Aircraft fuel in antique auto's

[1929Chrysler]

I had heard one time that antique auto museums put aircraft fuel in their autos because of how long they sit without being run. Is this true? I believe I was told this is because it would prevent varnish build up in the gas and the fact that there is no ethanol in it.

Is there any truth to this and if it were that good for their cars how easily would it be to obtain aircraft fuel for our cars?

Thanks

Dan

[Guest elmo39]

Probably the main reason is that aircraft gas has lead in it , i have heard of guys here in NZ using it mixed with ordinary gas in there old cars because of this reason , what there mixing ratio is i have no idea.

[hchris]

Avgas goes off just like any other fuel, I have access to it from time to time and find its better to use it straight away rather than store it. From memory earlier this year I had a 20 litre drum stored for 2-3 months came to use it and the car just wouldnt run.

As to harmful effects, well yes it still contains a percentage of lead which we are told is bad for the environment, as to engine performance its great - 100 octane makes the old girl get up and go !!

CJH

[Bhigdog]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> how easily would it be to obtain aircraft fuel for our cars?

</div></div>

As easy as going down to your local small airport ( stay away from larger control tower type fields ) with a gas can and $6.00+ per gallon........Bob

[hchris]

Bhigdog - thats interesting, down here its actually illegal for aviation fuel outlets to sell to motorists, I think its because of the lead issues; however there is provision for a permit to be granted to a motorist who can justify the need to use it such as race car operators etc.

CJH

[Guest elmo39]

hchris

Im find it interesting that your fuel went off after 2-3 months , at the moment it is duck hunting season here in NZ , at the start of the season (about 4 weeks ago)i got out my 6hp Johnson out board which i use to cross the lake i hunt on . It hadn't been used for over 12 months as i never went hunting last year . There was still a couple of gallons of over 12month old fuel still in the tank ,it started first pull on the starter cord and is still running sweet after 4 weeks of use almost every day, and there is no sign of varnish build up ,and the fuel still smells fresh

[Dave@Moon]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: hchris</div><div class="ubbcode-body">Bhigdog - thats interesting, down here its actually illegal for aviation fuel outlets to sell to motorists, I think its because of the lead issues; however there is provision for a permit to be granted to a motorist who can justify the need to use it such as race car operators etc.

CJH </div></div>

It's illegal in part because of the lead, but mainly because there are no road taxes appplied to av-gas.

[Tom M]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Bhigdog</div><div class="ubbcode-body">As easy as going down to your local small airport ( stay away from larger control tower type fields ) with a gas can and $6.00+ per gallon........Bob </div></div>

That is what my friend does. We have a few subdivions in the area that have their own little airport/runways that where he get his AV gas.

[Ron Green]

I used aviation fuel for years in my GTO, not because of the fuels shelf life but because of the octane. There is a airport close by. I found it odd walking through a airport lobby with two 6 gallon gas cans. Not only was it expensive it was a pain in the a$$ since the GTO was a fuel hog. I switched to racing fuel since we have a dirt track close by.

If you want a excellent fuel stabilizer I have used this product for many years and it last for 3 years.

http://www.hirschauto.com/prodinfo.asp?number=FPS%2D01

[Airy Cat]

I have used 100 LL Avation gas in my '65 Wildcat and my '65 Corvette for over 15 years and have never had a problem with it. In the Buick I mix it 50/50 with premium unleaded in the Corvette (327ci/365hp) I run it 100%. The main reason that it is illegal to use in an automobile is that there is no road tax when you buy av gas. So, the govt. gets upset.

[Ron Green]

I never had a problem with it either however if Dan is only looking to extend the shelf life as he states it would be a lot easier and cheaper to use a stabilizer.

[carbking]

As mentioned by several, legal issues arise from:

(A) some (but very little anymore) lead

( no road taxes

As mentioned by others, 100 octane would run fairly well in a high compression vehicle (10 or more to 1 compression) such as a GTO without modifications.

For older lower compression engines such as those produced before the horsepower race began circa 1955, the engines will RUN BETTER ON LOWER OCTANE FUEL!

Contrary to popular opinion, given three gasolines (no deathanol mixed in) of 100 octane, 80 octane or 60 octane; each has an energy content of 117,600 BTU/gallon. There is no difference in the energy content. This will become lower with the mixing of deathanol with gasoline.

Octane is simply a measure of the speed the fuel burns, not of energy content. Higher octane is slower burning! Lower compression engines will NOT run so well on the higher octane fuel without carburetion and timing changes; and will still not run as well on the higher octane as on an octane more in line for the compression ratio of the engine.

And, according to friends who are pilots, the avgas of today has no greater shelf life than automotive fuel. I cannot verify this personally, as I do not use the stuff.

Waste of money for low compression engines (my opinion, others may differ).

Jon.

[nearchoclatetown]

Hey Carbking, try explaining the slower burning higher octane gas theory to the people that buy hi-test in winter so their car starts easier!! I've tried for years, they don't believe it.

[R W Burgess]

Wait! Now, I'm confused. I always thought high octane gasoline would not crud up as badly in the winter time. I've been using it in my high compression engines during the winter for years just because of that.

Was I wrong in thinking my injected Corvette was not being helped with this tactic??

Wayne

[Matt Harwood]

Carbking is exactly right. If your engine doesn't knock or ping on regular, it doesn't need premium. All it measures is the fuel's resistance to detonation. It doesn't add power or burn cleaner or clean the gunk out. It just doesn't light-off as easily. Your 200 HP engine is only going to make 200 HP no matter what kind of fuel you put in it.

Wayne, if you've got high compression, you might need it. Below about 9.5:1, though, I bet it runs fine on regular. While I don't know exactly why, my Mustang with a 342 inch stroker and about 9.8:1 compression runs fine on mid-grade, and gets notably worse gas mileage (like 20% less) on high octane.

Here's an article I wrote on the subject:

Automotive Myths

[carbking]

Matt - the answer to why your Mustang gets less mileage on high octane may be deathanol.

Here is Missouri, before our wonderful governor decreed that ALL fuel pumps in Missouri would have at least 10 percent deathanol in the fuel, some of the companies added deathanol in higher octanes, as it was/is higher octane than gasoline. Since the energy content is much lower, less mileage.

Since deathanol has become the standard in Missouri, my vehicles are down from 10~15 percent across the board on mileage. The newer computerized fi units seem to handle it better simply because the knock sensor will allow the computer to dial in as much advance as the engine can use, thus helping to burn all the fuel. To do the same thing with a carbureted engine requires resetting the timing. Doing this on my carbureted vehicles did help.

Jon.

[Dave@Moon]

Virtually all the gas sold in Iowa since 1979 has been E10. (In the early 1980s Conoco was the last holdout with "pure" gasoline. I don't know how long that lasted.) It should not effect mileage more than about 3-5%. If ethanol was inert it would only reduce the energy load delivered to the cylinders by 10%, and mileage accordingly.

I ran a 1960 Falcon for 3 years (30,000 miles) on Iowa E10. It didn't matter. If it mattered that much nobody in Iowa would've been able to run an old car for decades now.

[carbking]

Dave - whatever year the POCI and GTOAA conventions were in Redwing, MN, we came back through Iowa driving a factory turbocharged 1979 Mustang. I had forgotten about the deathanol in Iowa, and neglected to fill up before getting to Iowa. Filled up with premium (the turbo will cause detonation on lower octanes in the Mustang, somewhat modified). Car would not run the speed limit, spit, sputtered, backfired, just very unhappy. Engine heated when we tried to run the AC. We limped through Iowa and filled up in Missouri. Took about 5 miles before the garbage in the fuel lines and the garbage in the carburetor were gone, and then it was like turning on a switch.

Now that Missouri also has E-10, I have recalibrated the carburetor, and the car is happy, but fuel economy went from about 25 to about 21. And yes, I keep records, and have calibrated the odometer.

And in my business, I have to contend with deathanol daily. Yes, it can be made to work; just not as well or as inexpensively as gasoline! (my opinion, others may differ).

Jon.

[Guest wk's_olds]

I use the product Sta-Bil (stabilizer) 2 0z to 5 gallons of fuel. I also add the lead additive because my '51 Olds rocket engine requires leaded fuel.

[35gene]

I am with Wk's olds i do the some with my 35 chevy and my 54 ford.

[Rusty_OToole]

What Carbking said, the best experts have been saying for years.

Your engine will run best, make the most power, best mileage, and run cooler, start easier on the kind of gas it was made to run on.

My rule is the octane should look like the compression ratio. 8.7 compression = 87 octane gas, 9.2 compression = 92 octane. Naturally you have to use some leeway here, it is not an exact rule.

But an old, old car with 5:1 compression will run best on a fuel that resembles lamp oil.

Some owners mix kerosene with their gas to reduce the octane.

I put this statement on this board once and it got debated pro and con. Then one person chimed in that he ran a 1932 Buick for thousands of miles on 25% kerosene and 75% regular gas, towing a trailer and going to all kinds of old car events and tours.

The first time I heard of this trick was in a story about English vintage motorcycle enthusiasts who mix kerosene with their gas, or paraffin with their petrol as they say over ome.

[Guest Bob Call]

Carbking is correct, all gasoline, without ethanol, has the same BTU content. The reason for higher octanes is to prevent detonation or "knock' by the alteration of the burn rate. If you engine knocks on 87 octane step up to 89, still knocks, step up to 91 or 93 (whichever is marketed in your area). Still knocks, use an octane booster additive. Of course ignition timing should also be taken into consideration if you are having knocking.

Buying a higher octane gas than what your engine needs to run without knocking is a waste of money.

[mrpushbutton]

As far as museums are concerned, I'll chime in, having worked in car museums for the last 16 years. The best thing to do for a museum car is to disconnect the fuel line and let the bowl run dry just as you take the car into the building for long-term display. we rarely had the time of day to do that at either museum I have worked at, we just had time enough to get the car in place and get to the next hot task. Some of those cars would start up later just fine, others--not so much, about 50-50 in numbers. There was a period where cars that we took out and campaigned in 1992-'93 would all have this funky green jelly in the bottom of the bowl that the float was glued to--the lighter elements evaporate out of the fuelfirst, then the next heaviest, then the next, etc. until you are left with what you are left with. I have looked in old carbs from cars that have not run in years and there might be some darker brown residue left behind along the edges of the bowl but not the goo that we encountered later. You get really good at doing carb and fuel pump rebuilds, that is the one way to make the car run right after pulling it from display and waking it up. Most non-gearheads in the museum administration field (most of them) don't like the smell of old car exhaust lingering in the museum, especially when banquets and meetings are a big income producer.

In an ideal world you could run the cars on a regular schedule to keep everything alive, keep seals wet, etc. but it is the exception rather than the rule.

Brakes are another long-term "sitmobile" problem. Disc brakes and museums don't mix very well. Silicone Dot-5 fluid is our friend for drum brakes, absolutely no ill effect from sitting.

[Ron Green]

As I posted above Bill Hirsch’s product will keep the gas from going bad and easily last 3 years plus.