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  #1  
Old 11-18-2008, 08:39 PM
N24YW N24YW is offline
 
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Default Auto fuel why not auto oil?

I was just thinking. If I run a lot of auto fuel in my engine would it not make more sense to also run a automotive oil. I think some of the additives in Aviation are to help offset the bad effect of lead in the fuel. With 15-50 at 6.30 a quart I was wondering what would happen if I ran a 15-50 racing oil.

Jim Knight
Burlington Iowa
RV-6 350 hours
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  #2  
Old 11-18-2008, 09:18 PM
Martin Sutter Martin Sutter is offline
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Don't even think about it!!

Automotive oils are formulated for close tolerance water cooled engines. Aircraft engines are air cooled and have much larger tolerances. That makes the requirements for the lubricating oil unique to their genre.

Martin Sutter
Building and flying RV's since 1988
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  #3  
Old 11-18-2008, 10:30 PM
asav8tor asav8tor is offline
 
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Many of the auto oils are better at reducing friction but can't handle the lead. Since you are using unleaded that problem would not be a problem. The second issue is many of the friction reducers will form ash deposits as the air cooled engine is designed to burn some oil. That problem will be a problem and it can be a big problem. Don't do it.
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  #4  
Old 11-18-2008, 11:17 PM
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N941WR N941WR is offline
 
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I seem to remember reading an article which stated that the additives in automotive oils are corrosive to the metals used in aircraft engines.

However, in the quick search I performed, I couldn't find any reference to that.

Mel, Mahlon - comments?
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  #5  
Old 11-19-2008, 05:53 AM
1flyer 1flyer is offline
 
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Quote:
Originally Posted by Martin Sutter View Post
Automotive oils are formulated for close tolerance water cooled engines.
I know a lot of motorcycle owners that would disagree with you. Lots of VW bug owners would also be happy to join with them.
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  #6  
Old 11-19-2008, 06:25 AM
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While I am completely ignorant on aircraft air-cooled engines, my Porsche 914 engine (also air-cooled 4-banger) had no issues with regular automotive oil.

Quote:
Originally Posted by 1flyer View Post
I know a lot of motorcycle owners that would disagree with you. Lots of VW bug owners would also be happy to join with them.
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  #7  
Old 11-19-2008, 06:55 AM
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carguy614 carguy614 is offline
 
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Default AD oil

Aircraft engine lubricants contain special additive packages to handle the lead intrusion as well as a dispersant to suspend the ash deposits. Clearly automotive lubricants, although very advanced these days, do not meet these special requirements. Best to use the recommended lubricants in your engine.

Regards,
Chris
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  #8  
Old 11-19-2008, 09:16 AM
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Veetail88 Veetail88 is offline
 
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Default Why take a chance for so little gain?

I'm not an oil expert, but it seems to me that at best, the issue of using auto oil is contraversial and at worst, dangerous and possibly expensive.

Why would you want to risk a very expensive motor and possibly your life to save a few bucks on oil.

Makes no sense to me....


Jesse Bentley
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Muskego, WI
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  #9  
Old 11-19-2008, 10:26 AM
Tomasz Tomasz is offline
 
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Quote:
Originally Posted by Veetail88 View Post
Why would you want to risk a very expensive motor and possibly your life to save a few bucks on oil.
Because everyone asks the question - is aviation oil more expensive because it's different and more expensive to produce, or is it just because it can?

I'm neither an oil expert nor I suggest using auto fuel in your bird, but sometimes I have that feeling that we, pilots and owners are treated by manufacturers as 'rich boys club' and many things cost.

And to make things worse:
If auto fuel than what grade/class? diesel/gas? synthetic/mineral/blended? branded/store branded? etc...

This topic can get even hotter than the one about leaning :-)
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  #10  
Old 11-19-2008, 10:43 AM
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f1rocket f1rocket is offline
 
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This topic has been hammered about as many times as the topic of whether to prime aluminum or not.

Lycoming, AvWeb, and others have articles about the differences in auto oil and aviation oil. Last time I researched the topic, they seemed to make sense to me so I stuck with aviation oil. As I recall, they are different and there are some important reasons for that. I went to the Lycoming site to see if I could find the articles but they recently reorged their site and I couldn't find it quickly.

It's a good, valid question. You'll either believe the answers or not. In this case I don't believe it is a case of overcharging because they can, but I'd love to be proven wrong on that!

Check out this thread: http://www.vansairforce.com/communit...light=auto+oil
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Last edited by f1rocket : 11-19-2008 at 10:53 AM.
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