Siezed low-time neglected turbocharger

[Area 51%]

I get through anecdotal discussion (not real-world knowledge) why the full synthetics should not be used, due to their incompatibility with 100LL. But can someone explain why the major oils used in certified aircraft are not used or considered for the VW?

[Stogie6]

Top of my head quick answer would be auto based engine vs. “aircraft” engine? I very well could be wrong since I am learning to be a gear head with my Aerovee.
Happy New Year and Happy flying!

[Onex107]

Hey Bret, glad to hear you are hanging in there. I'm not a turbo owner but am an observer of Bill Larson's turbo problem and rebuild. It is a disheartening problem. I'm not convinced the oil system is doing the job. I'll list my reasons:
1. When you stop the engine the oil flow stops? Cessna turbos have check valves before and after the turbo housing to stop the oil flow both forward and back when the pressure drops.
2. How can the return oil pump empty the pump housing when there is no air inlet to the system?
3. If temperature in the housing is the problem, why don't you know what that temp. is? A cht probe on the housing makes cense. Does the housing ever get below the critical temp of the oil? The egt is not enough.

Things to consider. Please take what I'm thinking with a grain of salt. I'm not a turbo engineer. But I think these are logical questions.
1. Water cooling. I once owned an English Ford that was water cooled but did not have a water pump. Only convection flow to the radiator.
2. Knowing the temp of the turbo housing a electric oil pump could continue to cool after the engine is stopped. If temp is the only problem?
3. Assuming the oil return pump volume exceeds the input volume, add a drain sump large enough to take all the oil that might flow after engine shut down, and add a check valve to the top of the tank that will let air in so the tank can be pumped dry. I don't understand how they think all the oil is pumped out when there is no air inlet to the system. The vacuum created would pull oil into the housing.

These are just crazy thoughts that bother me about this oil system. The term "experimental" is license to learn. Isn't it great?

[Gordon]

Rottela T4 Oil...........

I took note of your point Dale, that you use the Rottela T4 oil. This is meant for diesel engines......it is what I use in my Chevy Silverado (Duramax diesel).

I bought my VW engine from Scott Casler in Arizona, it is the Hummel 2400 85 hp, and he highly recommends using an oil meant for diesel engines like Rottela T4. It is meant for severe use and heat.

Sonex says DON'T use oil meant for diesel engines.............go figure. I plan to follow my engine builders (Scott Casler) recommendations.

On engine choices..........it is really too bad when Sonex did a re-design (the B model) they didn't go just a bit farther and design it to handle a little more weigh so we could use an 0-200 Continental or an 0-235 Lycoming.
That's what occurred in the Kitfox evolution. That also would help the re-sale values of these airplanes later down the road. In regard to weight......the 3300 Corvair must be almost the same weight as the 0-235 or 0-200. I wonder is anybody trying that in a Sonex.....?.....this would be a very interesting project.

The Panther from Florida used the Corvair engine in their first prototype with great success as I understand......but they had enough vision looking into the future that they wanted to accommodate all the builders that MUST have a Lycoming up front to feel "comfortable". Smart decision I should think.

I mention this because I was "on the fence" and about to pull the trigger on a Panther when a "pre-owned Onex" kit became available locally so I made a left turn and bought it. With all this controversy with VW engines regarding high CHTs, oil leaks, etc, etc and occasional dead stick landings I am feeling a little bit of "buyers remorse".

Gordon......Onex.....Hummel 2400

[Bryan Cotton]

I have been trying to look at ways of water cooling it but weight and complexity always brings me back to a more suitable turbo model

I am not a turbo owner. Could the oil be routed from the bearings through the water cooling passage before it returns to the sump? Or, one flow path through the bearings and one through the coolant passage? Oil is great for heat transfer and then you don't need another pump.

[daleandee]

Rottela T4 Oil...........

I took note of your point Dale, that you use the Rottela T4 oil. This is meant for diesel engines......it is what I use in my Chevy Silverado (Duramax diesel).

I bought my VW engine from Scott Casler in Arizona, it is the Hummel 2400 85 hp, and he highly recommends using an oil meant for diesel engines like Rottela T4. It is meant for severe use and heat.

Sonex says DON'T use oil meant for diesel engines.............go figure. I plan to follow my engine builders (Scott Casler) recommendations.

In regard to weight......the 3300 Corvair must be almost the same weight as the 0-235 or 0-200. I wonder is anybody trying that in a Sonex.....?.....this would be a very interesting project.

I mention this because I was "on the fence" and about to pull the trigger on a Panther when a "pre-owned Onex" kit became available locally so I made a left turn and bought it. With all this controversy with VW engines regarding high CHTs, oil leaks, etc, etc and occasional dead stick landings I am feeling a little bit of "buyers remorse".

Gordon,

I know a good many bike riders that use Rotella Conventional oil in their air cooled engines with great success. I did in mine and it proved to be an excellent choice. I use it in the Corvair & my VW bug. I also plan to use it in my Z-turn after the break-in period is over. It is the best oil I have found for air cooled engines with flat tappets. There is an excellent video about the protection Rotella gives to engines. They tore down a 500K mile truck engine and the results were quite amazing. William Wynne & Dan Weseman have studied this oil in flight engines for many years and can also attest to its breakdown resistance to high heat and it's anti-wear properties. But I digress.

The weight of my 3.0 is listed at 218 lbs which is a bit less than an O-200. The 3300 is even less than this because of more material being removed for larger cylinders and the newer stroker crank is lighter. I don't care to get into a spitting contest over it, but looking at some of the turbo installs with the extra pipes, pipe wrapping, oil lines, additional oil pump, and all the other "little add-ons" that are needed for the complete turbo install, I have to doubt that the FWF weight is still within the published specs given by the company ... but admittedly that's just a guess.

While the VW conversion I had on my nose roller was an OK engine it wasn't enough power for two up and worked hard on days with higher OATs. I would think that a Casler 2400 engine in a single place would be adequate but the fact remains that VW conversions are difficult to cool when asked to work hard.

I do like Dan's Panther but I don't need a single place airplane. If I build again, and he has the Cougar available, it would be high on the list!

Dale Williams
N319WF @ 6J2
Myunn - "daughter of Cleanex"
120 HP - 3.0 Corvair
Tail Wheel - Center Stick
Signature Finish 2200 Paint Job
166.7 hours / Status - Flying
Member # 109 - Florida Sonex Association

[Onex107]

Check out this turbo web site and the info on bearing lube. It supports several of my concerns about the Sonex installation. Things I learned: The sleeve bearings also rotate in the housing at about half the speed of the shaft and act as dampeners for the out of balance harmonics that are generated. I know turbos are balanced at harmonic rpm's, not just at the maximum. And, the "piston ring" does not rotate in the housing and just acts as a labyrinth seal.
In the info at this web site you get an oil pressure inlet number. They say that diesel egt is not as hot as automotive egt. They say that the oil drain must enter the engine above the oil level in the crankcase (gravity drain?). That would mean the turbo housing is empty all the time. They also say that an electric oil pump would continue to cool the turbo after the engine stops.
The closed Sonex system could mean that the turbo housing is full of oil, possibly under the pressure of the inlet pump, forcing oil past the piston ring. Or, gravity draining on the inlet side, after engine shutoff, would fill the housing and the seals aren't designed to handle that.
I think these statements from a manufacturer just point out that more testing is needed in the Sonex configuration.
I am not blaming Sonex for a bad installation. The tubo installation evolved from the position on the engine and the confines of the cowling and firewall. It has to be that way. I'm just a frustrated development engineer and never saw a problem I didn't love and I think this one can be solved with a little more information of what is really happening. Temperatures, pressures, flow design, oil chemistry, fuel used. All these numbers need to be known before the problem becomes clear.

http://www.turbos.bwauto.com/products/t ... ystem.aspx

[Rynoth]

I have been trying to look at ways of water cooling it but weight and complexity always brings me back to a more suitable turbo model

I am not a turbo owner. Could the oil be routed from the bearings through the water cooling passage before it returns to the sump? Or, one flow path through the bearings and one through the coolant passage? Oil is great for heat transfer and then you don't need another pump.

Physically yes, there wouldn't be nothing stopping you from adding a few hoses and adapters to additionally route the oil through the liquid cooling ports, but it would raise a a slew of additional questions, i.e. is oil psi suitable for liquid cooling ports? Will the added restriction further raise oil psi inside the housing of the turbo, how will it affect drainage, etc.

[Gordon]

Other Engine Options..........?

Further to your point Dale.......regarding engine weights and the Corvair 3 liter at 218 lbs.

If you Google the Lycoming 0-233 which is the lightweight version of the 0-235, I was surprised to see it weighs in at 213 lbs, has CDI ignition , 115 hp and TBO of 2400 hours. I then Googled the Continental 0-200-D4B (which is their lightweight version) and it came in at 199 lbs............who knew......?

I realize these are pricey engines however they are not much different in price than the Rotax 912 and the UL Power. Maybe it is time to "re-think" the engine dilemma.....of course the other obstacle besides price is the engine mount and the cowl.

More food for thought.............

Gordon..........Onex........Hummel 2400

[tljones42]

Top of my head quick answer would be auto based engine vs. “aircraft” engine? I very well could be wrong since I am learning to be a gear head with my Aerovee.
Happy New Year and Happy flying!

David,
What kind of climb rates are you getting with your non-turbo Aerovee?
Tom Jones