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E10 fuel and Lycoming fuel pump

D

David-aviator

Well Known Member
I'd like to burn 91 octane mogas but can not buy it without ethanol in this area.

The unknown element in the fuel system with regard to E10 is the mechanical fuel pump. I know there have been and are aerobatic guys flying with pure ethanol but I have been unable to find out where their fuel pumps came from. I even called an engine shop in California that built at least one such engine and they would not comment on the fuel pump and ethanol.

Lycoming fuel pumps could easily be built with materials resistant to E10 fuel. Don Rivera has been building his fuel injection systems with such material for some time - why not the darn fuel pump?

Is anyone here running E10 through the standard mechanical pump at this time? I have a feeling the pump may in fact be built with such materials but manufacturers won't comment out of the old liability issues. A while back Tempest was actually testing the materials aiming for certification but one of their guys told me the program was terminated without comment. He said he could not comment on the subject. Sounds like a lawyer got involved.

For sure some company has built a pump with suitable materials, there are airplanes flying on E100 powered Lycoming engines.
 
I fly mogas with 10% ethanol with mechanical fuel pump on an O-360-A4M. The aircraft is 6.5 years old and 1100 plus hours. Dan
 
Mechanical fuel pump and E10

I was also looking for a fuel pump rebuild kit that would tolerate E10, but was told you can not buy fuel pump rebuild kits at all.

I was "told" that all new and rebuilt pumps now use "E10 Tolerant" rubber parts, but when I ask what that meant: Silence.

I have not heard the in-flight re-start issue before. I wonder what is happening that might cause that?

Dkb
 
Been flying 91 E10 for the last couple of years.
I keep track of all the mogas that I burn and so far I've just topped 1000 Gallons.
I keep avgas in one tank mostly so I can have the airplane sit around with avgas in the system but 91 octane E10 is no problem as far as I can tell.
I have a sophisticated engine monitor with data logging and I keep a close eye on trends and anything abnormal.
I know one thing, it runs smoother and leaner on mogas than avgas and keeps the engine and plugs clean.
The mechanical pump does not show any sign of letting up and from what I know the materials that cannot tolerate ethanol are not even available anymore. No one will certify that claim and dealing with today's litigious society who can blame them.
Lots of people are using 91 octane E10 but most got tired of preaching and answering trumped up fears and old wife's tales.

Aero Sport IO 540 8:1 CR
AFP fuel injection
One Lightspeed ignition and one maneto
Constant flow fuel return line (no vapor lock issues)
 
N427EF said:
I keep avgas in one tank mostly so I can have the airplane sit around with avgas in the system but 91 octane E10 is no problem as far as I can tell.
I have a sophisticated engine monitor with data logging and I keep a close eye on trends and anything abnormal.
I know one thing, it runs smoother and leaner on mogas than avgas and keeps the engine and plugs clean.
The mechanical pump does not show any sign of letting up and from what I know the materials that cannot tolerate ethanol are not even available anymore. No one will certify that claim and dealing with today's litigious society who can blame them.
Lots of people are using 91 octane E10 but most got tired of preaching and answering trumped up fears and old wife's tales.

QUOTE]

My thoughts exactly.

Bevan
Click to expand...
 
It works....but just as Ernst has done, you will need to do exactly what he has done.

The issue is 91 E10 will work but there is no room variables. It certainly will not pass certification tests as is required by the FAA for the new unleaded fuels projects. I have first hand seen this on the engine test stand many times.

The future for an unleaded 100MON aviation gasoline is looking bright, and when it is available at the airfield, all our engines will run healthier and longer, much longer. Look what happened to car maintenance on ULP.

Hang in there a little bit longer. ;)

The other issue is gum deposits from olefin content. And mogas is full of all sorts of things, and I have become very skilled at removing cleaning and reinstalling the carby's on my near new Yamaha 175HP V6 outboard. :mad: Why? Mogas and gum deposits from infrequent use.
 
I do this

I run a mixture of ethanol free 87 octane mogas and 100LL in my right tank only. I did run some E10 in my mixture this summer with no ill effects that I could see but I do as Ernst does and leave nothing but a gas in my fuel lines and carb and pump when parked. I personally think that when the ethanol sits in the lines is when your likely to have a problem but that is just my theory. I choose not to buy E10 for my mixture the other day with winter approaching increasing the chance for the ethanol to absorb water. I use a 105 gal slip tank, right now I put in 60 mogas, 45 gal 100LL. That fuel for me is 4.45 a gallon. I figure if I save a buck or more a gallon over Avgas it's worth it. Avgas is 5.55.

Randy
8A
 
your own flying science experiment, with little knowledge of what is actually going on.......:cool:

I would avoid the 87 altogether no matter what you think already. What goes into it is seriously random. Two of my best friends are the engineering stuff for two of the major refineries......even they will not use anything less than the premium unleaded in their cars and one in their subuaru powered RV8.....that tells you something.

The less you know the better it sounds.
 
Vanguard Squadron

The Vanguard Squadron, 16 plus years of ethanol use
Gary Kuhns, lead pilot of the air show squadron, ?The Vanguards? has info on ethanol use. This is no surprise, they have been practicing and performing in RV-3s all the while running the IO-320 engines on ethanol and all mixtures of ethanol and avgas when flying x-country to and from the show sites. I figure with their 16+ years of ethanol experience, they can provide some insight for my own flex fuel project. In addition, by putting the team?s experiences out here on the board, hopefully it will answer a question that has come up occasionally on the vansairforce boards. What about the Vanguard Squadron? What have they done to the airplanes so they are ethanol compatible?

This posting is based on 3 or 4 conversations I had with Gary during 2010. The last conversation we had, Gary added some clarifications and corrections to the draft I had sent him.

Basics on the Vanguard airplanes
Four similar Rv-3 airplanes, N6GT, N16MR, N19EH, N25RV
IO-320 and wood Sensenich propellors

Fuel system
Like many other early Rv-3s, all four Vanguard airplanes have 24 gallon fuselage tanks. However, two of the four also sport wing tanks giving them impressive fuel capacity. None of the fuel tanks were built using special procedures or unusual materials as the planes were built with avgas in mind. Aerobatics are flown with wing tanks (if present) empty and fuel feeding from a flop tube inside the fuselage tanks. All have a factory type mechanical fuel pump and backup electric pump on the firewall. In order to accommodate the higher fuel flow needed with ethanol, Airflow Performance, Inc has re-calibrated the Bendix fuel injection systems. None of the airplanes have fuel drain sumps or gascolaters, Gary reports they were removed when they realized they weren?t performing any function. There is no separation of water and any particulates are trapped at the screened inlet to the Bendix fuel servo. All four have avgas priming systems for cold starts. They use a small fuel tank, (weed-wacker size) mounted behind the seat to feed the priming system.
Click to expand...
Can't argue with real life experience. Keep in mind their engine parameters are a little different in that they have used pure ethanol or any mixture of avgas and mogas, whatever was available according to their first hand account.
Can't argue with engineering data either:
The fellow who really convinced me that nothing will go wrong with mogas flies on a West Coast formation team and had at the time accumulated over a thousand hours using nothing but the cheapest 87 octane E10 mogas.
He had done no modification to his mechanical/boost pump and carbed set up. He did report a couple of vapor lock hick ups and that is something I addressed with my fuel system. His airplane as well as the Vanguard airplanes all sit around soaked in ethanol gas and their mechanical pumps are showing no signs of deterioration.
I do believe letting airplanes ,cars or other gasoline engines sit around unused for long periods of time is cause for concern.
 
RV10inOz said:
your own flying science experiment, with little knowledge of what is actually going on.......:cool:

I would avoid the 87 altogether no matter what you think already. What goes into it is seriously random. Two of my best friends are the engineering stuff for two of the major refineries......even they will not use anything less than the premium unleaded in their cars and one in their subuaru powered RV8.....that tells you something.

The less you know the better it sounds.
Click to expand...

So which is better, 91 octane ethanol blended fuel or my non ethanol mix, roughly 60% 87 40% 100LL?
 
Thanks for the replies reflecting personal experience with E10 fuel. That's exactly what I was looking for.

I do not fear mogas. But I am practical enough to know it has its limitations as do all matters in this business.

What I learned over several years operating the Subby H4 and H6 engines with mostly E10 fuel was that its vapor pressure had to be checked with every load of fuel, it was not constant. 100LL is very constant in this regard, but not so with mogas, I've checked both. System compatibility was not an issue.

The mechanical fuel pump with the Lycoming engine has been the sticking point (with me) in evaluating mogas use. I can manage vapor pressure and vapor lock issues but not a failed pump due to incompatible materials.

But that issue seems to be resolved with the reports here. I have had a strong suspicion that compatible materials were being used to build the pumps but could not get anyone to admit it. One conversation with a tech guy at Tempest revealed that while he would not confirm what materials were being used, he did say pilots were running ethanol through them and there have been no reports of failure.

Thanks again for the response. I appreciate it.
 
N208ET

I can't answer that question. The answer is a an aviation grade 100MON fuel. At the moment the one available is 100LL, not too far down the road the far better for our engines answer will be an unleaded 100MON. But it is not for sale just yet.

The next issue is a safety of flight problem. Davia -aviator above posted
The mechanical fuel pump with the Lycoming engine has been the sticking point (with me) in evaluating mogas use. I can manage vapor pressure and vapor lock issues but not a failed pump due to incompatible materials.
Click to expand...

So think about this, if you had flown 2.5 hours and stopped for a restroom break and took off on a warm day, and your boost pump circuit breaker popped not long after entering cloud but below the LSALT and you were running mogas with lord knows what RVP.......:eek:

I had this happen recently, and had vapour locking affecting fuel pressure when using reduced fuel flows, I had to run full rich for a long while to cool th system off enough to run LOP.

Had that been mogas, I would most likely had an engine not able to operate. :eek: This was an AFP pump.

I will say this again, Ernst (N427EF) has a system and a procedure that works for him.....BUT, he still uses 100LL and for good reason.

The next thing I want to raise is the 1999 Mobil (Exxon) Avgas contamination event. This was a massive problem, and deadly serious. In the Avgas world this was traceable and safety was ensured, but many aircraft required repairs at great cost. Fortunately nobody was hurt.

Had this been a load of mogas ........nobody would have said anything and who would care. Read these links and the ATSB report very carefully.

http://www.atsb.gov.au/publications/2009/avgas-fuel-contamination-event-1999.aspx

http://avstop.com/news/avgas.html

Will the fuel burn...yeah...but.....Is it really worth the hassle when in a short period of time an effective safe and aviation grade of unleaded avgas is coming?
 
Our local fuel distributor said

All of their gas arrives as 87 octane regular gas. Ethanol is an octane booster so the higher the grade of fuel you buy from them the more ethanol your getting per gallon. Don't know if it's true or not. As I understand it, if the ethonal absorbs water the octane rating goes down. It's my opinion that E10 can be run successfully through my motor the way I operate it. I'm not however going to let it sit in a metal tank over the winter months however subject to many iterations of heating and cooling-(condensation)

RV10inOZ

Could you ask your friends my question.
 
I can not help but make the casual observation that those who are most critical of mogas are those who have not tried it.

AVGAS is good, no question about it. The GA world floats in it. But as one of the guys at a OSH seminar commented on 100LL, it has over 80 blending ingredients. That's one reason the stuff is expensive and it has a track record of problems, like causing carburetor composit floats to sink. I had that problem with a C-150 once upon a time. And 100LL has had its challenges with vapor lock, that's why some certified aircraft recommend use the electric pump during climb.

As mentioned earlier, just about every aspect of what we do here has its limitations. Mogas is a viable alternative to 100LL if one recognizes its limitations. There may come a day when that is our only alternative if the EPA has its way with lead emissions in this country.
 
RV10inOZ

Could you ask your friends my question.
Click to expand...

Which friends? ;)

I know who you mean but the question is akin to "what cake mix should I use for the best result?" The question is far to open ended and publicly providing an answer which may then be used in the wrong context is unwise.

I am happy to discuss this with you privately on skype one day, and yes I have seen far more of this stuff on the Engine test stand than many, but anything more than that, is not going to happen. If you want to talk to me directly, PM me your details. Happy to help.
 
David,

You mention that you check the vapor pressure of your samples. What do you use to do that? And, how does it compare to 100LL in your testing experience in actual data, how ever it is measured.

BTW- I just found some data that showed you will need 1 psi higher pressure to the inlet of the mech pump to equal non E10 mogas.

You apparently know and mitigate the risks of mogas and E10. I think people are not as negative as much as not willing to recommend this path to others without defining the risks along with their mitigation factors. Honestly, it is not for me, at least not yet. I have have to finish my first build now. But I am still interested in the successful configurations.
 
BillL said:
David,

You mention that you check the vapor pressure of your samples. What do you use to do that? And, how does it compare to 100LL in your testing experience in actual data, how ever it is measured.

You apparently know and mitigate the risks of mogas and E10. I think people are not as negative as much as not willing to recommend this path to others without defining the risks along with their mitigation factors. Honestly, it is not for me, at least not yet. I have have to finish my first build now. But I am still interested in the successful configurations.
Click to expand...

First off Bill, I do not recommend the use of mogas or E10 fuel. I only seek information on the subject to satisfy my personal curiosity.

I have a vapor pressure test kit that came from Petersen Aviation, the provider of mogas STC's for certified aircraft. (They strongly strongly discourage the use of fuel with ethanol)

The test kit is very simple, a tube, a plunger and a gage. It is designed for use with an STC to determine if fuel vapor pressure is safe for flight. The gage reads pressure in kPa's. When a test is done, the reading should be above a red line, which I believe it is 34. Most mogas tests in the mid 40's. 100LL always comes in at about 62kPa's. (as I commented earlier, it is good stuff)

This subject has been contentious. That's why guys using mogas quietly go about their business without much comment unless asked, they are having success and could care less what anyone thinks about it.

I got some good information on the Lycoming fuel pump and that's all I was after.
 
David-aviator said:
<snip>
The test kit is very simple, a tube, a plunger and a gage. It is designed for use with an STC to determine if fuel vapor pressure is safe for flight. The gage reads pressure in kPa's. When a test is done, the reading should be above a red line, which I believe it is 34. Most mogas tests in the mid 40's. 100LL always comes in at about 62kPa's. (as I commented earlier, it is good stuff)
<snip>
Click to expand...

Thanks David - This is some good, real data. I am casually proceeding on sorting out what kind of test could (easily) be run on the fuel system during either build and/or phase I to validate and quantify the fuel system ability for maintaining fuel flow. That would entail getting temperature and pressure at the inlet of the mechanical pump. The thought is to quantify the systems limits and margin, in terms of fuel temperature, fuel flow and a limited fuel characteristic, like RVP. You get the idea.

The overall idea being, I would not fly without knowing usable fuel, and why would I fly without knowing the limits of my fuel system?

Thanks for the data. (" Just the facts, Mam" : Joe Friday, always liked that guy)
 
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I would not fly without knowing usable fuel,
Click to expand...

Glad to hear that! So make sure you run a tank dry in flight and refill to confirm exactly what is usable. Don't do it on a short final though ;)

I see you are using an IO engine. Ask why the Petersen STC's are not done for the IO's and think RVP. ;)
 
BillL said:
Thanks David - This is some good, real data. I am casually proceeding on sorting out what kind of test could (easily) be run on the fuel system during either build and/or phase I to validate and quantify the fuel system ability for maintaining fuel flow. That would entail getting temperature and pressure at the inlet of the mechanical pump. The thought is to quantify the systems limits and margin, in terms of fuel temperature, fuel flow and a limited fuel characteristic, like RVP. You get the idea.

The overall idea being, I would not fly without knowing usable fuel, and why would I fly without knowing the limits of my fuel system?

Thanks for the data. (" Just the facts, Mam" : Joe Friday, always liked that guy)
Click to expand...

Here is a method from a previous thread for testing vapor pressure:

http://www.vansairforce.com/community/showpost.php?p=766364&postcount=43

20130428_090853.jpg
 
This subject has been contentious. That's why guys using mogas quietly go about their business without much comment unless asked, they are having success and could care less what anyone thinks about it.
Click to expand...

You have no idea how many people use mogas E10, its all there is around here.
Some even in certified airplanes.

We all accept the fact that 100 Octane is a better fuel.
Fuel systems should be designed to tolerate 87 octane. If your engine ever
hick upped from vapor lock low fuel pressure or other heat related issues you need to take a serious look at your installation.
The solution is very simple, It's called a fuel return line, costs almost nothing and is very simple to install if you think about it early enough in the build.
I didn't come up with the idea just copied what has worked flawlesly for others and now for myself.
For those concerned about vapor pressure, when a constant trickle of "cool" fuel in my case 6 GPH, keeps running through the fuel system, gasoline never has a chance to heat up, as simple as that. Keep as many of the fuel system components behind the firewall as you can to minimize exposing fuel system components to heat.
I have never tested the fuel I put in my tanks and nor do I want to be concerned about it. I did however thoroughly test the engine on very hot days
purposely heating up the engine compartment and taxiing around and performing take offs and landings to test for any sign of fuel pressure drop and stumbling engine performance. None found!

David, glad you got the info on the fuel pump, I flew my RV 8 with the same fuel system for 450 hours and never had the courage to put mogas in it only because I worried about the rubber parts in the fuel pump.
I no longer worry about it but like you, I consider that pump the
"hair in the soup"
 
Price of fuel is a motivating factor.....

....in this matter.

Yesterday good friend Roger Mell delivered 19.5 gallons of 100LL to my hangar. (first engine run is approaching)

The fuel was purchased at Spirit Airport in St. Louis. The invoice for it is $131.32, $6.73/gal.

Granted, mogas is temporarily down in price right now, 87oct E10 is $2.83 and 91oct E10 is about $3.20.

The same purchase of 91 mogas would have been $62.40.

What is frustrating about ethanol in Missouri is where you live. All fuel in the St. Louis metropolitan area has "up to 10%" ethanol. When we visit family in Springfield MO, Signature gas stations advertise and sell 91 octane fuel without ethanol.

I am tempted to acquire an old fuel truck and drive it to Springfield when we go to visit and load up with 91 mogas. :)

PS Incidentally, the Superior EXP OI360 engine I bought from Barrett in Tulsa is designed and approved for 91 UL Mogas and 100LL and 91/98 Avgas. Another motivating factor in this matter.
 
Status of this company?

I searched the thread for any discussion on these guys. Sorry if this has been hashed-out.
I'm just wondering if anyone has used this product... Website really doesn't say if it's being sold yet...
http://www.airworthyautogas.com/
 
We Don't Know

I've asked Lyc and Tempest several times over the years about ethanol effects on their pumps. Lyc clams up and ducks the question; they're working on a mogas spec. Tempest, albeit years ago, wouldn't commit (as now). Where ethanol is much more concentrated in the fuel stocks, e.g., Brazil, mogas operators change out their pumps every few hundred hours. Keep in mind that ethanol deteriorates materials, it's effects are not immediately catastrophic. For those who claim years of E10 exposure, you really don't know the long-term affects of E10 on your fuel system.

Regarding the thread steal about using mogas, I've run thousands of gallons through a half-dozen aircraft over 20 years. I recognize it's limitations. You pays your money and takes your choice.

But ethanol is a different story. Tariffs, mandates, and subsidies keep it alive. I disdain and avoid ethanol; it's a politically driven crappy fuel, particularly for aviation. Experimenting, one tank with 100LL and the other with E10, an RV-7 slowed down 4 mph during 75% cruise when burning E10.
As a side note, it took over two minutes after switching tanks for the alternate fuel to reach the engine. Keep that in mind if you ever encounter fuel starvation off one tank. You'll descend a couple thousand feet before fresh fuel gets to the engine after switching tanks.

John Siebold
 
David-aviator said:
....

I am tempted to acquire an old fuel truck and drive it to Springfield when we go to visit and load up with 91 mogas. :)
Click to expand...

David, Don't they deliver in trucks already? Meaning: if you really want it you can get it from the local distributor. Just get a "farm tank" , with EPA approved catch basin and you are in business. Ethanol blending takes place at the distribution terminal, upstream toward the refinery. (http://www.eia.gov/oiaf/servicerpt/fuel/srfsappc.html )The "lubricating" additive is also added there with the ethanol. It is NOT soluble in alcohol and looks like clear Karo syrup. You don't want this stuff.

Personally, knowing that the stability of that fuel is lousy and it smells bad and degrades in a few months, I don't think a large supply would be good unless the distributor recommends some stability additive.
 
RV7ator said:
Experimenting, one tank with 100LL and the other with E10, an RV-7 slowed down 4 mph during 75% cruise when burning E10.
Click to expand...

Trade 4mph in cruise for half-price fuel? I'll take that every single time.

RV7ator said:
As a side note, it took over two minutes after switching tanks for the alternate fuel to reach the engine. Keep that in mind if you ever encounter fuel starvation off one tank. You'll descend a couple thousand feet before fresh fuel gets to the engine after switching tanks.
Click to expand...

Not necessarily true - it took two minutes to burn the fuel out of the lines, but if the lines were truly empty, and they would be if the tank ran empty and then lost fuel pressure, then the fuel pump is pushing against an empty line instead of a line full of pressurized fuel and it will catch up within seconds. People do that every day.
 
Airguy...

4 mph is the ethanol effect. I use more mogas than 100LL and neither has a speed advantage. Thank goodness that where I live there are several sources of pure gas.

I wrote "starvation" not "exhaustion", thinking your very point. Also consider contamination, like misfueling and you want to abandon the tank source. 2 minutes.

John Siebold
 
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