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  #11  
Old January 29th 07, 11:16 PM posted to rec.aviation.owning
Ross
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Posts: 463
Default dirty oil

Nathan Young wrote:
On Mon, 29 Jan 2007 13:49:26 -0600, "Dan Luke"
wrote:


wrote:


Definitely have an A&P borescope that engine. Broken ring maybe.


Talked to my mechanic this morning. He said not to worry; the dirty oil is


from the oil cooler and its plumbing, which don't get drained when the oil is


changed.

He said I would have noticed this before if I had ever checked it two hours
after a change. Since I check the oil before every flight, it seems I would
have noticed the oil's turning black this soon before.

Should I pay to have the cylinders 'scoped?



Your mechanic's comment sounds unrealistic. I have a hard time
believing the 1/2 quart in the cooler & lines could add enough
coloration to the 7-8 quarts of new/clean oil.

Further, I don't notice my oil turning black until many hours after
the change. (Lyc O-360 using Aeroshell 15W50), and I never flush the
cooler during a change.

Is your oil a dark black? Or just a tinge of coloration?


I have a Lyc O-360 on my Cessna and there is a oil cooler. I have never
had dirty oil after only a couple of hours of operation. I would keep
looking.

--

Regards, Ross
C-172F 180HP
KSWI
  #12  
Old January 30th 07, 12:14 AM posted to rec.aviation.owning
Kyle Boatright
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Posts: 578
Default dirty oil


"Dan Luke" wrote in message
...

wrote:

Definitely have an A&P borescope that engine. Broken ring maybe.


Talked to my mechanic this morning. He said not to worry; the dirty oil
is from the oil cooler and its plumbing, which don't get drained when the
oil is changed.

He said I would have noticed this before if I had ever checked it two
hours after a change. Since I check the oil before every flight, it seems
I would have noticed the oil's turning black this soon before.

Should I pay to have the cylinders 'scoped?

--
Dan
C-172RG at BFM


My 0-320 powered RV has an oil cooler with the associated plumbing. The oil
still looks like honey 20 and more hours after a change. It has never been
dark after only a few hours.

You could perform a simple compression check. Turn the mags off, chock the
airplane, and pull the top plug from each cylinder. With someone else slowly
rotating the prop, do a thumb test over the plug hole for compression on all
4 cylinders. You should be able to notice if one cylinder is considerably
worse than the others.

As always, treat the engine/prop as if the engine is going to start abruptly
anytime you're moving the prop.

KB


  #13  
Old January 30th 07, 12:43 AM posted to rec.aviation.owning
[email protected]
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Posts: 111
Default dirty oil

I would test your mechanics theory by doing another oil change, this
time making sure I drained the cooler and changed the filter (which I
always do since my cooler has a drain cap, and like the others who
have stated so, my oil stays so clean for several hours after a change
that it is hard to read the dipstick in certain light situations). See
what happens then. You can keep the oil you have now and use it a
quart at a time in the near future if all is OK.
Also, the Cardinal club has a technical page (members only), that
shows an owner who made a small slim light from a flashlight bulb and
wire that was small enough to fit thru the spark plug hole. If you
remove both plugs, and slide the light in one hole and look through
the other, you can see if the cylinder is glazed or if there is a
major problem. Not as good as borescope, but better than nothing.
As a matter of fact, I put a reworked cylinder on #4 of my O-360
8 hrs ago. I am still running the Mineral break in oil, and the oil is
still almost clear and it is hard to read the stick, even though I
don't have fully seated rings yet on one ccylinder (chrome cylinder),
and I did not change the filter when I put the break in oil in since I
only do that every other oil change, and I am going to change back to
AD at 10 hours when I will change the filter, drain the cooler, and
add Aeroshell 15W-50.
I have had a forced landing, and can tell you from experience,
you must do whatever you need to, to prevent having one yourself.
Keeping that fan turning matters as much as anything there is. I was
lucky with no injury or damage. I am sure my next time I will not be
so fortunate. Know what you are dealing with!!

Regards,
Bud

On Jan 29, 11:49 am, "Dan Luke" wrote:
wrote:
Definitely have an A&P borescope that engine. Broken ring maybe.Talked to my mechanic this morning. He said not to worry; the dirty oil is

from the oil cooler and its plumbing, which don't get drained when the oil is
changed.

He said I would have noticed this before if I had ever checked it two hours
after a change. Since I check the oil before every flight, it seems I would
have noticed the oil's turning black this soon before.

Should I pay to have the cylinders 'scoped?

--
Dan
C-172RG at BFM


  #14  
Old January 30th 07, 03:12 AM posted to rec.aviation.owning
[email protected]
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Posts: 111
Default dirty oil

Also, I would send a sample of the oil in the engine to a good lab
like Spectro or Blackstone. See if there is a large amount of metal in
it.

Bud


On Jan 29, 11:49 am, "Dan Luke" wrote:
wrote:
Definitely have an A&P borescope that engine. Broken ring maybe.Talked to my mechanic this morning. He said not to worry; the dirty oil is

from the oil cooler and its plumbing, which don't get drained when the oil is
changed.

He said I would have noticed this before if I had ever checked it two hours
after a change. Since I check the oil before every flight, it seems I would
have noticed the oil's turning black this soon before.

Should I pay to have the cylinders 'scoped?

--
Dan
C-172RG at BFM


  #15  
Old January 30th 07, 03:22 AM posted to rec.aviation.owning
A Lieberma
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Posts: 318
Default dirty oil

Nathan Young wrote in
:

Further, I don't notice my oil turning black until many hours after
the change. (Lyc O-360 using Aeroshell 15W50), and I never flush the
cooler during a change.


For what it's worth.....

I have never had oil discolored significantly before 5 hours running time.
Right around 10 hours does the oil start to look like used oil in my
Lycoming AK4 360 engine.

Allen

  #16  
Old January 30th 07, 04:28 AM posted to rec.aviation.owning
Roger[_4_]
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Posts: 677
Default dirty oil

On Mon, 29 Jan 2007 13:49:26 -0600, "Dan Luke"
wrote:


wrote:

Definitely have an A&P borescope that engine. Broken ring maybe.


Talked to my mechanic this morning. He said not to worry; the dirty oil is
from the oil cooler and its plumbing, which don't get drained when the oil is
changed.

He said I would have noticed this before if I had ever checked it two hours
after a change. Since I check the oil before every flight, it seems I would
have noticed the oil's turning black this soon before.


I guess it's possible, but on the Deb the oil stays clean until around
15 to 20 hours and that is without an oil filter. Compression is in
the low 70s. If you take the breather cap off and pull the prop
through by hand, the old girl really wheezes. Doesn't use a drop of
oil between changes though, well at least not enough to notice on the
dip stick.


Should I pay to have the cylinders 'scoped?


I think I'd have the compression checked at least
Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com
  #17  
Old January 30th 07, 06:37 AM posted to rec.aviation.owning
Stan Prevost[_1_]
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Posts: 71
Default dirty oil

Dan, I guess a lot of things can contribute to rapid blackening of the oil,
but in all cases it will be because some black stuff is being added to the
oil, and there is some source of the black stuff. In a previous Lyc
TIO-540-S1AD, I had bad exhaust valve guides. Hot gases blew through the
sloppy guides and burned oil in the rocker box. There was lots of black
stuff in the rocker box, and oil and suspended black stuff drains from there
back into the engine.

For pix, see http://aviation.sprevost.net/Engine-Photos/Cyl-Nr-1.jpg and

http://aviation.sprevost.net/Engine-Photos/Cyl-Nr-2.jpg for a bad one and a
good one.

Compressions were good until the problem got really bad. Then valve springs
and anything else that gets in the way gets burned.

It is easy to see if you have this problem by opening the rocker boxes.

Stan



"Dan Luke" wrote in message
...

wrote:

Definitely have an A&P borescope that engine. Broken ring maybe.


Talked to my mechanic this morning. He said not to worry; the dirty oil
is from the oil cooler and its plumbing, which don't get drained when the
oil is changed.

He said I would have noticed this before if I had ever checked it two
hours after a change. Since I check the oil before every flight, it seems
I would have noticed the oil's turning black this soon before.

Should I pay to have the cylinders 'scoped?

--
Dan
C-172RG at BFM



  #18  
Old January 30th 07, 01:14 PM posted to rec.aviation.owning
Dan Luke
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Posts: 678
Default dirty oil


"dlevy" wrote:

How fast does it burn oil?


1 qt/7.5 hours.

there was a period of inactivity?


No.

Do you foul plugs?


No.

When was the last overhaul?


2001


--
Dan
C172RG at BFM


  #19  
Old January 30th 07, 01:17 PM posted to rec.aviation.owning
Dan Luke
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Posts: 678
Default dirty oil


"Stan Prevost" wrote:
Compressions were good until the problem got really bad. Then valve springs
and anything else that gets in the way gets burned.

It is easy to see if you have this problem by opening the rocker boxes.


Good idea. Thanks, Stan.

--
Dan
C172RG at BFM


  #20  
Old January 30th 07, 01:21 PM posted to rec.aviation.owning
Jim Carter[_1_]
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Posts: 403
Default dirty oil



-----Original Message-----
From: Stan Prevost ]
Posted At: Monday, January 29, 2007 11:38 PM
Posted To: rec.aviation.owning
Conversation: dirty oil
Subject: dirty oil

....
... In a previous Lyc
TIO-540-S1AD, I had bad exhaust valve guides. Hot gases blew through

the
sloppy guides and burned oil in the rocker box. There was lots of

black
stuff in the rocker box, and oil and suspended black stuff drains from
there back into the engine.

For pix, see http://aviation.sprevost.net/Engine-Photos/Cyl-Nr-1.jpg

and

http://aviation.sprevost.net/Engine-Photos/Cyl-Nr-2.jpg for a bad one

and
a
good one.


Outstanding example photos Stan. Thanks...

 




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