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#11
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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
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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
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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
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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
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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
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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
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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
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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
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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
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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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