AV gas, can you use it in older tractors

I was just wondering if anyone has tried using aviation gas (not jet fuel) in older tractors. We use it in our tow tractors and it seems to run good with no side effects so I was just curious.

That could get expensive. I think I'll stick with 87 octane

On a low compression engine I don"t think you will gain much.

(quoted from post at 08:16:59 02/28/10) On a low compression engine I don"t think you will gain much.

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If you have big plans to gain hp using it Jeff Z is correct. They have done studies and you actually lose power when you run too high of octane fuel. The study showed you should run the lowest octane fuel possible w/o the engine pinging.

With that said, it is really clean fuel and a better grade. For the super low hours we put on these tractors you don't burn enough gas to keep it fresh. Maybe if you put better fuel in you won't get the ill side effects of dirty, old fuel.

I'm not actually not thinking of using it to gain hp or anything. I can get it for free at work so I just thought if it won't do damage it might be a cost saver. It would be going in a 706 and keeping it full is killing me this winter.

Isn't that 706 gasser a 10.5:1 CR?

Gordo

Myself i believe that is a little over kill as 93 does vary well in a 706 gasser . As to the amount of gas that goes thru one in a day i never thought that it was that bad. I have run 706 gassers since about 1980 and when they are tuned correctly they do a vary good job . One must stay up on keeping them tuned and just throwing a set of plugs and points in one is not a tune up . checking the timing and setting it dead on adjusting the valves once a year if you are putting hours on it working , The valve adjustment at times can be a real pain as rocker arm wear can give you a false set due to as i call it bridging from wear on the end of the rocker arm as the rockers do not always hit the valve stem dead on and most are off to the side . setting of the valve lash is a art and it really does take years to learn and setting of the valves does affect the engine's performance . The feel of the feeler gauge is not the same between two people as my set and your will not be the same . How important is valve set ???? well i can tell you this that on my 95 dodge Cummins it can mean a 3 mile to gallon difference in fuel mileage. and on a 35 gallon tank that is and extra 105 miles , and yes a 5.9 cummins needs it's valves adjusted every so often like any other solid or roller cam followers do .

The IH engine manual I have for the C221-C301 says the C221 is 7.2, C263 is 7.2 and the C301 is 7.7. Data book says the 706 came with a C263 and a C291, my manual does not mention the 291. Since the 301 is sleeveless, I wonder if the 291 is a sleeved version? I doubt if there was a tractor engine with 10.5 CR, but I'm not the one to ask, just providing the info I have.

One really positive benefit is no ethanol is added to it. Ethanol while a benefit to using less foreign oil does not keep well over time since it is a giant moisture sponge. If left long enough it won't even smell like gas let alone burn. Todays sealed fuel systems keep moisture at bay but vented fuel systems suck moisture. AVgas will store for longer periods and still burn. Stabil works well too.

One more little piece of nostalgia is the fact regular leaded gas of the sixties era was 95 octane or so.

In the '70's I was supplied av gas for my Chev 350 low compression which saved a lot driving to work.
One winter stormy night the car quit on the river bridge.
A cop came along, gave me a ride home and had the car towed.
Next day I pulled the plugs and they looked like they had been filled with solder around the electrodes.
From listening to hanger talk from experienced A&P(AI)'s AV 100LL has about twice the lead as car or farm gas.
We used av gas in the B&S engine on our tow buggy but I quit using it in the car.
Dell

Not many muscle cars of that era were 10.5 doubt if farm tractor would be near that high. If you will look at gas pump most have little sticker that says Octane= R+M/2 (or something simalar). There are 2 common procedures for determining octane research and motor, one gives a higher number than the other and the high one was posted back in seventys. Now by law they post average of the 2 methods. By todays method the old 92 octane would be around 87.

I have been concerned since a post some time ago on here suggested that leaded gas be used to help preserve the engine if working it hard. Upon inquiry, a friend suggested I mix 1/6th avaiation gas and 5/6ths unleaded in my 300u, and that would give me the necessary lead. I just started doing this so I have no experience to report.

It works very well. It is a little on the dry side. I would recomend mixing a quart of diesel with 5 gallons of av gas when the tractor is stored for the winter. Staight av gas will stick the valves over winter!

For the post you read about needing lead there are probably 100 more in the archives that say don't worry about it. Unleaded gas is fine.

Leaded gasoline low lead gasoline, and no lead gasoline are available as "av gas".
LL100 (most common leaded is not Sunoco 260!!!
it is a low lead fuel.
High lead High octane Av Gas 115/145 (rating system Numbers) is not found except at air races.
Will it work? yes. Will it be very usable, yes. Will it improve anything. No (except your wallet if it is free (be careful of free))
there are no dry or oily fuels unless they have had oil added. They do not stick valves or anything else. Moisture and sugar (including Glycol) stick engines (among many things).
The only grief associated with Av Gas is plug fowling. Plugs today can last 100K miles (or equal in tractor hours) without issues due to no lead. Look up these facts, JimN

115/145 (purple) is like Jan... said, mostly for high performance engines, 100/130 (green) is the norm these days and I imagine what you have available. 80/87 (red), from what I have heard is a thing of the past, but common back when I worked line service "back in the olden days" ('66 thru '69 when private aviation was a lot busier than today). I was told back then that avgas is very high in lead content, so the post about 1/6 avgas to 5/6 unleaded, seems to make some sense. However, due to the different methods of obtaining octane, mixing does not always come out equal to the ratio of the fuels mixed... you can even mix one type of 87 with another type of 87 and end up with 88 or 89.
I sometimes mixed fuel we drained from the sumps on the fuel trucks with my car gas, but not enough to tell any difference. We did on occasion sell 100/130 to gas drag racers as they claimed it helped.

ok for parade or shows.I would not try to farm with it.you might use it in a machine that sits for long periods of time

We did on occasion sell 100/130 to gas drag racers as they claimed it helped.

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The higher octane allows them to run higher compression and advance the timing. THAT is where they get more power.

This is something that comes back to memory from the time when I was actively flying. You might be able to check this out elsewhere. I THINK that at least one of the differences between AV gas and auto gas is in volatility, which has to do with the point at which the liquid will become a vapor. Vapor lock in airplanes can be deadly--fuel pumps don't work on vapors.
There is a good article on Wikipedia called "AVgas," which appears to have been written by a knowledgeable person, perhaps a chemist or an engineer. There, you can find historical info on avgas, as well as information on the different types available now and in the past. AThere is some discussion of using auto gas in airplanes.