Aviation gas

Used 115/130 for years in stock car{BB chev's} & my Corvair- never burned anything- when the 115/130 green disappeared & was replaced by 100 low lead some people lost pistons due to detonation- Built a few 215 Buick engs for minirods & they never burnt any valves although over the years a few lifted the heads{ think it was the 6/71 blower pumping 32 lbs of air did that😄 }..My tank ran on 80/85- but was radial that was meant to run on that octane.:Neighbor ran 115/130 in sand buggy{VW eng} in Az-[he could still get it in old Mexico]W/ no problems.---P.S. found pic of twin 215's

firpitch - What grade of Avgas are you talking? 100 octane? The current types are 100/130 (green) which has 4 gms of lead per gallon .. 100LL is low lead (blue) 2 gms of lead per gallon .. and the new 82 octane (red) is unleaded.
High octane fuel in the pony would have a tendency to burn valves and pistons, I'd expect, as there's no way to advance the spark to take advantage of the higher octane rating. The leaded gas will benefit valves to some degree, but lead fouling of spark plugs could become a problem.

That I would agree with OzDozer on needing to advance the spark? I guess my thought is that the fuel should burn in the allotted time period prior to the valves opening. The fuel is a higher quality in my way of thinking so it should burn fast enough. I suppose that there would be residual heat that could be used for power that would be instead heating the valves. So maybe OZ is on the right track. 😕
I guess I would only then reply that the time period of running the Pony probably wouldn't hurt (Maybe?).
If its free, then run it, if I was paying more for it, then I wouldn't do it.

I had a d8-8R for a while. I tried using the 100 low lead (blue) in the pony motor. What I found out was that the compression was to low for that high of an octane fuel and the motor was hard to start. I also found that out on my snowmobile.

adding a mix, say 30 % 100LL and 70% 87 auto gas will give the added lead the old engines were built for. Then you would have to ask yourself if the lead is a benifit in a pony enging that almost alwayse runs cold.

on a side note Old avgas seems to mantain its quality better than 87 auto gas. IMHO

If you check around with various fuel distributors I think you'll find a few who still sell premium gas w/o the ethanol in it. They'll fill gas cans but will not put it into a vehicle's fuel tank.

Thanks for all the replys. I think I will keep on using this fuel. It is the blue 100 octane fuel. Tanker, that looks like the Olds valve covers on the 215. I have one of those engines. They have the extra head bolt per cylinder, but then you already know that. If I buy diesel fuel out side of the city, I can still get it without biofuel added. Offroad fuel still has sulfur in it but that probably won't last long. I have had fuel pump problems with the low sulfur hiway fuel in the Cat 1160 and have been using Lubribor as an additive.

Av gas is very good fuel period.....

Is it bad and will it burn valves/pistons,,,, no...

Any advantage to running it in our old engines, no not really, the lead is 100 times less than was put in the fuel when these engines were produced. The small amount of lead won’t really help.
In the old days people all warned that burring unleaded fuel in old engines would burn valves, well as it turned out unleaded has been easer on our old engines than leaded was.

When is Av gas GREAT,,, When you have the compression that you need it to prevent predetanation, then it's GREAT stuff!!

It also smells much better than unleaded and as some have said, it lasts much longer before the octane starts decreasing.

Happy Running..

Paul the Buggyman