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hgmckay
Joined: 23 May 2006
Posts: 397
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 Posted: Thu Jun 23, 2011 4:10 pm Post subject: Low oil Pressure Indication Test Results |
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Alright guys, I hope I don’t screw things up again. Here are the results (attached as a word document) of the final (on the ground) test to reconcile the difference between the VDO electric oil pressure gauge readings in the cockpit (which reads in bars) vs. a direct mechanical oil pressure gauge readings. I had a 1/8” line coming directly from the engine port where the oil pressure sender unit is normally attached out to a tee where I attached a new (Lockwood) oil pressure sending unit which was connected to the VDO gauge in the cockpit, and then reduced down to a very small nylon tube connecting to a mechanical oil pressure gauge (range 0-100 psi). The conditions of the test were 455 hours on the engine, engine has the Rotax replacement oil pressure regulator parts installed (new mushroom head, spring and cap screw), ambient temperature was 79 degrees F, oil is Mobil 1 Racing 4T, plane level and tied down securely. >From these results I am satisfied that I do NOT have a low oil pressure problem in my engine.
Because the pressure sending unit is brand new, I do not believe that is the problem causing low pressure readings on the VDO gauge in the cockpit. From these results I suspect I have either a VDO gauge that has gone bad, or a grounding/partial grounding problem. Any comments??
Hugh G. McKay III, P.E.
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Allegro 2000 ELSA
Rotax 912 UL
N661WW
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
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craig(at)craigandjean.com
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| Posted: Thu Jun 23, 2011 4:25 pm Post subject: Low oil Pressure Indication Test Results |
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I’ve converted the MS Word file to an Adobe Acrobat PDF so anyone can read it (although MS does offer a free doc/docx reader). PDF attached.
-- Craig
From: owner-rotaxengines-list-server(at)matronics.com [mailto:owner-rotaxengines-list-server(at)matronics.com] On Behalf Of Hugh McKay
Sent: Thursday, June 23, 2011 5:08 PM
To: Rotax Engines
Subject: Low oil Pressure Indication Test Results
Alright guys, I hope I don’t screw things up again. Here are the results (attached as a word document) of the final (on the ground) test to reconcile the difference between the VDO electric oil pressure gauge readings in the cockpit (which reads in bars) vs. a direct mechanical oil pressure gauge readings. I had a 1/8” line coming directly from the engine port where the oil pressure sender unit is normally attached out to a tee where I attached a new (Lockwood) oil pressure sending unit which was connected to the VDO gauge in the cockpit, and then reduced down to a very small nylon tube connecting to a mechanical oil pressure gauge (range 0-100 psi). The conditions of the test were 455 hours on the engine, engine has the Rotax replacement oil pressure regulator parts installed (new mushroom head, spring and cap screw), ambient temperature was 79 degrees F, oil is Mobil 1 Racing 4T, plane level and tied down securely. From these results I am satisfied that I do NOT have a low oil pressure problem in my engine.
Because the pressure sending unit is brand new, I do not believe that is the problem causing low pressure readings on the VDO gauge in the cockpit. From these results I suspect I have either a VDO gauge that has gone bad, or a grounding/partial grounding problem. Any comments??
Hugh G. McKay III, P.E.
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Allegro 2000 ELSA
Rotax 912 UL
N661WW
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
| | - The Matronics RotaxEngines-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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dashwood
Joined: 24 Jan 2009
Posts: 73
Location: sw ontario canada
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| Posted: Fri Jun 24, 2011 4:04 am Post subject: Re: Low oil Pressure Indication Test Results |
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quote "From these results I am satisfied that I do NOT have a low oil pressure problem in my engine".
and what have we learned...... assemble and analyze all the posts with vdo and electric oil and the conclusion would be???? get a system that is reliable and consistent so you can read patterns and react to problems that are real and urgent. #1 problem with flying and induced pilot errors.... second guessing your instruments. At 400+ hrs.. what is the condition of the gearbox? have you had it apart to look at the shims? what is the magnet plug indicating?have you experimented with other oils on the suggested/ approved list?
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_________________
Ross Alexander: CH701 driver 912ul 788tt
It only takes two things to fly, airspeed and money |
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john firth
Joined: 29 Jan 2011
Posts: 11
Location: Yorkshire England
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| Posted: Sat Jun 25, 2011 12:21 am Post subject: Low oil Pressure Indication Test Results |
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Hello Hugh, have you a voltmeter to monitor the system voltage whilst doing the tests. It is possible that changing voltage could affect the reading of an electrical gauge.Cheers, john firth.
G-JULZ
On 24 Jun 2011, at 01:07, Hugh McKay wrote:
[quote] Alright guys, I hope I dont screw things up again. Here are the results (attached as a word document) of the final (on the ground) test to reconcile the difference between the VDO electric oil pressure gauge readings in the cockpit (which reads in bars) vs. a direct mechanical oil pressure gauge readings. I had a 1/8 line coming directly from the engine port where the oil pressure sender unit is normally attached out to a tee where I attached a new (Lockwood) oil pressure sending unit which was connected to the VDO gauge in the cockpit, and then reduced down to a very small nylon tube connecting to a mechanical oil pressure gauge (range 0-100 psi). The conditions of the test were 455 hours on the engine, engine has the Rotax replacement oil pressure regulator parts installed (new mushroom head, spring and cap screw), ambient temperature was 79 degrees F, oil is Mobil 1 Racing 4T, plane level and tied down securely. From these results I am satisfied that I do NOT have a low oil pressure problem in my engine.
Because the pressure sending unit is brand new, I do not believe that is the problem causing low pressure readings on the VDO gauge in the cockpit. From these results I suspect I have either a VDO gauge that has gone bad, or a grounding/partial grounding problem. Any comments??
Hugh G. McKay III, P.E.
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Allegro 2000 ELSA
Rotax 912 UL
N661WW
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
<Hugh.vcf><test results.docx>[b]
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hgmckay
Joined: 23 May 2006
Posts: 397
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| Posted: Sat Jun 25, 2011 1:11 pm Post subject: Low oil Pressure Indication Test Results |
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John,
Yes I have a volt meter in the plane. Voltage is steady. I am going to pull the panel out enough to get to all the ground connections behind the panel and check all the other grounding points on the plane first to make sure they are all good. If they are all good solid grounds, it would seem to be the VDO instrument itself. The sending unit itself seems to be good because the Mechanical gauge indicated good oil pressure as noted in my tabulated results. The pressure indication on the VDO comes up to 4 bar (58 psig) as soon as the engine cranks. But, within a few minutes while taxing the VDO pressure begins to drop off down to the 2 bar (29 psig). On take off with the engine at max throttle the VDO gauge shows about 3 bar (43.5 psig). At cruise the VDO shows around 2.0 2.3 bar (29-33.35 psig). Ill keep every one posted as I continue to search for the gremlin!
Hugh G. McKay III, P.E.
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net
http://www.wwegeo.com
From: john firth (firth942(at)btinternet.com)
Sent: Saturday, June 25, 2011 4:16 AM
To: rotaxengines-list(at)matronics.com (rotaxengines-list(at)matronics.com)
Subject: Re: Low oil Pressure Indication Test Results
Hello Hugh, have you a voltmeter to monitor the system voltage whilst doing the tests. It is possible that changing voltage could affect the reading of an electrical gauge. Cheers, john firth.
G-JULZ
On 24 Jun 2011, at 01:07, Hugh McKay wrote:
| Quote: | Alright guys, I hope I dont screw things up again. Here are the results (attached as a word document) of the final (on the ground) test to reconcile the difference between the VDO electric oil pressure gauge readings in the cockpit (which reads in bars) vs. a direct mechanical oil pressure gauge readings. I had a 1/8 line coming directly from the engine port where the oil pressure sender unit is normally attached out to a tee where I attached a new (Lockwood) oil pressure sending unit which was connected to the VDO gauge in the cockpit, and then reduced down to a very small nylon tube connecting to a mechanical oil pressure gauge (range 0-100 psi). The conditions of the test were 455 hours on the engine, engine has the Rotax replacement oil pressure regulator parts installed (new mushroom head, spring and cap screw), ambient temperature was 79 degrees F, oil is Mobil 1 Racing 4T, plane level and tied down securely. From these results I am satisfied that I do NOT have a low oil pressure problem in my engine.
Because the pressure sending unit is brand new, I do not believe that is the problem causing low pressure readings on the VDO gauge in the cockpit. From these results I suspect I have either a VDO gauge that has gone bad, or a grounding/partial grounding problem. Any comments??
Hugh G. McKay III, P.E.
Senior Consultant
Worldwide Engineering Inc.
4090 North NC Hwy. 16
Denver, NC 28037
Allegro 2000 ELSA
Rotax 912 UL
N661WW
Ph. 704-661-8271
Fax 704-483-5466
email hgmckay(at)bellsouth.net (hgmckay(at)bellsouth.net)
http://www.wwegeo.com
<Hugh.vcf><test results.docx> |
[quote]
href="http://www.matronics.com/Navigator?RotaxEngines-List">http://www.matronics.com/Navigator?RotaxEngines-List
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href="http://www.matronics.com/contribution">http://www.matronics.com/c
[b]
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