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2200A oil pressure

PostPosted: Fri Nov 03, 2017 7:02 pm
by The Red Baron
Hi All,

I'm very new to the world of Jabiru having just purchased my first aircraft, a 2002 SP-470. The engine has done 650 hours, but 160 since an overhaul.

I've done a couple of hours in her and noticed the oil pressure in cruise (2800 rpm) is around 32psi. Does that seem a bit on the low side? I've nothing to compare it to other than what it says in the engine manual.

What are others seeing as normal and, if mine is running on the low side, what could be the problem?

I appreciate any opinions. Many thanks in advance.

Ian.

Re: 2200A oil pressure

PostPosted: Fri Nov 03, 2017 8:14 pm
by Steevo
The Jab engine does run a bit low. The Jab specs say that down to 11psi is safe.

Mine tends to be about 60psi when the oil is cold but drops to the 30s and 40s when warmed up. Sometimes when coming in on final at idle power, the oil pressure will be just on the tip of the yellow on the gauge.

Some people fit a 3300 oil pump to bring the pressure up. I have heard good and bad things in doing this. Some say it brings the oil pressure up, others say that it just causes the oil pressure relief valve (PRV) to be constantly open.

There were small modifications to the oil pump. If you look at the Jab service bulletins, there are a couple on modifications to the 2200 oil pump. One you can do yourself if you are handy with a die grinder.

If it has been properly overhauled, then the oil pump mod has probably been done. You could try a 3300 pump or even a modification to the PRV. On the whole, I would say that your one sounds about normal.

What temperature does your oil typically run at in cruise? The hotter the oil, the thinner the oil, the lower the pressure.

Re: 2200A oil pressure

PostPosted: Fri Nov 03, 2017 8:51 pm
by The Red Baron
Thanks again, Steevo.

I'll take a look at the oil temp next time I'm up and see where that is.

It's reassuring to know the oil pressure isn't too far off the mark. From what I can make out in the manual for normal ops it should be between 31 and 76 psi. 11 psi is minimum for idle.

Just out of interest, what rpm do you set for cruise?

I'm keen to learn. I'll check out the Service Bulletins and see if the oil pump mod has been done.

Cheers.

Re: 2200A oil pressure

PostPosted: Fri Nov 03, 2017 10:05 pm
by skyjeep
your pressure sounds normal and there are lots of factors to change the perceived reading.
firstly the size of oil cooler adapter ports and hoses makes a big difference, lowering the gauge readout as flow restrictions reduce.
the temperature changes the pressure particularly as you reach the higher end of the permitted operating range.
most importantly, the safe way to measure engine oil pressure is at the gallery port, it is not used by the factory and closed with a threaded bung on the front face of the case. Changing the sensor to this port usually gives a reading 10 - 15psi less, so to avoid panic you need to alter your red line limits accordingly.
on a hot day, I see 18psi @ 3000 rpm cruise with oil temp around 200 F from this port. I'd rather fly with this indication - what the actual bearings are being delivered.

Re: 2200A oil pressure

PostPosted: Sat Nov 04, 2017 9:03 am
by Steevo
In cruise, I am normally at about 90-95kts at around 2700-2800 RPM.

As Skyjeep says, see where you are measuring your oil pressure. I changes my oil pressure sensor position when I got my Jab and it does make a difference.

Re: 2200A oil pressure

PostPosted: Sat Nov 04, 2017 5:18 pm
by Garyo
Type of filter make a diffrence as well I use a k & n and see a lower oil pressure, but with a jab filter i see a higher oil pressure, cannot remember the figures off the top of my head, my gauge is in bar as well, but always in the green band