Oil for diesel engine in aircraft

[JohnTDI]

Guys (and girls too),

Here's the situation: a friend and I are building a Vans RV-7A, we plan on installing a diesel engine in this aircraft and we're looking for the best oil we can get for this application.
Our objectives are reliability and long life first then fuel consumption.

This engine is a 4 cylinder, inverted, indirect injection, turbo and supercharged 2 stroke diesel. Max rpm is 2700 and power is 160bhp.
There will be a hydraulic constant speed propeller on the nose.

So far I'v been reading the forums and personally I would give schaeffers 7000 15W40 a good change of been the best we can get for this. But can we get schaeffers in or shipped to Europe? We would not mind getting a barrel of oil here. If we can not get schaeffers to Europe, I was thinking of a Mobil Delvac 1 SHC 5W40 or anything like that.
Please do advise.

For oil filtration, the engine manufacturer uses purolator pure one filters. We would go with that initially and switch to a remote by-pass such as an amsoil BMK-13 setup. If we can get this here too.

Air filtration is supplied by the engine manufacturer and is a oiled foam setup. We need to stick with this due to the fact that if we would switch we need to prove with testing that the pressure drop will not exceed preset limits during the life of the filter.

All of your opinions are greatly appreciated!

John

[ March 12, 2003, 01:58 AM: Message edited by: JohnTDI ]

 

[Jimbo]

Please, more details about this engine. What is the displacement and installed mass? Who is the manufacturer and do they have a website?

For an aircraft installation, I would follow the engine manufacturers lubrication recommendations to the letter. Also, a bypass oil filter is going to take up space, add mass and have another source of possible leaks due to the lines and fittings.

Air filtration is not a big deal in most aircraft because most of the engine hours are spent far away from sources of dirt, unless you operate near an active volcano.

What a great project!

 

[JohnTDI]

Jimbo,
This is for sure an exciting project; I'm following the designer since 1999 and have met them on several occassions. I do believe that this engine is going to be a succes.
The engine is by Wilksch Airmotive from the UK, their website is www.wilksch.com
Displacement is 2400 cm3 (somewhere around 150cub inch if memory serves) and its weight is 115Kg.
Installed weight should be around 125Kg

I'v already asked them about the oil and their viscosity recommendation was 15W40. But at that time nothing more was known, they were still running JAR tests. So I started to search and learned at lot from this site (what a great place!!) about oil and lubrication.

John

[ March 13, 2003, 12:45 AM: Message edited by: JohnTDI ]

 

[AV8R]

Two-strokes may tend to be very sensitive to port deposits, which can restrict flow on both intake and exhaust sides, disproportionately to the reduction of cross sectional area, because of turbulence and vorticity port deposits create in the flow stream. The reduction of horsepower this can cause can be very dangerous in an aircraft that operates near its max gross weight. While 15W-40s may give good wear and long life, they are high-ash and more prone to deposit-forming. Most refiners make a line of monograde oils low in ash specifically for Detroit 2-strokes, which may be excellent for this engine, almost certainly better than a 15W-40. Low levels of magnesium and high levels of ZDDP and calcium would be favorable. A Champion aircraft filter would be the choice here, not so much for filtering, but for reliability in the application. An automotive filter would be very risky to use, and for say 25 hour changes, you don't need that much filtering.

 

[Doug Hillary]

Hi,
depending on what the engine manufacturers recommend, two stroke diesels will require a specific oil - usually a monograde
This is to ensure a clean burn

I think CF-2> will be a requirement but go with what the maunufacturer recommends. Castrol's two stoke diesel specific oils are excellent products

Regards

 

[AV8R]

Doug, I just took a look at the CITEC cycle diagram on the Wilksh website, I'm guessing you have already. The engine is inverted, and uses ports for intake (has to be supercharged for this) and a conventional valve for exhaust. Also uses a ball-and-socket, instead of a gudgeon pin.

So, intake ports are in the cool, away from soot, and shouldn't form much in the way of deposits. Detergents wouldn't likely see high enough temperatures in this area to activate anyway. Also, blowby should be practically nonexistent due to the ball rod end and good ring sealing of the inverted configuration, making this engine easy on oil, and the ports very insensitive oil ash content. Jet-A has lower sulfur that automotive low-sulfur diesel, easing demands more. The most critical factors may be top groove fill, and oil temperature, especially at altitude. I would hope the manufacturer tests your old favorite, D1, in this engine, as I believe it would perform very well in ring cleanliness and temperature stability .

 

[JohnTDI]

Guys, thanks for your reply. I'll be visiting Wilksch end of this month and will ask them about their oil recommendation. And also if they are willing to run it with D1, thing is that D1 si rather difficult to get here in Europe.

John