ok, here goes, but I am by any means an expert.

It was mentioned earlier that AV gas is leaded. This rang a few bells and I am now able to recall a conversation with a pilot that I know. Leaded fuel runs cooler than regular pump gas. This is mainly ( I would guess) because airplanes run at a consistant RPM for long periods of time and in the process building heat. The leaded fuel helps the engine run cooler in these circumstances.

As far as running the fuel in a 4-stroke ATV, where the RPM's are up and down significantly more than a plane, the engine doesn't build the heat, and may result in what 2-stroke fans know as a "cold seizure".

I would also have to believe that the motors of today are designed to run on the formulated pump gas so they run cleaner (less deposits). Add lead to that fuel and you could run into a lot of build-up in your combustion chamber and in your valves. Even possibly causing a valve to stick and causing several hundred dollars of internal damage to your engine.

In the end, I will sum it up in saying that your motor will not reach optimum operating temps and coupled with the build-up of deposits in your engine, you will never reach peak performance.

As I said, I am no expert in this field and this is only what I would suspect the consequences would be for running avgas. If I am wrong, someone please correct me.

 

Pump gas was leaded for years, and ran in 4-stroke engines without problems. Lead in avgas can clog a catalytic converter, but our wheelers don't have any. The lead doesn't actually make the engine run cooler, it simply suppresses detonation, which is a known engine killer. If anything, the lead would promote longer engine life, since it is a cushion to valve seats and actually acts as a lubricant to cylinder walls and piston rings. In my 2-stroke engine, it actually reduces piston rattle with the forged piston I am running. Avgas leaves less deposits in an engine than pumpgas. As far as the engine not getting up to temperature on avgas, if your cooling fan cycles, then your engine is up to operating temperature. Avgas can make an engine run richer (cooler), but that is because it is a different formulation of fuel, so one must jet leaner. I say jet for avgas, and everything will be fine. Avgas is also much more stable and consistent. And as for avgas being a fuel for high altitude engines, what about when the plane engine needs to make the most power, during takeoff.........where is the plane at then..........on the ground. I have jetted for the avgas, and my engine runs super.

 

thanks for the info walexa. But I have to ask you why you did not enlighten everyone on your knowledge of this before any of this alleged false information was posted?

Yes, years ago engines ran on leaded gas. But engines are now different than they were years ago also.

You mention that the lead actually "cushions" the valve seats. In order for this to happen, then lead "deposits" have to be in place. Wouldn't a build-up of these deposits lead to valves sticking? Sure it may take some time. But to me, if it is something that can be avoided, then why not just run on the cheaper, cleaner, pump gas? Where are the benfits of running avgas?

Thanks for your info.

 

My knowledge on avgas is limited, however, many people come down on it without sound proof. In other words, most people run off of hearsay..........

I wasn't trying to ask a question that I already knew the answer to.......because I don't have the answer. I just want some factual information other than the typical responses about altitude and so on.

Let's talk about deposits: If you have ever torn down an engine, you have probably seen carbon on the piston, and around the valves. Carbon is destructive to valves and their seats, and everything it comes in contact with. The lead in the avgas is like oil in my 2-stroke gas, just because it lubricates the cylinder and rings, doesn't mean it builds up. Same way with the lead, just because it cushions/lubricates doesn't mean it will build up.

I've only started running it on my last rebuild, so I will know more about it and it's longterm affects on my engine in a year or so. I have read from reputable sources about the information that I do have. As I've stated before, I just want factual information or personal experiences with avgas.