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ROTAX 914 LOW OIL PRESSURE

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RLINDSA2(at)san.rr.com
Guest

Posted: Mon Feb 23, 2009 3:17 pm Post subject: ROTAX 914 LOW OIL PRESSURE

Recently I had the need to climb to FL180 on a  below standard temp day.  Oil press in Rotax 914 UL3 (ser 4417756, 475 hrs)  has always been normal, but on this occasion while climbing 34 inches 5500 rpm  thru 15000 ft, oil pressure began decreasing (OAT was 10 deg below stnd).   At 18000 ft Grand Rapids EIS oil pressure alarmed at 25 psi.  Power was  retarded to below 65 percent and descent commenced.  Oil pressure returned  to normal (about 50 psi) below 15 Kft where OAT was near stnd.  Flight  continued at 12Kft at 75 percent power, all engine parameters indicating  normal.

  

 Oil quantity checked after landing indicated near  full.  Oil is Honda GN-4 10W40.  Oil pressure on several flights since  (altitude below 10 Kft) has been normal.

  

 Why would oil pressure drop under the above  conditions?  I suspect a sensing/indication problem.

  

 Thanx, all.  Bob Lindsay, Europa XS monogear  N77EU, San Diego CA

   [quote][b]

pjeffers(at)talktalk.net
Guest

Posted: Mon Feb 23, 2009 4:20 pm Post subject: ROTAX 914 LOW OIL PRESSURE

Hi Bob,

 

 The one piece of info you did not supply was what was the oil temp at this time?  You had apparently been climbing at max continuous for quite a while which inevitably gets the oil pretty warm.  My experience would indicate that even if the temp stays within limits (just) it will result in a significant reduction in oil pressure also within limits (just).  I suspect you are seeing a normal consequence of high oil temp. A higher air speed in climb or better cooling or both would probably have prevented the potential problem.

 

 Pete Jeffers

 

   

 

   

 

 --

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Mon Feb 23, 2009 4:24 pm Post subject: Re: ROTAX 914 LOW OIL PRESSURE

Most of these oil pressure issues tend to be sending units or bad grounds. If you really lose oil pressure you'll have some other serious issues to contend with.

_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

imap8ntr(at)cox.net
Guest

Posted: Mon Feb 23, 2009 4:41 pm Post subject: ROTAX 914 LOW OIL PRESSURE

As long as the oil is withing  limits (as opposed to being "hot")  I would assume that the pressure would  be fine.  After all is not that the function of the pressure  regulator?

  

 Ivan

  

  

 [quote]   ---

l_luv2_fly(at)yahoo.com
Guest

Posted: Mon Feb 23, 2009 6:04 pm Post subject: ROTAX 914 LOW OIL PRESSURE

Hi Bob,



One possibility is that you are getting oil foaming at altitude. I seem to recall John Hurst back in the days he was at Europa that he had a problem with some oils doing this.  



I can't remember which oil he had the most trouble with, but I seem to recall that he got good results with Valvoline Durablend.  



Paul



--- On Mon, 2/23/09, ROBERT LINDSAY <RLINDSA2(at)san.rr.com> wrote:

 	  Quote: 	
		  From: ROBERT LINDSAY <RLINDSA2(at)san.rr.com>

Subject: ROTAX 914 LOW OIL PRESSURE

To: rotaxengines-list(at)matronics.com

Date: Monday, February 23, 2009, 5:14 PM



       Recently I had the need to climb to FL180 on a  below standard temp day.  Oil press in Rotax 914 UL3 (ser 4417756, 475 hrs)  has always been normal, but on this occasion while climbing 34 inches 5500 rpm  thru 15000 ft, oil pressure began decreasing (OAT was 10 deg below stnd).   At 18000 ft Grand Rapids EIS oil pressure alarmed at 25 psi.  Power was  retarded to below 65 percent and descent commenced.  Oil pressure returned  to normal (about 50 psi) below 15 Kft where OAT was near stnd.  Flight  continued at 12Kft at 75 percent power, all engine parameters indicating  normal.

  

 Oil quantity checked after landing indicated near  full.  Oil is Honda GN-4 10W40.  Oil pressure on several flights since  (altitude below 10 Kft) has been normal.

  

 Why would oil pressure drop under the above  conditions?  I suspect a sensing/indication problem.

  

 Thanx, all.  Bob Lindsay, Europa XS monogear  N77EU, San Diego CA

    	  Quote: 	
		  	


	


         [quote][b]

RLINDSA2(at)san.rr.com
Guest

Posted: Mon Feb 23, 2009 8:04 pm Post subject: ROTAX 914 LOW OIL PRESSURE

Oil temp during my cruise climb of 100 KIAS was  actually a little cool at about 160 to 170F.

 [quote]   ---

RLINDSA2(at)san.rr.com
Guest

Posted: Mon Feb 23, 2009 8:13 pm Post subject: ROTAX 914 LOW OIL PRESSURE

I don't know what actually causes oil to  foam.  Honda GN-4 was recommended by Rotax rep Eric Tucker.  I plan on  trying to repeat the situation on a forthcoming high altitude  flight.

 [quote]   ---

ptag.dev(at)tiscali.co.uk
Guest

Posted: Tue Feb 24, 2009 1:12 am Post subject: ROTAX 914 LOW OIL PRESSURE

Hi!Bob Lindsey 

I had some "airating" oil problems with the 3300 Jabiru at one stage which showed ip as fluctuating pressure. I'd have thought Rotax being somewhat more pedantic would have a "de-airating tray" prior to the oil pump? 

I didn't notice any oil pressure deterioration at 10,000ft on mine. 

Regards 

Bob Harrison G-PTAG (Now with 914) 

  [quote]----Original Message----

From: RLINDSA2(at)san.rr.com

Date: 24/02/2009 4:12 

To: <rotaxengines-list(at)matronics.com>

Subj: Re: ROTAX 914 LOW OIL PRESSURE



   I don't know what actually causes oil to foam.  Honda GN-4 was recommended by Rotax rep Eric Tucker.  I plan on trying to repeat the situation on a forthcoming high altitude flight.

 [quote] ---

Ivor Phillips

Joined: 16 Jan 2006
Posts: 253
Location: London UK

Posted: Tue Feb 24, 2009 2:21 am Post subject: ROTAX 914 LOW OIL PRESSURE

Hi Bob

Rotax do have a  Mesh Baffle insert in the Oil tank just for that purpose,

A couple of years back Rotax remove  some oil Manufacturers from there recommended list because of foaming, I would stick with the recommended oil only,

regards

Ivor

---- "ptag.dev(at)tiscali.co.uk" <ptag.dev(at)tiscali.co.uk> wrote: 

[quote] 

 Hi!Bob Lindsey

 

 I had some "airating" oil problems with the 3300 Jabiru at one stage which showed ip as fluctuating pressure. I'd have thought Rotax being somewhat more pedantic would have a "de-airating tray" prior to the oil pump?

 

 I didn't notice any oil pressure deterioration at 10,000ft on mine.

 

 Regards

 

 Bob Harrison G-PTAG (Now with 914)

 

 

 

  

 ----Original Message----

 From: RLINDSA2(at)san.rr.com

 Date: 24/02/2009 4:12 

 To: <rotaxengines-list(at)matronics.com>

 Subj: Re: ROTAX 914 LOW OIL PRESSURE

 

 

 

 

 I don't know what actually causes oil to foam.  Honda GN-4 was recommended by Rotax rep Eric Tucker.  I plan on trying to repeat the situation on a forthcoming high altitude flight.

 

 ---

Roger Lee

Joined: 10 Jan 2006
Posts: 1464
Location: Tucson, Az.

Posted: Tue Feb 24, 2009 9:43 am Post subject: Re: ROTAX 914 LOW OIL PRESSURE

Oil foaming used to be a bigger issue a number of years back. That is why Rotax raised the oil level in the tank a few years back to help reduce the chance of sucking in air through the oil tank. Some oils do do have a propensity to foam more than others, but the semi synthetic and full synthetics of today are not as bad as they were many years ago or as bad as a straight dino oil. 

The least foaming of all the oils seems to be Amsoil (10-40 or 20-50 motorcycle oil). Mobile 1 Racing 4T, Aero Shell Sport Plus 4 and the Honda GN-4 oil are all good oils. I have seen Amsoil flown to 17K. You should not have any foaming issues with these oils. As Ivor pointed out Rotax has the wire mesh and the baffle plate inside the tank to help with sloshing and foaming.

Oil Comparison.pdf

Description:

Article to help understand oils.
Yes, it is written for AmsOil, but good basic info.

Download

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Oil Comparison.pdf

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_________________
Roger Lee
Tucson, Az.
Rotax Instructor & Rotax IRC
Light Sport Repairman
Home 520-574-1080 TRY HOME FIRST
Cell 520-349-7056

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Feb 24, 2009 10:54 am Post subject: ROTAX 914 LOW OIL PRESSURE

Oil foams when it gets hot and viscosity drops a little.  Teh beating of the oil pump is what froths it up.  Usually somewhere int the system there is a place where the oil is spun before the cooler to try to centrifugally  remove the air form the oil.  The 912 oil tank I have has the return line to the side of the tank in such a way as to spin the oil entering it... Airbubbles then rise and the pick up for the oil pump is at the bottom.  The idea being to avoid getting too much air in the oil returning to the cooler then to the engine.  

   

Noel  

       

From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of ROBERT LINDSAY

 Sent: Tuesday, February 24, 2009 12:42 AM

 To: rotaxengines-list(at)matronics.com

 Subject: Re: ROTAX 914 LOW OIL PRESSURE  

  

  

     

I don't know what actually causes oil to foam.  Honda GN-4 was recommended by Rotax rep Eric Tucker.  I plan on trying to repeat the situation on a forthcoming high altitude flight.  

    

----- Original Message -----   

    

From: Paul McAllister (l_luv2_fly(at)yahoo.com)   

    

To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)   

    

Sent: Monday, February 23, 2009 6:02 PM  

    

Subject: Re: ROTAX 914 LOW OIL PRESSURE  

    

   

          

Hi Bob,

   

   One possibility is that you are getting oil foaming at altitude. I seem to   recall John Hurst back in the days he was at Europa that he had a problem   with some oils doing this.  

   

   I can't remember which oil he had the most trouble with, but I seem to recall   that he got good results with Valvoline Durablend.  

   

   Paul

   

   --- On Mon, 2/23/09, ROBERT LINDSAY <RLINDSA2(at)san.rr.com>   wrote:   

From: ROBERT LINDSAY   <RLINDSA2(at)san.rr.com>

   Subject: ROTAX 914 LOW OIL PRESSURE

   To: rotaxengines-list(at)matronics.com

   Date: Monday, February 23, 2009, 5:14 PM         

Recently   I had the need to climb to FL180 on a below standard temp day.  Oil   press in Rotax 914 UL3 (ser 4417756, 475 hrs) has always been normal, but on   this occasion while climbing 34 inches 5500 rpm thru 15000 ft, oil pressure   began decreasing (OAT was 10 deg below stnd).  At 18000 ft Grand Rapids   EIS oil pressure alarmed at 25 psi.  Power was retarded to below 65   percent and descent commenced.  Oil pressure returned to normal (about   50 psi) below 15 Kft where OAT was near stnd.  Flight continued at 12Kft   at 75 percent power, all engine parameters indicating normal.   

      

    

      

Oil   quantity checked after landing indicated near full.  Oil is Honda GN-4   10W40.  Oil pressure on several flights since (altitude below 10 Kft)   has been normal.   

      

    

      

Why   would oil pressure drop under the above conditions?  I suspect a   sensing/indication problem.   

      

    

      

font face="Arial" size="2">Thanx,   all.  Bob Lindsay, Europa XS monogear N77EU, San Diego CA   

    	  Quote: 	
		    ist">http://www.matronics.com/Navigator?RotaxEngines-Listics.com.matronics.com/contribution 	


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_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

imap8ntr(at)cox.net
Guest

Posted: Tue Feb 24, 2009 1:56 pm Post subject: ROTAX 914 LOW OIL PRESSURE

I also had some fluctuating oil pressures in the past.  After changing out 

three sending units and having the same thing happen again,  I figured that 

it was impossible for it to be a defective sending unit.   Sure enough I 

concentrated on tidying us the wire connections a bit and it never happened 

again.

Ivan

Phoenix,  AZ



---

jlhazen(at)copper.net
Guest

Posted: Tue Feb 24, 2009 2:08 pm Post subject: ROTAX 914 LOW OIL PRESSURE

I had a problem with wildly fluctuating oil pressure.  Turned out to be a bad ground.



--- imap8ntr(at)cox.net wrote:



From: "Ivan" <imap8ntr(at)cox.net>

To: <rotaxengines-list(at)matronics.com>

Subject: Re: Re: ROTAX 914 LOW OIL PRESSURE

Date: Tue, 24 Feb 2009 14:55:14 -0700






I also had some fluctuating oil pressures in the past.  After changing out 

three sending units and having the same thing happen again,  I figured that 

it was impossible for it to be a defective sending unit.   Sure enough I 

concentrated on tidying us the wire connections a bit and it never happened 

again.

Ivan

Phoenix,  AZ



---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Wed Feb 25, 2009 6:47 am Post subject: ROTAX 914 LOW OIL PRESSURE

You will find when it comes to avionics or electrical systems on planes over 90% of problems you will find will be directly attributable to poor grounding  The other 10% of the time will be all the other things that can go wrong.  So when checking for possible problems, avionic or electrical distribution, first check all the appropriate grounding points are clean and strong.  Also check for bad crimps and make sure bundles are properly secured.  

Noel  

  

--

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

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