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Time between oil changes with a turbo?


hubcap

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hc,

Before the cavalry arrives...

What has been done for your plane through its history?

It is recorded in your log books...

Sometimes you want to take this into consideration before changing to anything different...

 

Oil is the life-blood of your expensive engine...

Filters and oil are pretty low cost in comparison...

Do you change your own oil?

PP thoughts only...

Best regards,

-a-

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I do not change my own oil. The previous owner changed the oil every 50 hours. I am not worried about saving money on oil changes. I am more concerned about saving money on less frequent engine overhauls. It is my understanding that the turbo is harder on oil, due to the heat, than a NA engine.

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50hrs is good...

Engine oil is used to cool some of the hottest parts of the engine...

Like the area around exhaust valves...   nothing hotter than these areas...  and oil doesn’t like heat...

There is a boatload of oil going to the turbo for cooling bearings there as well...

The turbo is probably slightly hotter than exhaust valves when running ROP...

Its a great topic of discussion...

 

For additional reading... there are discussions regarding turbo cooling and OWTs to be aware of...

Best regards,

-a-

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Mike Bush from savvy aviation has some good you tube videos on turbo engines and oil recommendations. Seems with our turbo engines heat is not the main concern as is contamination. I. E. We change our oil at 50 hours more due to the blow by that has acids carbon and water than due to oil breakdown due to heat. 

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The biggest problem on a turbo in any engine is shaft coking. For that reason, I believe that a semi-synthetic like Aeroshell 15W-50 is highly desirable. Personally on aircraft engines I change the oil 50 hours or 3 months, whichever occurs first. On aircraft engines, you cannot change the oil too much.

 

 

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21 hours ago, hubcap said:

I do not change my own oil. The previous owner changed the oil every 50 hours. I am not worried about saving money on oil changes. I am more concerned about saving money on less frequent engine overhauls. It is my understanding that the turbo is harder on oil, due to the heat, than a NA engine.

Having a turbocharged airplane has no effect on oil usage.

25 hours or 3 months, whichever comes first if you’ve flown mainly short trips in that period.

30 hours or 3 months, whichever comes first if you’ve flown mainly longer trips in that period.

In both cases, the oil and filter are changed.  I say this because some people will skimp and re-use a filter...sadly-enough.

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Earliest convenience after topping 25 hours or four months, whichever comes first. Phillips XC20/50 all year around in my mild, four season climate. There is some evidence that Aeroshell 15/50 is not good for Continental starter/adapters.

 

—Paul

 

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In my 231 I start thinking about it at 25 hours and make sure it’s done by 50 hours.  I’ll change it closer to 25 if the calendar time is higher than normal. 
 

I run Aeroshell 15w50 all year round in SC and I’m at almost 1600SMOH with the original cylinders so it seems to work for me (and the previous two owners who did the same). 
 

 

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We change oil not because it’s broken down, but because it’s contaminated with fuel, carbon and lead.

245 degrees is a joke for modern oil, average car’s oil temp is 220 or so if driven normally and as high as 300 on a track day. OIl is cooled on my wife’s CTS-V by engine coolant that’s 195 degrees, you don’t get much cooling until oil is well above 200. We aren’t stressing a good oil.

‘The older an engine is, the more frequently it’s oil ought to be changed, the reason is increased blow by contaminates the oil faster., unfortunately it’s new engines that people will baby with frequent oil changes, and the old ones get ignored.

‘Oil is as good as its going to get the moment it leaves the bottle, from there it’s degrading, you decide how degraded it gets before you change it.

‘I’m normally against oil analysis, as it’s marketed as and people want to believe it’s an engine analysis. However this is what oil analysis is good for, what it was created for, determining the condition of the oil. So send in a sample at your oil change interval the book recommends, and based on that analysis determine if you should shorten oil change interval.

‘Don’t use analysis to extend oil change intervals, many do, but it’s not worth it in my opinion.

I can’t make a case for running straight weight oil in one of our engines, maybe in a C-65 that loses oil pressure on a hot Summer day, but not a more modern high compression engine, even in Florida I think a good multi viscosity oil is better.

Edited by A64Pilot
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  • 4 weeks later...

I’m in the 30ish hour /3 month range. For turbo engines, one benefit of more frequent oil changes is more frequent opportunities to get eyes on your exhaust system. Know the weak spots (V band clamps in the bravo and transition in the TN).

Old oil won’t turn your plane into a Roman candle. A failed exhaust can.
-Dan

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As the old saying goes, the answer to any technical question is "it depends". How often you fly is probably the most important factor. If you want the opinion of someone (A&P/IA) who knows more about engines than most A&P's, you might want to read this article:

https://www.avweb.com/ownership/the-savvy-aviator-52-thinking-about-oil-changes/#:~:text=As a rule-of-thumb,proportionately reduced oil-change interval.

Note that it's an oldis article, and he has since changed his opinion on oil additives, but as far as I'm aware all the other advice is current. I've been adding CamGuard to my oil for at least 4 years as a consequence. So far, so good!

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Expected consequences of aging oil....

1) the more hours on the oil...

2) the more time on the oil...

3) the more byproducts of burnt fuel will get into the oil...

4) the more temperature history the oil will have...

5) acids build up in the oil, breaking down their long chains...

6) protective additives in the oil get used up...

7) Other issue...  if not used often, moisture doesn’t get driven out....


Message to the OP...  (DRJ).
 

Post pics when able...

We haven’t seen much from Sweden!   :)
 

Go MS!

Best regards,

-a-

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4 hours ago, carusoam said:

We haven’t seen much from Sweden!   :)
 

 

Nothing to see yet :-) Looking at buying that M20M and trying to understand the finer details of maintenance and what to look extra hard at for the pre buy.. Promise to post some pictures later (if everything goes according to plan)

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