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How Many Hours Between Oil Changes?


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8 hours ago, Godfather said:

200 hrs per year - 40-50 hr interval 

100 hrs per year - 30 hr interval

The main problem is sitting.  Not hours running.  if you are only flying 75 hours a yesr then you should be changing every 20-30 hours.  if flying 150 hours a year, 40-50 hours works fine.

Why use costly synthetic if you are only going to run it 20-50 hours between changes?

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I fly about 125 hours a year, try to keep changes at 25 hours but have gone to 33. New filter and Blackstone analysis each change. Having been at the CamGuard presentation at Mooney Summit 2016, I use Aeroshell W100 and CamGuard. 

Longer intervals and synthetic oil with our late model cars does not apply to aviation engines with loose tolerances. 

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 I'm not sure where I heard or read this but after completely draining the oil  it's been suggested by some that you pour some 100LL fuel  through the oil filler spout and let it drain out the bottom  drain plug.  I suppose the idea is to wash out any sludge or residual dirty oil.  If the engine was warm prior to draining the oil, any residual fuel in the crankcase would evaporator rather quickly. 

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6 hours ago, L. Trotter said:

 I'm not sure where I heard or read this but after completely draining the oil  it's been suggested by some that you pour some 100LL fuel  through the oil filler spout and let it drain out the bottom  drain plug.  I suppose the idea is to wash out any sludge or residual dirty oil.  If the engine was warm prior to draining the oil, any residual fuel in the crankcase would evaporator rather quickly. 

I have heard this mentioned several times over the years. While, it might be effective in washing out some sludge, I would question the wisdom of pouring avgas into a warm/hot engine. Seems to me a good way to encounter a vapor cloud fire.   Avgas works good as a cleaning solvent, but mechanics don't use it because of the flammability hazard.

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9 hours ago, Chupacabra said:

I fly about 125 hours a year, try to keep changes at 25 hours but have gone to 33. New filter and Blackstone analysis each change. Having been at the CamGuard presentation at Mooney Summit 2016, I use Aeroshell W100 and CamGuard. 

 

Aeroshell W100 already has anti-wear additives similiar to Cam Guard, using both is a waste. 

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12 minutes ago, MBDiagMan said:

Aeroshell 100 PLUS is th one with CAMGUARD included.  If it doesn't have PLUS in the name it doesn't have camguard.

That's incorrect. The plus version has a small amount of Triphenyl phosphate for an anti-scuff additive. It also breaks down into acid when exposed to water vapor.  

Camguard is a blend of 25 substances. 

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10 minutes ago, MBDiagMan said:

Aeroshell 100 PLUS is th one with CAMGUARD included.  If it doesn't have PLUS in the name it doesn't have camguard.

Plus has several additives over non-Plus, but it doesn't include the Camguard additive package.  It does include the Lycoming anti-wear LW16702 which meets Lycomings suggestion/requirement.

The Camguard additive package was apparently too expensive to include.  Since sp many people use Camguard now, I'm surprised that none of the oil companies sell a version including Camguard.  With their volumes, they could sell the oil/Camguard combo for less than what we pay currently and mix ourselves.

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17 minutes ago, clh said:

I have heard this mentioned several times over the years. While, it might be effective in washing out some sludge, I would question the wisdom of pouring avgas into a warm/hot engine. Seems to me a good way to encounter a vapor cloud fire.   Avgas works good as a cleaning solvent, but mechanics don't use it because of the flammability hazard.

I grew up in my Dad's independent auto repair shop.  I have lots of car and truck engine experience even though I was an engineer during most of my career.  

In the old days, yes I am plenty old enough to remember the old days, motor oil was primitive and lacking to say the least.  In addition, engine cooling systems operated at low temperatures and there were road draft tubes for crankcase ventilation rather than modern positive crankcase ventilation.  Oil had to be changed REALLY often or it would gunk up fast.  When it did, measures such as pouring a solvent in the crankcase was sometimes, maybe even often, necessary.  When we resorted to that we used kerosene or maybe diesel fuel very carefully.  These solvents are slightly oily so they are not as likely to remove the oil film from between the bearings and crankshaft/camshaft surfaces.

With modern oils and engines, if the oil is changed even on the outer limits of reccommended oil change interval, there should never be a sludge problem to the point of needing use of a solvent.  Even in your old design aircraft engine, unless it has been neglected you should never have to remove sludge.  You CERTAINLY would not want to pour solvent through an engine as a preventive maintenance measure.  Pouring solvent through the crankcase should be considered as a last resort ditch effort.  Most especially a hot solvent like gasoline.  Gasoline would most likely remove at least part of, but probably ALL of the oil film between bearings and bearing surfaces which would make the next loaded movement of that bearing before the film was replenished by the oil pump very destructive.

Pouring solvent in the crankcase of an old neglected farm truck in an effort to get one more season of hay hauling would be one thing.  Doing the same thing to an engine worth twenty times as much as that old hay truck as a preventive maintenance measure is quite different.

my $0.02,

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Just now, Cyril Gibb said:

Plus has several additives over non-Plus, but it doesn't include the Camguard additive package.  It does include the Lycoming anti-wear LW16702 which meets Lycomings suggestion/requirement.

The Camguard additive package was apparently too expensive to include.  Since sp many people use Camguard now, I'm surprised that none of the oil companies sell a version including Camguard.  With their volumes, they could sell the oil/Camguard combo for less than what we pay currently and mix ourselves.

Thanks very much for the clarification Cyril!  Sounds like the PLUS as opposed to the 100 is still the way to go for a Lycoming?

My Mooney was annualed with Philips Crosscountry oil when I bought it.  I use Aeroshell plus in my Cessna, although it is a Continental.  I have given thought to changing the Mooney to the Aeroshell at the next change to make it easier to keep oil around.

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5 minutes ago, MBDiagMan said:

Thanks very much for the clarification Cyril!  Sounds like the PLUS as opposed to the 100 is still the way to go for a Lycoming?

That's not what I do.  It meets Lycomings stated minimum requirement.  There are no objective findings to say Camguard is superior.  However, after reading the background of the Camguard guy and the rationale of the additive package, I use Phillips 20-50 and Camguard.

Because there are no objective findings of Camguard advantages, I would not give an opinion of what others should do.  But I use it.

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Just now, MBDiagMan said:

Fair enough Cyril!  Maybe I should stay with the Philips and add the CAMGUARD.

Not intending to start an argument...but there have been a rash of engines with stuck valves that were running Phillips, do a little research and you'll see what I am talking about. 

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We change at 4 months or a case of oil, whichever comes first, usually about 30 - 35 hours.

Our plane pretty consistently goes through a quart every 5 hours if we keep it between 5 and 6 quarts.  When we do the oil change we buy a case of oil and use 6 quarts plus 10 oz of Camguard.  That leaves us with 6 quarts in the locker.  When we've used up all the oil and we are down around 5 quarts in the engine, we change the oil.

When we change the oil we:

Use Phillips 20W50XC, a new filter (been using Champion but switching to Tempest), Camguard, and do an oil analysis.

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I use Shell 100+ and change oil at 30 hour intervals. I do not use cam guard or any other additive. This has been my policy for my Mooneys and the engines (and cams) showed little wear that could be attributable to oil. To be fair I live in a benign climate and fly every week.


Sent from my iPhone using Tapatalk

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7 hours ago, N6758N said:

Not intending to start an argument...but there have been a rash of engines with stuck valves that were running Phillips, do a little research and you'll see what I am talking about. 

Data?  "Rash of engines" sounds like a lot.  I haven't heard of any.

=============================================

The following is the only info my research could find, and it sounds like a problem 30 years ago with the XC II oil that is no longer produced:

parksjm wrote:Does anyone remember what was the problem with Phillips XC II 20w50 oil? The new Phillips is just XC with no "II".
I quit using it because of some controversy back in the 80's, now I don't recall what it was about. Is it safe to use, or is there still a problem with it?
Thanks,
JP



We had a Philips distributor contract back in the 80's when this issue occurred. Phillips recalled all of the XCII oil as it had been as I recall blended out of an oil base that had a lot of Sulfur in it, However what ever it was, it caused our rental airplanes to have problems with the valves sticking almost every 100 hours so that we got real adept at reaming the valve guides per the Lycoming Service bulletin. Shortly after that was when the recall occurred and we stopped using it.

Anecdotally the person who ordered and managed our oil at that time never got our stock of XCII sent in to Phillips within the recall moratorium date and we ended up stuck with about 100 cases of Phillips XCII 20W 50 in our stock room. Phillips would not take it back. So we tried using one quart in every oil change. That did not work either, soon after we started using just one quart in an oil change we started having the valve sticking problem again. After changing to Aero Shell single weight oils we never had that valve sticking problem on a regular occurring basis after that. We also when the price was right went back to using Phillips XC 20W 50 (the current product) some years latter when a different distributor offered us better pricing than we were getting with the Aero Shell. As a courtesy they took back all of the original XCII 20 W 50 oil stock we had remaining. Which were still around 100 cases.

I would say that a good ½ of my customers used XC 20W 50 (current) after that with no problem. I have never had a problem using it. 

We also got Balled up in the Mobil One synthetic oil issue and several customers that had insisted on using that ended up having to have their engines replaced, Repaired and props overhauled or flushed.

A&P, IA, New owner C170A N1208D, Have rebuilt some 50 aircraft. So many airplanes, So little time!
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