Has anyone used auto fuel in an IO system ? I will be building the RV-9 and wanted to use the 150HP IO-320 (ECI engine probably). I was told by a distributer rep for the ECI engine that auto fuel (like 93 octane) did not work well with the injected system. Something to do with the servos....They recommended go with the 100LL or use a carb. system (if auto fuel was a must). Is this common knowledge to all but myself ? I would appreciate any input or first hand advice on this.
Van's Air Force
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Auto fuel in IO-320 ?
- Thread starter sfrench
- Start date
frankh
Well Known Member
Nonsense!
Autoful works VERY well indeed in a FI's engine, and runs ROP or LOP just like 100LL.
Now a qualification....Most autofuel has ethanol in it. Now ethanol runs perfectly well in an IO engine BUT the mechanical fuel pump diaphram is not immune to degradation by the ethanol.
I don't use a mechanical pump partly for that reason. Similarly, for your particular FI servo and hoses you will need to determine if the seals will withstand ethanol.
Flourosilicone seals are best (usually blue) , viton(brown) are the next best.
Teflon lined fuel hoses are perfect.
The fuel drain rubbers will degrade but flourosilicone ones are available from mcmaster Carr.
There is rumour that dissolved water will drop out of suspension in ethanol laced fuel at altitude/low temp..Personally at 15.5k and well below freezing I have not had a problem.
Frank IO 360
Autoful works VERY well indeed in a FI's engine, and runs ROP or LOP just like 100LL.
Now a qualification....Most autofuel has ethanol in it. Now ethanol runs perfectly well in an IO engine BUT the mechanical fuel pump diaphram is not immune to degradation by the ethanol.
I don't use a mechanical pump partly for that reason. Similarly, for your particular FI servo and hoses you will need to determine if the seals will withstand ethanol.
Flourosilicone seals are best (usually blue) , viton(brown) are the next best.
Teflon lined fuel hoses are perfect.
The fuel drain rubbers will degrade but flourosilicone ones are available from mcmaster Carr.
There is rumour that dissolved water will drop out of suspension in ethanol laced fuel at altitude/low temp..Personally at 15.5k and well below freezing I have not had a problem.
Frank IO 360
Auto fuel
10-4. Should have known alcohol was the issue. So you run an electric pump with another electric back-up ? I guess I have seen some discussions on this. Is there such a thing as a mechanical fuel pump that is alcohol tolerant, or is the duel electrical the accepted way to go ? Any other advice is well received. I'm finishing a scratch build now, and have had enough surprises for an aviation lifetime.
10-4. Should have known alcohol was the issue. So you run an electric pump with another electric back-up ? I guess I have seen some discussions on this. Is there such a thing as a mechanical fuel pump that is alcohol tolerant, or is the duel electrical the accepted way to go ? Any other advice is well received. I'm finishing a scratch build now, and have had enough surprises for an aviation lifetime.
Can't see why you couldn't just rebuild the fuel pump with the flourosilicone seals. It's not like a mechanical fuel pump is rocket science.
I've had an Edelbrock Ford style mechanical pump on my 1965 Cobra replica and have been running ethanol gas in it as long as it's been put in pumps here. I've not seen any thing in the float bowl of the carb and the pressure out of the pump is same as it was new.
As for the water precipitating out, I had my wife do some tests in her lab for me. They have -20C and -80C freezers. I had her put a fuel sample in each to see what happened. In the -20C (-4F) the fuel appeared to remain a homogeneous liquid. In the -80C (-112F WAY below what *I* would be flying in), the fuel did seperate slightly, but the real problem was that it turned to a near Jello state. So I'm not really that worried about it coming out of solution, I'm more concerned that the rubber parts will handle it.
I've had an Edelbrock Ford style mechanical pump on my 1965 Cobra replica and have been running ethanol gas in it as long as it's been put in pumps here. I've not seen any thing in the float bowl of the carb and the pressure out of the pump is same as it was new.
As for the water precipitating out, I had my wife do some tests in her lab for me. They have -20C and -80C freezers. I had her put a fuel sample in each to see what happened. In the -20C (-4F) the fuel appeared to remain a homogeneous liquid. In the -80C (-112F WAY below what *I* would be flying in), the fuel did seperate slightly, but the real problem was that it turned to a near Jello state. So I'm not really that worried about it coming out of solution, I'm more concerned that the rubber parts will handle it.
Dave is it possible your samples had fairly low quantities of water suspended in the fuel?
could you do another test where you use a known high percentage of ethanol fuel (10% or more), add as much water as you can until it will not absorb any more, and then re run the -20c test? I wonder if your sample was relatively dry and if there was a higher saturation it would precipitate out more at the low tempuratures.
frankh
Well Known Member
Yes
Well if you can find (or make) a flourosilicone diaphram then sure..Now of course the standard fuel system is less than ideal from a Vapour lock perspective but in terms of making a standard system work with ethanol thrn sbsolutly this would work.. But I have no idea how to do it.
Frank
Well if you can find (or make) a flourosilicone diaphram then sure..Now of course the standard fuel system is less than ideal from a Vapour lock perspective but in terms of making a standard system work with ethanol thrn sbsolutly this would work.. But I have no idea how to do it.
Frank
N941WR
Legacy Member
Two things.
First, auto fuel is not controlled like 100LL is. As I understand it, every tanker fill delivered to a gas station could be a different formula. Thus its ability to retain water is different.
(BTW, I've tested a lot of the pumps here in the Carolinas, even those with the sticker saying they contain ethanol, and in the last year it is rare that I find some. Most of the gas is "clean".)
As for the fuel pumps on aircraft engines. They are all made the same way due to the PMA requirements. An auto pump, although identical is probably made with material that is impervious to ethanol.
What would be the thing to is buy a rebuild kit for an auto fuel pump that matches what we have on our Lycomings and then rebuild your Lycoming pump using the new seals, diaphragm, etc.
First, auto fuel is not controlled like 100LL is. As I understand it, every tanker fill delivered to a gas station could be a different formula. Thus its ability to retain water is different.
(BTW, I've tested a lot of the pumps here in the Carolinas, even those with the sticker saying they contain ethanol, and in the last year it is rare that I find some. Most of the gas is "clean".)
As for the fuel pumps on aircraft engines. They are all made the same way due to the PMA requirements. An auto pump, although identical is probably made with material that is impervious to ethanol.
What would be the thing to is buy a rebuild kit for an auto fuel pump that matches what we have on our Lycomings and then rebuild your Lycoming pump using the new seals, diaphragm, etc.
Pedro
I'm New Here
Auto fuel and alcohol
Hi Scott and folks:
Here in Brazil we have lots of Lycoming engines converted to run 100% on alcohol. I am sure the fuel pump problem was solved.
Take a look at this article below.
"ETHANOL-FUELED IPANEMA CERTIFIED BY THE CTA"
(Ipanema is a crop duster aircraft by Embraer / Neiva manufacturer, which uses a Lycoming IO-540-K1J5, 320HP)
Check that on http://www.defesanet.com.br/embraer/neiva1/
(scroll down to the bottom to read in English)
Below is Neiva's website:
http://www.aeroneiva.com.br/site/content/home/
Pedro
RV-9A
(Inventory)
Hi Scott and folks:
Here in Brazil we have lots of Lycoming engines converted to run 100% on alcohol. I am sure the fuel pump problem was solved.
Take a look at this article below.
"ETHANOL-FUELED IPANEMA CERTIFIED BY THE CTA"
(Ipanema is a crop duster aircraft by Embraer / Neiva manufacturer, which uses a Lycoming IO-540-K1J5, 320HP)
Check that on http://www.defesanet.com.br/embraer/neiva1/
(scroll down to the bottom to read in English)
Below is Neiva's website:
http://www.aeroneiva.com.br/site/content/home/
Pedro
RV-9A
(Inventory)
comfortcat
Well Known Member
Looks like Ethanol is here to stay... in the West anyway.
Unfortunately, not in California. More and more gas pumps say "May contain up to 10% Ethanol" I believe more of the west coast is going this way, no?
Unfortunately, not in California. More and more gas pumps say "May contain up to 10% Ethanol" I believe more of the west coast is going this way, no?
I'll get my research assistant on it in short order. But for comparison, it was fuel pulled from a standard pump labeled as 10% ethanol. I know that it varies, and I'd love to buy stuff without ethanol at all, but no such pump exists within an area that I'm willing to readily get fuel from. The reason for the test was that I read somewhere that water could separate and while you may use the quick drain and not get any, it could be suspended in the fuel. I couldn't get good separation until the fuel turned to a runny jello like consistency. Flying with that would have other major implications.
I want to be clear that I'm not advocating what anyone else should do, I just figured I had the resources to run a simple little test and see what happened. I don't think a modern boost pump will be the problem, it's probably if you want to run a legacy mechanical pump that the "rubber" membranes and o-rings could be a problem (and the "rubber" fuel hose).
I've not rebuilt my fuel pump, but was planning on it just because. I'd expect any automotive rebuild kit will have newer material and just looking at the thing I'd bet it takes all the same parts inside as any early model car fuel pump.
To me this is experimental, and what it's all about. That being said, I shall be well practiced on my engine out procedures!
Pedro,
Are you saying that fuel pump diapham materials have been changed? Are these pumps available to be purchased by us in the States? Do youo have a source/cost?
Or are you saying that the stock lycolming pumps will withstand fuel with alcohol?
By the way, I was not able to get the first link to open, so did not get the English version.....
Are you saying that fuel pump diapham materials have been changed? Are these pumps available to be purchased by us in the States? Do youo have a source/cost?
Or are you saying that the stock lycolming pumps will withstand fuel with alcohol?
By the way, I was not able to get the first link to open, so did not get the English version.....
Good info posted above, but I'm not sure everyone understand that gas from a (auto) station isn't just gas.
If you live in almost any any large metro are in the US (speficially a non attainment area) you'll most likely be buying reformulated (auto) gasoline. Back in my refinery days, I believe there were were some 50 different mixes specified across the country. And then there is the seasonal variation in blends.
Point is to just make yourself familiar with this stuff. It behaves differently that pure gasoline (physical characteristics, composition, quality, etc.).
If you live in almost any any large metro are in the US (speficially a non attainment area) you'll most likely be buying reformulated (auto) gasoline. Back in my refinery days, I believe there were were some 50 different mixes specified across the country. And then there is the seasonal variation in blends.
Point is to just make yourself familiar with this stuff. It behaves differently that pure gasoline (physical characteristics, composition, quality, etc.).
David,
If you find a diaphragm that can be substituted into a Lycolming pump please let us know. I for one would love to be able to get away from the 100LL and start using auto fuels with ethanol. The rest of my fuel system is ready, but I haven't pull the conversion trigger due to the Lycolming pump diaphragm issue with ethonal....
If you find a diaphragm that can be substituted into a Lycolming pump please let us know. I for one would love to be able to get away from the 100LL and start using auto fuels with ethanol. The rest of my fuel system is ready, but I haven't pull the conversion trigger due to the Lycolming pump diaphragm issue with ethonal....
I'll get my research assistant on it in short order. But for comparison, it was fuel pulled from a standard pump labeled as 10% ethanol. I know that it varies, and I'd love to buy stuff without ethanol at all, but no such pump exists within an area that I'm willing to readily get fuel from. The reason for the test was that I read somewhere that water could separate and while you may use the quick drain and not get any, it could be suspended in the fuel. I couldn't get good separation until the fuel turned to a runny jello like consistency. Flying with that would have other major implications.
I want to be clear that I'm not advocating what anyone else should do, I just figured I had the resources to run a simple little test and see what happened. I don't think a modern boost pump will be the problem, it's probably if you want to run a legacy mechanical pump that the "rubber" membranes and o-rings could be a problem (and the "rubber" fuel hose).
I've not rebuilt my fuel pump, but was planning on it just because. I'd expect any automotive rebuild kit will have newer material and just looking at the thing I'd bet it takes all the same parts inside as any early model car fuel pump.
To me this is experimental, and what it's all about. That being said, I shall be well practiced on my engine out procedures!
Greg Arehart
Well Known Member
I agree with Fred, would love to use ethanolated fuel but the sticking point for my system also is the mechanical pump. I use autofuel in summer when there is no ethanol (and I test it every time) and have had no problems.
Please keep us posted.
greg
Please keep us posted.
greg
ethanol
Around here most gas pumps are labeled "MAY CONTAIN UP TO 10% ETHANOL".
I've tested the fuel from these pumps in the summer at around 4-5%.
I'm sure they bump it up to 10% in the winter.
I don't know how well the 4-5% stuff would work in my low compression o-320 but I'm tempted to at least test it.
Mixed with a little 100ll you'd think the % ethanol shouldn't hurt.
There's a guy at my airport with a -6 that's been using car gas for the last 14 years with no problems. He does not test the fuel but thinks its had ethanol in it for most of those years. He also has a low compression o-320.
I found a station that has no ethanol but its about 40 mi down the road.
Just another data point...
Dave
-9A FWF kit
N514R
Around here most gas pumps are labeled "MAY CONTAIN UP TO 10% ETHANOL".
I've tested the fuel from these pumps in the summer at around 4-5%.
I'm sure they bump it up to 10% in the winter.
I don't know how well the 4-5% stuff would work in my low compression o-320 but I'm tempted to at least test it.
Mixed with a little 100ll you'd think the % ethanol shouldn't hurt.
There's a guy at my airport with a -6 that's been using car gas for the last 14 years with no problems. He does not test the fuel but thinks its had ethanol in it for most of those years. He also has a low compression o-320.
I found a station that has no ethanol but its about 40 mi down the road.
Just another data point...
Dave
-9A FWF kit
N514R
Pedro
I'm New Here
Auto fuel / alcohol issues
Hi Fred. I am not aware of what engine components and accessories they changed for the Lyc. IO-540 engine to become 100% alcohol operational. I emailed them for a quote and asked what parts need to be replaced or upgraded. As soon as they answer I will post here.
Below is the article of that first link (http://www.defesanet.com.br/embraer/neiva1/) for those who could not get the access.
"The Ipanema is the first series production aircraft in the world
coming out of the factory certified for flying with ethanol
S?o Jos? dos Campos, October 19, 2004 - Ind?stria Aeron?utica Neiva, a wholly owned Embraer subsidiary, has received type certification for its ethanol-fueled Ipanema crop-dusting aircraft from Brazilian aviation regulating agency Centro T?cnico Aeroespacial (CTA). The Ipanema is the first series production aircraft in the world coming out of the factory certified for flying with ethanol.
"An efficient and cheaper source of power, the ethanol alternative will find favor with farmers for lowering their crop-dusting aircraft's operating costs" said Satoshi Yokota, Embraer Executive Vice-President for Development and Industry. "Ethanol is also a more environmentally friendly fuel and Neiva research indicates that it may prolong the engine's life, making it a prospective national market success. "In the medium and long terms, we may benefit from the introduction of the Ipanema in countries that adopt ethanol as a source of energy."
The choice for using ethanol was based on the fact Brazil is a major producer of this type of alcohol, extracted from sugar cane, and automobiles have been using this fuel for more than 20 years. This makes ethanol about three to four times cheaper than aviation gasoline (AvGas).
Additionally, ethanol-powered aircraft engines are cleaner and have lower levels of emission than AvGas because they have no lead in their composition, providing for a more environmentally friendly fuel. Neiva has registered the name "AvAlc" (Aviation Alcohol) in Brazil for use of this new fuel.
The use of an ethanol-powered engine will allow for an increase of about 5 percent in power, thus improving performance in general, namely takeoff run, climb rate, speed and maximum altitude. Initial tests showed that ethanol may also boost from 20 to 80 percent the engine's maintenance cycle.
Conversion of existing engines is not only feasible but also cost effective. Neiva received 69 orders to retrofit customers' AvGas-fueled Ipanemas into ethanol-powered airplanes. This work is expected to begin in January of the next year. Deliveries of the first units of the ethanol version are expected in the first quarter 2005.
The Ipanema is Neiva's best selling aircraft with over 30 years of uninterrupted production and nearly 1.000 units sold . This year, Neiva forecasts 82 Ipanema deliveries compared with 46 in 2003. A dominant force on the domestic Brazilian market, the company's market share is about 80 percent."
Pedro
RV-9A
(Inventory)
Brazil
Hi Fred. I am not aware of what engine components and accessories they changed for the Lyc. IO-540 engine to become 100% alcohol operational. I emailed them for a quote and asked what parts need to be replaced or upgraded. As soon as they answer I will post here.
Below is the article of that first link (http://www.defesanet.com.br/embraer/neiva1/) for those who could not get the access.
"The Ipanema is the first series production aircraft in the world
coming out of the factory certified for flying with ethanol
S?o Jos? dos Campos, October 19, 2004 - Ind?stria Aeron?utica Neiva, a wholly owned Embraer subsidiary, has received type certification for its ethanol-fueled Ipanema crop-dusting aircraft from Brazilian aviation regulating agency Centro T?cnico Aeroespacial (CTA). The Ipanema is the first series production aircraft in the world coming out of the factory certified for flying with ethanol.
"An efficient and cheaper source of power, the ethanol alternative will find favor with farmers for lowering their crop-dusting aircraft's operating costs" said Satoshi Yokota, Embraer Executive Vice-President for Development and Industry. "Ethanol is also a more environmentally friendly fuel and Neiva research indicates that it may prolong the engine's life, making it a prospective national market success. "In the medium and long terms, we may benefit from the introduction of the Ipanema in countries that adopt ethanol as a source of energy."
The choice for using ethanol was based on the fact Brazil is a major producer of this type of alcohol, extracted from sugar cane, and automobiles have been using this fuel for more than 20 years. This makes ethanol about three to four times cheaper than aviation gasoline (AvGas).
Additionally, ethanol-powered aircraft engines are cleaner and have lower levels of emission than AvGas because they have no lead in their composition, providing for a more environmentally friendly fuel. Neiva has registered the name "AvAlc" (Aviation Alcohol) in Brazil for use of this new fuel.
The use of an ethanol-powered engine will allow for an increase of about 5 percent in power, thus improving performance in general, namely takeoff run, climb rate, speed and maximum altitude. Initial tests showed that ethanol may also boost from 20 to 80 percent the engine's maintenance cycle.
Conversion of existing engines is not only feasible but also cost effective. Neiva received 69 orders to retrofit customers' AvGas-fueled Ipanemas into ethanol-powered airplanes. This work is expected to begin in January of the next year. Deliveries of the first units of the ethanol version are expected in the first quarter 2005.
The Ipanema is Neiva's best selling aircraft with over 30 years of uninterrupted production and nearly 1.000 units sold . This year, Neiva forecasts 82 Ipanema deliveries compared with 46 in 2003. A dominant force on the domestic Brazilian market, the company's market share is about 80 percent."
Pedro
RV-9A
(Inventory)
Brazil
Dave, I would be interested in how to go about testing fuel for ethanol for my own use. Could you explain how that is done? Thanks.
Greg Arehart
Well Known Member
testing for ethanol
Testing for ethanol is simple. Get yourself a tall, thin plastic or glass tube (I use a glass separatory funnel, but I have access to all sorts of lab gear) - about an inch in diameter and 6-8 inches tall (very approximate). Pour a bit of water in the bottom, maybe a half-inch or inch. Mark the water level on the side of the tube with a sharpie or similar marker. Add several inches of gasoline from the pump. Cap the tube and shake vigorously for 5 seconds to mix the water and gas. Let it settle for a minute or two so the water can separate from the gas. If the "water" is now more than when you started (i.e., above the marked line) then you have ethanol in your gasoline. If the water level stays the same, no ethanol. What happens is that ethanol is more soluble in water than in gasoline, so when you mix up the three components (water, ethanol, gasoline), the water will suck up the ethanol. You don't actually have to do the shaking bit, but if you don't shake, then it takes a while longer for the ethanol to get from the gas into the water. If you have only 1% ethanol, or some similar small number, then the shake test may not be as good as the "let it sit overnight" test. With our 8-10% ethanol, it is immediately obvious within seconds after the shake test.
I suggest that you do this on a sample where you know there is ethanol in the fuel and make sure that you see the difference before going to an unknown sample. I do this with every batch of auto fuel that I purchase, right at the gas station before filling my tanks. I neglected to do it at the station once when I was assured there was no ethanol but then did the test at home later and found that I had just purchased myself 100 gallons of premium car gas. My car liked it though!
Hope this was clear enough.
cheers,
greg
Testing for ethanol is simple. Get yourself a tall, thin plastic or glass tube (I use a glass separatory funnel, but I have access to all sorts of lab gear) - about an inch in diameter and 6-8 inches tall (very approximate). Pour a bit of water in the bottom, maybe a half-inch or inch. Mark the water level on the side of the tube with a sharpie or similar marker. Add several inches of gasoline from the pump. Cap the tube and shake vigorously for 5 seconds to mix the water and gas. Let it settle for a minute or two so the water can separate from the gas. If the "water" is now more than when you started (i.e., above the marked line) then you have ethanol in your gasoline. If the water level stays the same, no ethanol. What happens is that ethanol is more soluble in water than in gasoline, so when you mix up the three components (water, ethanol, gasoline), the water will suck up the ethanol. You don't actually have to do the shaking bit, but if you don't shake, then it takes a while longer for the ethanol to get from the gas into the water. If you have only 1% ethanol, or some similar small number, then the shake test may not be as good as the "let it sit overnight" test. With our 8-10% ethanol, it is immediately obvious within seconds after the shake test.
I suggest that you do this on a sample where you know there is ethanol in the fuel and make sure that you see the difference before going to an unknown sample. I do this with every batch of auto fuel that I purchase, right at the gas station before filling my tanks. I neglected to do it at the station once when I was assured there was no ethanol but then did the test at home later and found that I had just purchased myself 100 gallons of premium car gas. My car liked it though!
Hope this was clear enough.
cheers,
greg
EAA test kit and info
http://www.eaa.org/autofuel/autogas/test_kit.asp
link to kit EAA sells also lots of info on mogas
http://www.eaa.org/autofuel/autogas/test_kit.asp
link to kit EAA sells also lots of info on mogas
AK4x4
Well Known Member
Alcohol Issues
There are a couple of issues with auto fuel containing alcohol. Number one is that in the USA aircraft spec rubber items (hose, fuel bladders etc.) are not alcohol resistant. Alcohol will slowly break them down. For this reason Cessna says the folowing.(" WARNING: Use of alcohol-based fuels can cause serious performance degradation and fuel system component damage, and is therefore prohibited on Cessna airplanes.") The fix is to use automotive parts, hoses, etc. in constructing your fuel system. The second problem is that the air/fuel mixture ratio for gasoline is ~14/1 while alcohol is between 7/1 and 8/1. So as the alcohol content of the fuel increases your baseline mixture is becoming leaner and leaner. The fix is if you run fuel with large amounts of alcohol (~8% or greater) you need to enlarge your main metering jets to richen your overall mixture. Cars with O2 sensors and electronic fuel injection do this automaticly but aircraft carbs or mechanical fuel injection dont. So now the engine will run good (make slightly more torque with noticably higher fuel consumption) on your alcohol based fuel. HOWEVER, if you fuel with plain ol gasoline the engine will be excessivly rich and will require leaning with the mixture control before takeoff to prevent fouling and rough running. (Personally I would avoid fuel with alcohol and stick with 100LL. Really good fuel and allows me to raise the compression, advance the timing, and have lots of fun feeding my desire for more horsepower.) If you can find auto gas with very low or no alcohol and insist on using it, then I would recomend blending 4 parts low octane auto gas with 1 part 100LL. This seems to work OK on engines with 8.5-1 or lower compression and prevents valve seat recession and other undesirable wear. Higher compression engines really should stick with 100LL. Just my .02 worth. Russ AP/IA Alaska.
There are a couple of issues with auto fuel containing alcohol. Number one is that in the USA aircraft spec rubber items (hose, fuel bladders etc.) are not alcohol resistant. Alcohol will slowly break them down. For this reason Cessna says the folowing.(" WARNING: Use of alcohol-based fuels can cause serious performance degradation and fuel system component damage, and is therefore prohibited on Cessna airplanes.") The fix is to use automotive parts, hoses, etc. in constructing your fuel system. The second problem is that the air/fuel mixture ratio for gasoline is ~14/1 while alcohol is between 7/1 and 8/1. So as the alcohol content of the fuel increases your baseline mixture is becoming leaner and leaner. The fix is if you run fuel with large amounts of alcohol (~8% or greater) you need to enlarge your main metering jets to richen your overall mixture. Cars with O2 sensors and electronic fuel injection do this automaticly but aircraft carbs or mechanical fuel injection dont. So now the engine will run good (make slightly more torque with noticably higher fuel consumption) on your alcohol based fuel. HOWEVER, if you fuel with plain ol gasoline the engine will be excessivly rich and will require leaning with the mixture control before takeoff to prevent fouling and rough running. (Personally I would avoid fuel with alcohol and stick with 100LL. Really good fuel and allows me to raise the compression, advance the timing, and have lots of fun feeding my desire for more horsepower.) If you can find auto gas with very low or no alcohol and insist on using it, then I would recomend blending 4 parts low octane auto gas with 1 part 100LL. This seems to work OK on engines with 8.5-1 or lower compression and prevents valve seat recession and other undesirable wear. Higher compression engines really should stick with 100LL. Just my .02 worth. Russ AP/IA Alaska.
Greg Arehart
Well Known Member
Bruce,
This is true, all gasoline is locally blended with ethanol (I think it has been noted here on the forums before - ethanol cannot be put into pipelines because it likes water and will ultimately cause pipes to rust through) but I talked with my distributor and the delivery cost for a *relatively* small amount of fuel (like 500-1000 gallons) ends up making the overall cost/gallon at least as much as 100LL. Unfortunate fact of life at least here in Reno unless and until I can convince the local FBO to put in a big tank.
greg
This is true, all gasoline is locally blended with ethanol (I think it has been noted here on the forums before - ethanol cannot be put into pipelines because it likes water and will ultimately cause pipes to rust through) but I talked with my distributor and the delivery cost for a *relatively* small amount of fuel (like 500-1000 gallons) ends up making the overall cost/gallon at least as much as 100LL. Unfortunate fact of life at least here in Reno unless and until I can convince the local FBO to put in a big tank.
greg
nomocom
Well Known Member
ethanol and pipelines
I agree, ethanol might cause the pipelines to leak. However, considering the age of many of the pipelines, I'm more inclined to think they are afraid the ethanol will CLEAN the pipeline out! All that rust and sludge in those old pipelines may well be what's keeping them from leaking
The corrosion issue has largely been put to bed. ASTM 4806 specifies a pH range and allowable acidity levels. In the last decade, the spec was tightened up significantly and product integrity tracking was improved.
And an update on pipeline practices. Kinder Morgan is piping ethanol in Florida, I think for maybe a year now.
I've got a Rv-3 with a 320. I didn't build the 3, but when I have things apart, or upgrade systems, it's pretty easy to make sure the the natural rubber and cork get replaced (haven't found any cork). There are lots of elastomers that work just fine with gasoline and ethanol both.
I agree, ethanol might cause the pipelines to leak. However, considering the age of many of the pipelines, I'm more inclined to think they are afraid the ethanol will CLEAN the pipeline out! All that rust and sludge in those old pipelines may well be what's keeping them from leaking
The corrosion issue has largely been put to bed. ASTM 4806 specifies a pH range and allowable acidity levels. In the last decade, the spec was tightened up significantly and product integrity tracking was improved.
And an update on pipeline practices. Kinder Morgan is piping ethanol in Florida, I think for maybe a year now.
I've got a Rv-3 with a 320. I didn't build the 3, but when I have things apart, or upgrade systems, it's pretty easy to make sure the the natural rubber and cork get replaced (haven't found any cork). There are lots of elastomers that work just fine with gasoline and ethanol both.
Even the 100LL purists have complaints about the cork, many builders discard the cork and use something else.
mtbowhunter
Member
I have had a similar experience as Bruce, but on a smaller scale. I live in northcentral Montana and we have a refinery in town. I just called them, spoke to one of their quality control personnel, told him why I was calling and he told me the location of all the stations nearby where they ship their autogas and to which of those they ship only ethanol-free gasoline. Those are the only stations where I buy the autofuel for my Citabria or RV9. Testing of each load has verified no ethanol in the gas.
Joe.
eric_marsh
Well Known Member
I'm somewhat surprised to see that while there has been quite a bit of discussion in this thread about ethanol, there is none about lead content.
Lead has two functions - first it is a relatively inexpensive way to raise octane and second it lubricates valve faces and seats. When the government specified unleaded fuel the automotive manufactures countered by hardening the valve faces and valve seat to compensate for the lack of lubrication. This was a real problem for a lot of the big sixties engines, especially muscle car engines with higher spring pressures. Unless the heads were rebuilt with at least hardened valve faces (I don't recall if they are using stellite or perhaps just heat treating) the valves tended to hammer out. There are lead substitutes you can buy to help alleviate this problem. I know one guy who even makes his own high octane fuel by adding his own tetraethyl lead. Personally I consider this to be extremely dangerous because of lead's toxicity.
I don't know if newer aircraft engines have hardened valves and seats or not, and if they do what the story is on older ones. But it seems to me that this might be another data point to consider when thinking of using automotive fuels.
Lead has two functions - first it is a relatively inexpensive way to raise octane and second it lubricates valve faces and seats. When the government specified unleaded fuel the automotive manufactures countered by hardening the valve faces and valve seat to compensate for the lack of lubrication. This was a real problem for a lot of the big sixties engines, especially muscle car engines with higher spring pressures. Unless the heads were rebuilt with at least hardened valve faces (I don't recall if they are using stellite or perhaps just heat treating) the valves tended to hammer out. There are lead substitutes you can buy to help alleviate this problem. I know one guy who even makes his own high octane fuel by adding his own tetraethyl lead. Personally I consider this to be extremely dangerous because of lead's toxicity.
I don't know if newer aircraft engines have hardened valves and seats or not, and if they do what the story is on older ones. But it seems to me that this might be another data point to consider when thinking of using automotive fuels.
SmittysRV
Well Known Member
In the Dallas/Fort Worth area you can't find gas without alcohol in it. As far as I know, there is one small grass airport that sells mogas. We had some guys from Lycoming come to our EAA meeting, telling us the wonders of the new Thunderbolt line of engines. "They burn mogas!", they kept saying. We all looked at each other like "Do they know where they are?".
In Pedro's link extolling the virtues of using ethanol, it stated that there will be a 5% increase in performance, inclusive of all phases of flight. That sounds bogus, as I recall per volume, alcohol has less energy than gasoline. It has also been born out in folks I know driving E85 vehicles - less distance on a tank, poorer acceleration. Other experiences?
Randy Walls
Active Member
High compression
Ethanol has a higher octane rating. They bump up the compression ratio for more HP.
Ethanol has a higher octane rating. They bump up the compression ratio for more HP.
ronschreck
Well Known Member
Can the Lycoming Fuel Pump Tolerate Ethanol?
I have been useing enthanol free mogas in my RV-8 for some time now. Recently my fuel supplier started putting 5% ethanol in the premium gas. Bummer! I sent the following inquiry to Kelly Aerospace, maker of Lycoming's fuel pumps:
"I have a Lycoming IO-360 with one of your diaphram type fuel pumps installed. Please tell me what the diaphram material is made of and if it is compatable with auto fuel with 5% ethanol? This is for an experimental airplane application."
Their reply:
"Hi Ron,
This is a proprietary fuel pump we build specifically for Lycoming so I cannot release any information. Please contact Lycoming customer service for additional information."
Regards,
Timothy A. Gauntt
Kelly Aerospace Energy Systems, Inc.
Director of Warranty and Tech Support
I have just made a similar request of Lycoming. I'll let you know what, if anything, they say.
BTW, I called Don Rivera of Airflow Performance and he again confirmed that their fuel injection system is perfectly compatable with ethanol blended fuels. I asked him about the Lycoming pump and he dug out an information sheet he had in his file. Seems there are several approved materials for the diaphram in the pump, including Fairprene BM-0002 and other fabrics covered with nitrile. Fairprene BN-0002 is a nitrile coated nylon fabric. Nitrile rubber is Bunas-N, all very tolerant of ethanol. I also called Aero Accessories who make pumps sold through Aircraft Spruce and others. Their tech rep said that the pumps were not recommended for use with auto fuel with ethanol.
So, at the end of the day I'm full of conflicting information and no smarter than when I started.
I have been useing enthanol free mogas in my RV-8 for some time now. Recently my fuel supplier started putting 5% ethanol in the premium gas. Bummer! I sent the following inquiry to Kelly Aerospace, maker of Lycoming's fuel pumps:
"I have a Lycoming IO-360 with one of your diaphram type fuel pumps installed. Please tell me what the diaphram material is made of and if it is compatable with auto fuel with 5% ethanol? This is for an experimental airplane application."
Their reply:
"Hi Ron,
This is a proprietary fuel pump we build specifically for Lycoming so I cannot release any information. Please contact Lycoming customer service for additional information."
Regards,
Timothy A. Gauntt
Kelly Aerospace Energy Systems, Inc.
Director of Warranty and Tech Support
I have just made a similar request of Lycoming. I'll let you know what, if anything, they say.
BTW, I called Don Rivera of Airflow Performance and he again confirmed that their fuel injection system is perfectly compatable with ethanol blended fuels. I asked him about the Lycoming pump and he dug out an information sheet he had in his file. Seems there are several approved materials for the diaphram in the pump, including Fairprene BM-0002 and other fabrics covered with nitrile. Fairprene BN-0002 is a nitrile coated nylon fabric. Nitrile rubber is Bunas-N, all very tolerant of ethanol. I also called Aero Accessories who make pumps sold through Aircraft Spruce and others. Their tech rep said that the pumps were not recommended for use with auto fuel with ethanol.
So, at the end of the day I'm full of conflicting information and no smarter than when I started.
ronschreck
Well Known Member
Lycoming responded...
I sent a letter to Lycoming, inquiring about the material used in their fuel pump diaphragm. I didn't really expect to get an answer, but the following email was received today:
Dear Sir,
Thank you for your inquiry.
The information you requested is proprietary and is considered a trade secret.
Please contact us if we can provide further assistance.
Best regards,
Bart Kinley
Field Service Engineer
Lycoming Engines, a div. of Avco Corporation
Office Telephone: 570-327-7064
Fax: 570-327-7113
I'm going to take the diaphragm out of an old Lycoming fuel pump and immerse it in E10 mogas and see what happens. I'll post the results here. Be patient, this may take a few months.
I sent a letter to Lycoming, inquiring about the material used in their fuel pump diaphragm. I didn't really expect to get an answer, but the following email was received today:
Dear Sir,
Thank you for your inquiry.
The information you requested is proprietary and is considered a trade secret.
Please contact us if we can provide further assistance.
Best regards,
Bart Kinley
Field Service Engineer
Lycoming Engines, a div. of Avco Corporation
Office Telephone: 570-327-7064
Fax: 570-327-7113
I'm going to take the diaphragm out of an old Lycoming fuel pump and immerse it in E10 mogas and see what happens. I'll post the results here. Be patient, this may take a few months.
Pilottonny
Well Known Member
Go for the pure stuff!
Ron,
Just put it in pure Ethanol, that will make your test go 10 times faster.
Regards, Tonny.
Ron,
Just put it in pure Ethanol, that will make your test go 10 times faster.
Regards, Tonny.
Riv said "An Octane rating is representative of a fuels resistance to ignition ", but I think he meant detonation instead of ignition. In the fuel lab we had a cool variable compression one cylinder four stroke. You could raise or lower the cylinder assembly with a crank while it was running and read the scale for the current compression ratio. Tighter you can squeeze it without blowing up (diesel ignition), the more TE you get. Heptane (9 carbs) will not detonate, period. Octane with eight carbs is pretty good. Octane rating is sposed to represent % equivalent of octane. Strictly a detonation rating. As I've posted before, there are tons of kits out there to rebuild "AC style" pumps for ethanol. They run about $40. Ethanol (or methanol) raises octane rating, which is why some places have ethanol in their midgrade but not in their regular. I think we'd all better get used to the "moonshine" though. There's only a couple 100LL producers left and compared to autofuel it's something less than 1% of all gasolines. If the EPA doesn't get us I think the market will.
Greg Arehart
Well Known Member
Ron,
At least Lycoming responded, but I think it is disgusting that they are hiding behind the "proprietary" label. IMHO, that is just BS trying to keep folks like us afraid of using anything but avgas.
Sorry, had to vent on this one....
greg
At least Lycoming responded, but I think it is disgusting that they are hiding behind the "proprietary" label. IMHO, that is just BS trying to keep folks like us afraid of using anything but avgas.
Sorry, had to vent on this one....
greg
The Franklin engine uses a mechanical fuel pump that is the same as a car, IIRC a Corvair. Surely a Lycoming will accept some kind of standard pump that automotive rebuild kits are available for?
The ethanol is now blended at the refineries, here in Washington, I'm told. The local station that sold ethanol free fuel switched last month. Just after I invested in the EAA mogas STC for the C-182
The ethanol is now blended at the refineries, here in Washington, I'm told. The local station that sold ethanol free fuel switched last month. Just after I invested in the EAA mogas STC for the C-182
Unleaded Fuel
I have been running BP 93 octane unleaded fuel that is alcohol free in a 160 horse O-320 for the past several months. So far there has been no performance issues with this combination. There is one problem I do not like though. This fuel will permanently stain your paint job. On the belly of my RV-4, downstream of the fuel tank vents, are yellow streaks that cannot be removed. It's the same color of the fuel. Beware if you prize your paint job!
I have been running BP 93 octane unleaded fuel that is alcohol free in a 160 horse O-320 for the past several months. So far there has been no performance issues with this combination. There is one problem I do not like though. This fuel will permanently stain your paint job. On the belly of my RV-4, downstream of the fuel tank vents, are yellow streaks that cannot be removed. It's the same color of the fuel. Beware if you prize your paint job!
Greg Arehart
Well Known Member
Good thing my airplane is yellow!
greg
greg
frankh
Well Known Member
Just to clarify
Lycomings and clones have used hardened valves and seat for about 25 years..The lack of lead from a valve/seat perspective is a non issue unless you have a very old engine.
I believe Dave (who worked at Superior at the time) told me this.
Frank
Lycomings and clones have used hardened valves and seat for about 25 years..The lack of lead from a valve/seat perspective is a non issue unless you have a very old engine.
I believe Dave (who worked at Superior at the time) told me this.
Frank
