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  #11  
Old 07-11-2018, 02:43 PM
lr172 lr172 is online now
 
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Originally Posted by maniago View Post
What you did is typical of changing from a long term use of a mineral base stock to a synthetic stock. You cleaned out the inside of your engine, esp rings, of gum/oil shelac etc that was keeping it happy with the Aeroshell.
Sorry, but detergents don't work that way. There is a reason that Lycoming has you ream the valve guides when the build up gets bad enough for the valves to stick. If detergents were enough to clear it, that would be their recommendation.

Detergents can help keep an engine clean by reducing build ups and remove certain, but limited, types of build up, like sludge. But they DO NOT clean out or remove the tough struff like coked oil and carbon deposits that create havoc for the ring and valve guide areas. Only the seriously nasty chemicals do that. One other potential problem the OP is experiencing is "stuck rings" due to the ring siezing in the ring land from carbon/coked oil build up. This reduces compression and increases blowby. IF that is what happened, it is likely the new oil took the problem over the provierbial hump by creating new build ups. Some have success with MMO and other treatments to free the rings, but most are solvent based chemicals and not detergents.

Larry
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Last edited by lr172 : 07-11-2018 at 03:22 PM.
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  #12  
Old 07-11-2018, 03:19 PM
erich weaver's Avatar
erich weaver erich weaver is offline
 
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Originally Posted by lr172 View Post
I never realized that cleaning coked oil and carbon out of the ring lands was as easy as simply changing to a semi-synthetic oil with Detergents.
Sarchasm aside, detergents can help keep an engine clean by reducing build ups and remove certain, but limited, types of build up, like sludge. But they DO NOT clean out or remove the tough struff like coked oil and carbon deposits that create havoc for the ring and valve guide areas.

While we are at it, Im not sure why folks routinely refer to 'detergents' in oil. I assume you must mean the ashless dispersant additive?

From the Phillips Technical Glossary available at

https://en.phillips66aviation.eu/pag...nical-glossary

"Detergent: A cleanliness additive made of metallic compounds to protect from sludge and varnish build-ups. Detergents are not allowed in aviation piston engine oils qualified under SAE J-1899 (obsolete MIL-L-22851) or SAE J-1966 (obsolete MIL-L-6082). No current aviation engine oil meeting the SAE J-1899 specification contains detergent compounds."

"Ashless Dispersant (AD):
A cleanliness additive for engine oils and widely used in aviation piston engines. Ashless dispersants do not contain metallic compounds and have no adverse affect on the break-in process."

Erich
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  #13  
Old 07-11-2018, 03:24 PM
lr172 lr172 is online now
 
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Originally Posted by erich weaver View Post
While we are at it, Im not sure why folks routinely refer to 'detergents' in oil. I assume you must mean the ashless dispersant additive?

From the Phillips Technical Glossary available at

https://en.phillips66aviation.eu/pag...nical-glossary

"Detergent: A cleanliness additive made of metallic compounds to protect from sludge and varnish build-ups. Detergents are not allowed in aviation piston engine oils qualified under SAE J-1899 (obsolete MIL-L-22851) or SAE J-1966 (obsolete MIL-L-6082). No current aviation engine oil meeting the SAE J-1899 specification contains detergent compounds."

"Ashless Dispersant (AD):
A cleanliness additive for engine oils and widely used in aviation piston engines. Ashless dispersants do not contain metallic compounds and have no adverse affect on the break-in process."

Erich
This was my understanding. AD is not a detergent. Its job is to keep particles in suspension. It's path to cleanliness is by keeping the bad stuff in suspension and not letting it form on parts or fall out and create sludge. The auto industry has been using detergent oils for years, in addition to dispersants, and it's primary role is to clean up or break up sludge build ups. It is a classic surfacant. However, sludge is not the nasty villan that causes the type of things we are discussing here. It is also not really an issue in the aviation world, due to the frequency of recommended oil changes. Sludge build up usually appears with MUCH longer drain intervals than we see in aviation.

Larry
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Last edited by lr172 : 07-11-2018 at 03:35 PM.
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  #14  
Old 07-11-2018, 03:37 PM
tim2542 tim2542 is offline
 
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Originally Posted by Charles in SC View Post
If you cannot find anything wrong maybe one of your hangermate/friends may be messing with you. Those engines are pretty bullet proof. Good luck and let us know what you find.
Removing oil? Thatís a seriously bad idea of a practical joke!
Tim Andres
Cozy MKIV....sold after 400 hrs
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  #15  
Old 07-11-2018, 03:57 PM
erich weaver's Avatar
erich weaver erich weaver is offline
 
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Quote:
Originally Posted by lr172 View Post
This was my understanding. AD is not a detergent.
I am well aware that AD is not a detergent; that is what my previous post clarified. What people dont seem to understand is that aviation oils do not contain detergents.

Enough thread drift

Erich
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  #16  
Old 07-11-2018, 07:59 PM
Charles in SC Charles in SC is offline
 
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Originally Posted by tim2542 View Post
Removing oil? Thatís a seriously bad idea of a practical joke!
Tim Andres
Cozy MKIV....sold after 400 hrs
Looking and lurking.
I hope not but I have seen some worse things done.
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  #17  
Old 07-17-2018, 09:12 AM
terrykohler terrykohler is offline
 
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Turns out the engine wasn't burning oil or blowing it out of the stacks. Problem was traced to a failed gasket on the plate of the rear accessory cover. Puzzled as to why this would show up after over 1100 hours and never being touched, but the fix and cost could have been much worse.

While we were at it, the compression was checked (good) plugs cleaned and gapped, ignition system inspected, and overall assessment completed. Only thing remaining is to clean and replace the air filter and possibly replace one EGT probe. The engine portion of my condition inspection is them complete.

Thanks for the many thoughtful replies to my call for help. Lots of knowledge on this forum and always an opportunity to learn something new.

Terry, CFI
RV9A N323TP
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  #18  
Old 07-17-2018, 09:57 AM
scsmith scsmith is offline
 
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A quart in 4 or 5 hrs from a gasket leak? Wow, that is a big leak!
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  #19  
Old 07-17-2018, 10:12 AM
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Originally Posted by scsmith View Post
A quart in 4 or 5 hrs from a gasket leak? Wow, that is a big leak!
And a lot of folks wasted a lot of time because you couldn't take the time to remove the cowls and look around for the obvious before posting about your "problem".
Maybe your time is more valuable than everyone elses?
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  #20  
Old 07-17-2018, 10:37 AM
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Mike S Mike S is offline
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Quote:
Originally Posted by terrykohler View Post
Turns out the engine wasn't burning oil or blowing it out of the stacks. Problem was traced to a failed gasket on the plate of the rear accessory cover.
I had a similar issue with the plate just below the right mag------turns out the nut at the bottom of the mag is really easy to miss, and the nut on the block off plate is just sitting there waiting for a chance to trick some poor soul into thinking they have just loosened the mag hold down.........
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