Lead in gasoline was a stop-gap solution. If I remember correctly , it was added because we didn’t have the technology at the time to refine gas sufficiently to get the octane levels necessary to prevent pre-ignition of fuel (which causes rod knock) at a reasonable cost. Tetraethyl lead effectively increased the octane level/resistance to pre-ignition. As a side benefit, the lead slightly lubricated the valves and valve seats so that they lasted for tens of thousands of miles, instead of needing to be reground every few thousand miles.
It was a stupid stop-gap though, esp. since the dangers of lead were well known by then.
You’re mostly correct. It was an additive to raise the octane rating and did lubricate. However, it wasn’t a gas refinement issue that caused the need. An octane boosting additive has been needed ever since, right up to today. Now the octane booster used is ethanol, mostly.
Race cars and many airplanes still use lead. We’re still making people dumber. Just at a lesser scale.
While it’s no consolation to these current people, they are trying to make the switch to lead-free aviation fuel. It’s partly a regulatory nightmare, and partly a genuine safety challenge; mandating a fuel change in aviation without adequate research and understanding can result in unexpected engine malfunctions.
On the other side of that is the known problems that lead causes. Seems to me that the best solution is to give everyone a cut off point, and say, hey, when we hit this point, you’re going to have to retire that engine, and get one that’s known to be good with lead-free avgas. Sure, it’s a cost, but that’s why you give people time to prepare.
You can absolutely get high octane ethanol-free gas; there’s a place near me that sells it. I know that a lot of people with motorcycles use it, because inline four cylinder motorcycle engines tend to be high compression, and motorcycle people tend to be almost religious about not using ethanol. (Which is unnecessary; assuming your motorcycle is fuel injected, the only risk with ethanol is storage for several months at a time with a full tank of gas. If you do that, then you’re going to end up with water in your gas, because ethanol is hygroscopic. As long as you keep riding regularly, or empty your tank and run the motor dry before storing it for more than a month, you’ll be fine with ethanol in your gas.) I know of at least once place near-ish to me that sells 110 octane ethanol- and lead-free racing gas. Ethanol-free high octane fuels tend to be about 25-50% more expensive than fuels with ethanol.
Avgas is another story. The odds are pretty good from what I can tell that any prop airplane is going to need gas with tetraethyl lead. To me, that sounds like a good reason to remove them all from service in favor of jets, but I think that jets have a higher stall speed, which can be a problem, esp. in backwoods areas.
(Jet-a and jet-a1 are kerosene derivatives, and don’t have lead.)
Ethanol free gas doesn’t mean there aren’t any no knock additives. There’s several more things besides Ethanol that can be added to gasoline that will increase the octane. Strictly speaking, “gasoline” isn’t even one exact formulation.
Short of it is that ethanol free gas just means it’s using something else to boost the octane.
You misunderstand. Before tetraethyl lead was removed from gas–in the 70s, I think?–engines were not nearly as good as they are now. My dad was doing really, really well to get 100,000 miles out of a car in the 60s and 70s; you used to see a service station attached to every single gas station, because of how much service cars needed. Now, 200,000 miles is close to the minimum that people would expect with only preventative maintenance. It’s nearly unheard of for people to need to replace valves and regrind valve seat now, except for high compression, high RPM engines (esp. supersport motorcycles). But that was just normal before the mid-70s. My dad has done multiple full teardowns on engines before the 80s, replacing head gaskets, piston rings, valves, and so on. These days that’s almost unheard of.
I think that the most intensive valve maintenance that I’m aware of that’s common right now is cleaning carbon off for some of the direct injection engines. I know that it’s an issue with Volkswagon cars, but most cars don’t do DI. You’d have to check technical service bulletins (TSBs), but most cars are very trouble free compared to what you could expect prior to the 80s.
Lead in gasoline was a stop-gap solution. If I remember correctly , it was added because we didn’t have the technology at the time to refine gas sufficiently to get the octane levels necessary to prevent pre-ignition of fuel (which causes rod knock) at a reasonable cost. Tetraethyl lead effectively increased the octane level/resistance to pre-ignition. As a side benefit, the lead slightly lubricated the valves and valve seats so that they lasted for tens of thousands of miles, instead of needing to be reground every few thousand miles.
It was a stupid stop-gap though, esp. since the dangers of lead were well known by then.
You’re mostly correct. It was an additive to raise the octane rating and did lubricate. However, it wasn’t a gas refinement issue that caused the need. An octane boosting additive has been needed ever since, right up to today. Now the octane booster used is ethanol, mostly.
Race cars and many airplanes still use lead. We’re still making people dumber. Just at a lesser scale.
If you want a sad rabbithole, look at the cancer rates around small airports, which are often much closer to where people live.
While it’s no consolation to these current people, they are trying to make the switch to lead-free aviation fuel. It’s partly a regulatory nightmare, and partly a genuine safety challenge; mandating a fuel change in aviation without adequate research and understanding can result in unexpected engine malfunctions.
On the other side of that is the known problems that lead causes. Seems to me that the best solution is to give everyone a cut off point, and say, hey, when we hit this point, you’re going to have to retire that engine, and get one that’s known to be good with lead-free avgas. Sure, it’s a cost, but that’s why you give people time to prepare.
They have! 2030.
I’m not sure if it’s a mandate, or a goal, but it’s there.
You can absolutely get high octane ethanol-free gas; there’s a place near me that sells it. I know that a lot of people with motorcycles use it, because inline four cylinder motorcycle engines tend to be high compression, and motorcycle people tend to be almost religious about not using ethanol. (Which is unnecessary; assuming your motorcycle is fuel injected, the only risk with ethanol is storage for several months at a time with a full tank of gas. If you do that, then you’re going to end up with water in your gas, because ethanol is hygroscopic. As long as you keep riding regularly, or empty your tank and run the motor dry before storing it for more than a month, you’ll be fine with ethanol in your gas.) I know of at least once place near-ish to me that sells 110 octane ethanol- and lead-free racing gas. Ethanol-free high octane fuels tend to be about 25-50% more expensive than fuels with ethanol.
Avgas is another story. The odds are pretty good from what I can tell that any prop airplane is going to need gas with tetraethyl lead. To me, that sounds like a good reason to remove them all from service in favor of jets, but I think that jets have a higher stall speed, which can be a problem, esp. in backwoods areas.
(Jet-a and jet-a1 are kerosene derivatives, and don’t have lead.)
Ethanol free gas doesn’t mean there aren’t any no knock additives. There’s several more things besides Ethanol that can be added to gasoline that will increase the octane. Strictly speaking, “gasoline” isn’t even one exact formulation.
Short of it is that ethanol free gas just means it’s using something else to boost the octane.
You’re getting something done to your engine every few thousand miles?
You misunderstand. Before tetraethyl lead was removed from gas–in the 70s, I think?–engines were not nearly as good as they are now. My dad was doing really, really well to get 100,000 miles out of a car in the 60s and 70s; you used to see a service station attached to every single gas station, because of how much service cars needed. Now, 200,000 miles is close to the minimum that people would expect with only preventative maintenance. It’s nearly unheard of for people to need to replace valves and regrind valve seat now, except for high compression, high RPM engines (esp. supersport motorcycles). But that was just normal before the mid-70s. My dad has done multiple full teardowns on engines before the 80s, replacing head gaskets, piston rings, valves, and so on. These days that’s almost unheard of.
I think that the most intensive valve maintenance that I’m aware of that’s common right now is cleaning carbon off for some of the direct injection engines. I know that it’s an issue with Volkswagon cars, but most cars don’t do DI. You’d have to check technical service bulletins (TSBs), but most cars are very trouble free compared to what you could expect prior to the 80s.
Very interesting, thanks for the reply.