Today's Message Index:
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1. 01:21 AM - Re: Low oil Pressure Indication Test Results (john firth)
2. 02:11 PM - Re: Low oil Pressure Indication Test Results (Hugh McKay)
Message 1
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| 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:
> Alright guys, I hope I don=92t 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=94 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. =46rom 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. =46rom 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@bellsouth.net
> http://www.wwegeo.com
> <Hugh.vcf><test results.docx>
Message 2
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| Subject: | Re: Low oil Pressure Indication Test Results |
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). I=92ll keep every one posted as I
continue to search for the =93gremlin=94!
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@bellsouth.net
http://www.wwegeo.com
From: john firth
Sent: Saturday, June 25, 2011 4:16 AM
Subject: Re: RotaxEngines-List: 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:
Alright guys, I hope I don=92t 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=94 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@bellsouth.net
http://www.wwegeo.com
<Hugh.vcf><test results.docx>
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