
20th Feb 2006, 16:59
The pressure should be regulated by the relief valve (IIRC on the RH side in front of the accessory housing), and secondarily by the cooler bypass valve in case of cooler blockage. Surplus oil from the relief valve is returned to the sump.
I don't hold myself to be an expert, but possible causes may be:

defective relief valve,
defective pressure gauge,
Oil too viscous and cold exceeding the capacity of the relief valve (don't know if this is plausible).

Do you have an oil pressure gauge independent of the engine monitor? That may help to isolate it.

Defective gauges are a common 'cause' of oil pressure problems.

Are you still on a Summer grade of oil?

Does the problem only occur on the first flight from cold?

KZ8
20th Feb 2006, 18:36
funfly

Talk to your licensed engineer or PFA inspector as applicable and ask him/her to show you the pressure relief value on your engine and ask for them to adjust it for you.

According to my Lycoming Operators Manual:

Max oil pressure for normal operation is 90 psi
Min oil pressure for normal operation is 60 psi
Idling 25 psi

Max oil pressure for start and warm-up is 100 psi
Min oil pressure for start and warm-up is 55 psi
Idling 25 psi

The engine should be operating within this limits, ideally somewhere near the middle of the green arc (between 60 and 90) in the cruise to allow a margin each way.

100 psi is outside normal parameters.

Best

KZ8

A and C
24th Feb 2006, 06:48
I have nothing to add to the posts above on the wrong grade of oil for the OAT but have to ask if the engine has or in the recent past has had an oil leak from the center crank case joint or from the cylinder base ?.

If this is the case then PM or Email me because there are things that you should know before you fly this aircraft.

High Wing Drifter
24th Feb 2006, 07:59
As KZ8 has pointed out, I do see higher pressures at the start of the first flight of the day.