Oil Pressure question

[Frank DeBartolo]

Went flying today and noticed oil pressure was appx 29 or just under 30--I did a bunch of touch and goes after doing some chandelles, lazy 8's and some 720 power turns. The oil pressure gague usually stays right at 30 even at 1000-1500 or more rpmsThen after refueling and taxiing back to hangar I could not get the pressure over 20--even after giving some throttle to appx 1700-1800 rpm. Any feedback is appreciated.

Thanks,

Frank

[whake]

Re: Oil Pressure question

If the engine temperature is normal I would suspect the gage or a broken spring in the relief valve.

[Forrest Barber]

Re: Oil Pressure question

or a bit of crap in the relief valve, check it out!

[Frank DeBartolo]

Re: Oil Pressure question

Walt and Forrest,

Thanks for the info. I definitely will check it out. I will let all know what I find out.

Again,

Thanks,


Frank

[stormman]

Re: Oil Pressure question

Rev it high when the oils cold and if your lucky it might blow the crap out of the relef valve seat

[Frank DeBartolo]

Re: Oil Pressure question

I started it cold and the oil pressure came right up where it belongs. Had the IA look at it and we changed the oil and cleaned the oil screen and checked the spring. He thinks it was crap in the line and that it blew out. I never had this happen before--sooo I have another question. I have been using Aero Shell 80 AD with Avblend and Auto fuel that the FBO uses in his airplanes. The Auto fuel is 25% 100LL. I also use MMO. The FBO is very knowledgable and I am convinced that the auto fuel is a high grade (no ethanol).

Can the auto fuel cause crap in the engine and should I go back to 100LL. I have 170 hours since an extensive major overhaul and started using Mogas at 70 hours after the major OH. I used 100LL exclusively after the overhaul. The engine is a Continental A-65 with Millenium Cylinders. Would the new cylinders better handle the 100LL than the older cylinders.

Any feedback is appreciated.

Thanks,

Frank

[stormman]

Re: Oil Pressure question

I don't have my manual in front of me but i believe all the engine requires is something like 72 octane fuel and that was no lead fuel use the auto gas and a Mr Funnel water seperator funnel. As far as the fuel causing you problem? Naaaaaaaaa .. Use the 100 LL if your not going to fly in 30 days though.

[fearofpavement]

Re: Oil Pressure question

I have had similar oil pressure problems and usually they arose on an unusually cold day. (not on a T-craft) Anyway, if the oil pressure relief valve sticks open because it got pushed open farther than usual due to the thick oil, what is observed from the cockpit is that the oil pressure will continue to drop slowly as the engine warms up and more is bypassing the stuck open valve, maybe even into the yellow range. Most of the time this problem will cure itself after shutdown and cool down to ambient temperature but there have been times requiring removal and cleaning of the oil bypass valve. I woudn't worry about it much unless it reoccurs.

I doubt it has anything to do with fuel. Although on second thought if you didn't have any fuel in the plane it wouldn't have occurred so I guess there is a slight relationship...

[stormman]

Re: Oil Pressure question

relief valve sticks open because it got pushed open farther than usual due to the thick oil,

Forgot all about that!
The Fuel thing was funny too

[Frank DeBartolo]

Re: Oil Pressure question

Well, I have more to report about the oil pressure problem. I flew today and it was a great day to fly.

The Oil pressure went right up at start. Stayed at 30-31 psi throughout the flight. After landing, I shut it down and refueled. After refueling I started the airplane and no oil pressure. I waited 20 or so seconds and still no oil pressure then I shut it down. I Started it again and still no pressure. I tapped on the oil pressure instrument with my finger and the pressure immediately came up to 20psi and slowly raised toward 30 as I taxied to the hangar. At shut down the pressure stayed up for a while then slowly went down a little and then it went all the way down. I hope I explained everything OK.

Does it sound like I should order a new oil pressure instrument. My oil pressure gauge is 2 years old and is a Scott instrument and is FAA approved. Any comments are appreciated.

Thanks,

Frank

[Guest]

Re: Oil Pressure question

Does sound like a funky gauge.

Maybe its mounting is too tight and making it bind?

Dave

[stormman]

Re: Oil Pressure question

do the gage, Or buy one of them big tapping fingers

[mulwyk]

Re: Oil Pressure question

Norm:

It's true.

My 4th grade teacher would get my attention by tapping the top of my head with her finger. Ouch! I still have dents in my skull. She musta had one of them big tapping fingers.

Bob Gustafson

[cpirrmann]

Re: Oil Pressure question

Checking sender tubing for obstructions or kinks might be a good idea too.

[48fordnut]

Re: Oil Pressure question

borrow ,or buy one of the cheap auto gauges, disconnect yours and install .then do your run . those gauges are pretty reliable. I use one as i rebuild engs and build oil press on the eng stand.