Aircooled VW Oil

[BillWilson]

John,
I have not ruled out aviation oils. Many of the VW conversion operators use automotive oils and the engine distributors recommend automotive oils. I asked an oil engineer for a major oil company and he did not want to touch my question about automotive oil use in aviation. The experimental application of this engine allows the use of non FAA approved oils. With the new techonology available, my hopes were to find the best oil for this application either FAA approved or automotive. I ran 15W50 Aeroshell in my last airplane and it worked well in a 0-200 Continental engine. Since the VW is automotive, I was not sure that FAA approved oils were the best oils for this engine. I always preheat below 30F before starting and fly an airplane at least once a week to get the engine & oil up to normal operation temps. The deposits is a real issue to consider because this engine will now be operated at fixed RPM compared to an automotive application.
Thanks for your comments,

 

[mechtech2]

One big difference in using a VW engine in a aircraft vs. a car is the airflow.
It is much better in the aircraft, cooling wise.
You won't need as thick an oil as in a car.
You will pick up a bit of power and fuel economy with the 10-30 vs. 20-50. Thin oils cool better, as well.
Other guys who use heavier oils may not be totally informed about modern oil.

 

[Lonnie]

Is there a 2-plug modification for VW heads?

 

[Pablo]

GREAT THREAD (and I thought this would just be a thread about someone's old bug) Sorry to jump in late.

Anyhow - I am quite surprised no one has suggested one of the best, HD 10w30's on the market. Killer wear protection, excellent corrosion protection:

Amsoil ACD 10w30

 

[BillWilson]

Alanu,
I will send a PM about the plungers.
MechTech,
On the VW application in the CX4 we still use an oil cooler to help with oil temps. I am not sure how the airplane oil temps are compared to the auto application.
Lonnie,
You can have two plugs per cylinder and run one set off of a magneto and the other off of electronic ignition so if you lose electrics, the engine will still run.
Pablo,
Thanks for the Amsoil info. This thread is helping me learn more about the VW conversion oil needs.

 

[Master ACiD]

im not an aviation mechanic so take what i say with a grain of salt,

you are worrying too much. if this engine is only going to be used to 3600 rpm in short bursts and 3000 max sustained, any oil will do. does not matter what brand or viscosity. ya dont need fancy lifters and junk for 3000 rpm's heck thats less than my lawnmower. my lawnmower sure dont have fancy lifters.
any old vw motor can last thousands of miles and thousands of hours on nothing more than stock parts (and that includes no oil filter). i think the vw redline was 5500 rpm's or some such nonsence. 3600 rpm's is less than the original motor ran doing down freeway in a bug chassis.

all you really need is a nice quality rebuilt motor and if you want to add an oil filter, thats just gravy on top. change the oil every 25 hours? heck that thing will last a long time like that.

there isnt really anything "wrong" with a vw motor. its just that it sort of lacks in certain areas, the fact that its camshaft does not actually get pressurized oil flow. it relies on misting off the crank, which is OK at anything above a low idle. some people say you need to break in the motor a special way (usually just keep the rpm's high to keep the cam lubed). sence youre running it in an airplane, you probably dont need to worry about it sence the rpm will awalys be above idle, and even sitting there on the tarmac waiting to take off youll probably be idling above that which a normal bug car idles at.

just dont forget some nice gauges to monitor oil pressure, temp egt, fuel pressure etc etc and youll be fine.

 

[Lonnie]

The problem with the theory that this engine does not do much is that what it does do is important. But you are right. There probably are not very many wrong choices in engine oil if you use some common sense.

 

[BillWilson]

Master Acid & Lonnie,
With the racing, diesel, & automotive oil discussed in this thread, there are some excellent oils that can be used. I will be able to monitor oil pressure, oil temp, cylinder head temps, exhaust gas temps, fuel pressure, not to mention cruising @ 125MPH getting around 30MPG with a Bug engine. I passed this thread on to two other groups so they could see the discussion.
Thanks to everyone!

 

[Lonnie]

.......and you'll keep us updated?

 

[JohnBrowning]

Master Acid, the difference between over kill for the street and smart choice for aviation is simple! On the street youc an pull over on the side of the road and either get help or walk etc... You can not park an aircraft on a cloud and walking is out of the question. Lots of property damage can happen if you lose signifacant power on take-off and even at alt. you can only glide so long. their is not always a good place to put down like in a Metro area like LA for example.

Everything in aviation is done to the extreme. Even something as mundane as a toilet is engineered to crazy standards with some of the most precise weld that most people will ever see.Then you have things like shock cooling and carberator ice, oil control and fuel control under negative g's and carbonmonoxide poisining and a whole host of of things that people in car's never have to trouble themselfs with!

 

[alanu]

Bill,

Heres a link to help you full flow your engine case so that you can filter 100% of the oil.

http://huelsmann.us/bugman/FilterTech.html

You do not need to do all of the plugs. You just need to buy a full flow cover and tap the case like this picture

The thing about an aircooled is that its below the crank. It gets a constant shower of oil from the rotating assembly.

Johnbrowning, in a stock application engine theres not gonna be brutal loads that would shear the oil IMO. Stock valve springs will not have that much cam/lifter pressures. Even though the rod ratio isn't the best with a 69mm crank and 5.394 stock lenght rods it'll be fine with sideload on the piston skirts. I'd say a decent group 3 will be great for a motor like the VW engine described. Using higher end oils will be better but it all depends on the customers wallet.

Bill, I've seen some guys modifying a type1 head adding additional spark plugs. I do not see any advantage to doing such a beast since it creates more variables that can cause issues.

What kind of induction system is used for aircraft application???

As far as lifters are concerned if your using stock valve springs resurfaced OE VW lifters (used old ones) will be excellent since the hardening will be deeply penetrated in the lifter head. Alot of people have good success with resurfaced lifters on softer spring pressures. The CB performance lightweight lifters are having excellent success with no pitting issues.

What kind of cam duration is in that engine kit? mild ramp cams will be easier on the valve train.

 

[BillWilson]

John,
General Aviation technology moves forward slowly operating on proven techniques. As you know, many of the certified piston engines operate with two magnetos, up draft carb with redline set at 2750RPM due to propeller efficiency. During single engine aircraft take off, flights over populated areas, mountain regions, and flights at night (can't see landing area) pilots worry about small things. When flying over large bodys of water you can hear things (mechanical??) you did not notice when flying over land. Thanks for your comments.
Lonnie, I will start making progress reports on my website.
Alanu, Thanks for the oil filter installation link. I am comparing it to my engine distributor oil filter installation. The cam is ground for maximum torque between 3200 & 3600 RPM. I looked at the engine info and the cam this morning, but do not have additional specs at this time. My heads are set up for single spark plugs fired by a magneto. My final decision has not been made about dual ignition. The induction system will be ram air to the updraft carb, with carb heat controlled for ice, and a tube/hose system from the carb to intake.
After I build in all of the above safety measures, I also have great info for my motor oil to be used from this group.
Thanks to all,

 

[mechtech2]

The oil cooler is and rather a must have piece, for sure.
I was referring to the high speed rather constant airflow over the cylinders and heads.

 

[Rick_A]

Bill,

I also posted this in the Aviation section but it looks like all of the activity is in this forum.
I built up an 1835cc conversion to use in my Evans VP1 (Volksplane). I have used some type of Valvoline 30 wt oil since I built it. I started out with 10W30 and eventually changed to straight 30Wt Valvoline racing oil. I have had good luck with 30 wt oils in the VP1 and my off-road cars.
I have also had good results using Delo 15W40 in my turbocharged off-road car (also vw engine). Unfortunately I didn't do any oil tests.
The VP1 engine case has be tapped for a full flow oil filter and I use an automotive filter mounted on the firewall. I originally had a stock VW oil cooler mounted on top of the engine but later changed to a larger cooler mounted on the belly of the plane. I should have stayed with the original cooler. I was seeing oil temps up to 220 degrees here in Calif. on warm days. Now it's hard to get the oil up to 180 which I feel is too low.
I run a single mag and updraft Carb. Using an Ivo prop so that I could fine tune my RPM. Normal cruise is 2800-3000 RPM. Somewhere around 200 hrs on it now with no major problems. Also got most of my engine parts from Great Plains

Good luck with your project,
Rick

 

[ctrcbob]

Ditto to what JohnBrowning said.

Although I do not have an aircraft, I remember in the past when guys would inquire about using Aircraft Oil in there cars, thinking that it was better than Automotive Oil. The answer back then was that because Aircraft engines run at one steady speed for hours at a time, they don't burn off the deposits that are left. Car engines run at various speeds, so any deposits that form are burned off at the next stop light. This may not be exactly correct, but you get the drift.

 

[kd5byb]

Quote:

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Although I do not have an aircraft, I remember in the past when guys would inquire about using Aircraft Oil in there cars, thinking that it was better than Automotive Oil.

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There is a story going around my work (we test T700 and T55 gas turbine engines) where someone swiped a case of fully synthetic MIL-PRF-23699 (military turbine engine oil) for use in their car, thinking it was "better." Apparently, the engine didn't last a week!

Gas turbine oil doesn't have the detergents that auto oils do and if I remember correctly, they don't have the EP additives of automotive oil either. I can't decide if or not a turboshaft engine needs EP additives, as the power turbine and gas generator spools are all ball-bearing supported and wouldn't require EP additives. Heck, we have 20,900 RPM bearings in our facility lubricated with plain oil DTE68 mineral oil and they last forever. But, in a turboshaft engine, the gearboxes obviously have gears, which I think would benefit from EP additives. Yet, I've never seen anything near abnormal wear in a T700 gearbox, even on old, about-to-die engines. I will admit I've never seen a T55 torn down so I can't comment on those gearboxes.

But, for sure, don't put Mobil Jet Oil II or other MIL-PRF-23699 turbine engine oil in your car...

later,
b

 

[BillWilson]

Rick,
Thanks for the feedback on your experience. I will use 30W for break in and I am considering feed back from everyone on oil to use, once the engine is broken in.
Bob,
The comments from John has me thinking about deposits. Would the Rotella T 15W40 oil help prevent deposits or do you think the aviation oils would be better for this?
kd5byb,
I retired from a large railroad and we ran military surplus jet engines on "Jet Snow Blowers". We spun them up to start RPM with a hydraulic motor and started them with 10 psi of acetylene through a nozzle and ignitor. We removed the old electrical ignitors, because we had problems lighting them below 0F with the original military system. I would never dream of using turbine oil in any thing but turbines.
Thanks for the input from everyone. This thread has been very helpful to me and I hope others!