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Turbo driver oil poll


Retz

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Our family owned a 414 several years ago and we never had trouble using 100W. We sold half to another individual who insisted on using 15w-50 and it has had three turbos replaced in the last ten years. Not a scientific study but good enough for me.

 

When you look at data for the 15w-50 the chart stops before you get to the temperatures it can see in a turbo bearing. I don't know if they have a good idea on how the synthetic component reacts to those high temps.

 

My 231 lives in a heated hangar so I have never considered using multi-grade yet.

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From RAM Aircraft Engines website:

 

Single Viscosity - Mineral Based AD Oil
RAM recommends Single Viscosity Mineral Based (AD) Oils such as: Aeroshell W100 and W100 Plus Antiwear (SAE 50 wt.) when typical ground level engine starting temperatures are not less than 40° F. When operating in colder enviroments Aeroshell W80 or W80 Plus Antiwear (SAE 40 wt.) and, of course preheating is recommended. [RAM service history records indicate that Mineral Based AD oils perform significantly better than synthetic and semi-synthetic oils.]

 

Multi-Viscosity - Mineral Based AD Oil
Differing operating conditions and / or availability may warrant the use of multi-viscosity oils. Most important to RAM is that the oil be mineral based. RAM recommends a multi-viscosity ashless dispersant mineral based oil such as Phillips 66 X/C 20W-50. [RAM service history records indicate that Mineral Based AD oils perform significantly better than synthetic and semi-synthetic oils.]

 

Synthetic and Semi-Synthetic Oil vs. Mineral Based Oil

RAM service history records are much less favorable for engines that have a history of
being operated on synthetic blends or semi-synthetic oil products. RAM encourages using
Mineral Based (AD) Oils only, single or multi-viscosity as conditions require.

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I use Phillips 66 X/C 20W-50 Multi-Viscosity oil as it was recommended to me by Bruce Jaeger who used to have an MSC for a long time and did an amazing job with my interiror redo.

 

After doing some reading arround, I have found that most would say that Single viscosity is fine if you are not going very high, but if you are going up to flight levels, general opinion or somewhat conscensus is that multi-viscosity behaves better.

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I use Phillips 66 X/C 20W-50 Multi-Viscosity oil as it was recommended to me by Bruce Jaeger who used to have an MSC for a long time and did an amazing job with my interiror redo.

 

After doing some reading arround, I have found that most would say that Single viscosity is fine if you are not going very high, but if you are going up to flight levels, general opinion or somewhat conscensus is that multi-viscosity behaves better.

 

yeah, oil cooler issues with potential for gelling in flight levels...supposedly. 20W-50 has never let down so far.

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FWIW, your engine manufacturer would disagree if it matters. Their recommendation is in your POH.  Specifically for Continentals it depends on whether your engine has a Hydraulic Controller like the MB and SB variants. The 231's GB and LB do not and this would not apply to the Merlyn either since its a pneumatic controller. But the Hydraulic controllers use oil pressure to control the hydraulic wategate and it is very sensitive to oil temperature. For example, max boost will vary with oil temperature which is why its common to see some overboost on the first takeoff of the day when oil temperature has not gotten up to 180F yet, and when oil temperature is really hot 200+ you won't be able to see max boost MAP (on a properly adjusted controller) because of the effect of temperature on the controller. As the oil gets hotter its viscosity reduces and this affects your controllers ability to maintain a set MAP under varying temperatures. Therefore in addition to picking an oil weight based on ambient temperatures, for Continental for turbo engines with hydraulic controllers and wategates like the TSIO-MB & SB, you will see your POH calls for a multi-weight oil to improve controller performance.

 

Personally I believe turbo shaft coking is more correlated to turbo longevity and the popular wisdom is that synthetic oils are prone to coking more than non-synthetic. Plus even RAM recommends that at annual the oil lines be removed from the turbo to flush it with solvent to clean any coking for turbo longevity.

 

I'll add in contrast, specifically for Continental engines, that starter adapters have been shown to last longer on straight weight oils. They tend to slip a bit earlier with multi-weight oils. Proof of this can be seen by switching from a multi-weight to a single weight oil at the first signs of slippage in order to get some more time out of your starter adapter -  if done soon enough.

 

Anyway I just thought I would add Continentals guidance to the discussion since it stems directly to the turbo aspect of the OP question and since its not all about ambient temperatures.

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I use Aeroshell W100+.  And I have no issues with it at the flight levels.  --Although the last time I was at FL190, the temperature was 28F, which means I didn't have the interior heater on.  I have no proven reason why I use this oil. However CHT's of 380+ are common in a 231, and for hours at a time.  It just seems like a strait weight oil would be better.  And my winter experience is the engine still gets hot. 

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Total Aero DM 15W-50, with one bottle of Camguard added to a 20litre (~5 USG) drum for me.

http://204.92.52.209/lubricants/pdf/E27_LUBRICATION_SOLUTIONS_2014-05_EN.pdf

 

15W-50 as by the Mooney manual it is that or 20W-50, although the Lycoming spec (that covers all engines -http://www.lycoming.com/Portals/0/techpublications/serviceinstructions/SI%201014M%20(05-22-1995)/Lubricating%20Oil%20Recommendations.pdf ) allows a monograde, and Total as that is easily obtainable here, Camgaurd as sometimes it happens I don't get to fly for a month and I value my camshaft! Three or four oil changes per year, always with a new filter and cut open the last, and usually with oil analysis. Strainer screen is a job for my A&P at annual.

 

Being a frequent visitor to FL180+, and using the aircraft all year, it simplifies life having one oil that can cope with +45C on the ground to -45 in the air without issues. It also makes it easier to top up in the winter when the monogrades can be like jello

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I use AS 15/50 - because that's what has been used in my plane for many years. Mark at Top Gun said that AS 15/50 is a fine oil for the Bravo engine. We don't get really cold temps in northern California - in winter is gets down to the high 20's at night - so I don't think I really need a multigrade oil. But my oil analysis has been fine and I change the oil every 25 hours.

When I had my J I used AS 100W. A friend gave me 4 quarts of AS 100 Plus. After using 2 quarts of the plus, my oil consumption went from 1 qt in 6 hours to 1 qt in 3 hours. I gave the other 2 quarts to someone else, went back to the 100W and my oil consumption went back to 1 qt in 6 hours. I'm not sure why the AS 100 Plus would cause higher oil consumption - anyone have any ideas?

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I use Phillips XC. I seriously doubt that it matters what weight you use in the flight levels. Once you are that high the engine is thoroughly warm and the air is not very good at cooling. I usually see slightly higher oil temps up high than down low. I have been in temps as cold as -55 dF in the flight levels and the oil temp is just fine. Heck, the plane was going so fast with the 100 mph tailwind that the friction from the speed over the ground was probably keeping the oil warm. Seriously, I have never seen an oil temp problem up high.

Down low is where the issue would be. I have experienced unacceptably low oil temps in the 3000-4000 foot range right after takeoff. The minimum oil temp I recall from the POH is 100, and I have been in circumstances where it hovers right at 97-101 and won't warm up in an hour's flight. Have to use an oil cooler block here in the winter to prevent that, it would not make much difference what oil you used although I would not want to be flying with a single weight 100 in those temps.

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Down low is where the issue would be. I have experienced unacceptably low oil temps in the 3000-4000 foot range right after takeoff. The minimum oil temp I recall from the POH is 100, and I have been in circumstances where it hovers right at 97-101 and won't warm up in an hour's flight. .

 

My recent engine temperatures have been hovering at 85-105F for extended periods.  Several days in fact.   This is of course before I start the engine.  So I am reasonably happy to use mono-weight. I'd feel different if I lived in a colder climate.  And I am religious about using my electric pre-heater when I visit colder climates.   

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I encourage people to watch the Busch video. The issue isn't so much multi-grade versus straight as it is synthetic versus oil. It is a really interesting presentation and has some good facts in it. I once asked a guy in Texas who gets cited a lot when it comes to Mooney's he wasn't a big fan of the synthetics (Aeroshell I particular).

The biggest thing I find useful is changing it 4 times a year (once every three months) versus what I put in it but I still use the Philips. I have seen some oil analysis posted here where people go 7 months or more on the same oil which just isn't good.

For the record no heat issues using 100W Plus or Philips in the Fl's with a Rayjay. I would suspect some of the hot issues people are seeing come from climbing too steep or bad baffling more than the oil.

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