just came up today at work (i fix airplanes): i have access to a lot of avgas for free, drained from aircraft and technically not legal to put back in to said aircraft. it is 100 octane leaded gasoline, which i'll be running in my camaro (currently non-cc carb'd stockish 305). i'm planning to build a 350 or 400 and am considering the tuned-port injection route. what effects will leaded gasoline have on fuel injected engines?

i searched the forums first, nothing came up... although i can't imagine this hasn't been discussed before. search button broke?

and please, please stay out of the discussion if you are going to say stuff like "you should never use leaded gas. ever." without backing it up with evidence or at least solid reasoning. thanks

 

Lead deposits will kill your O2 sensor.

 

And your cat.

And the trees. Don't forget the %&$*ing trees. They make oxygen, both you and your engine breathe oxygen. Your engine is happy when it breathes oxygen. Trees == Happy Engine.

 

The car will at least still run fine with a cat full of lead. The O2 sensor you'd know about within a few thousand miles.

And the trees won't mind too much, but it'll make the neighborhood kids grow up stupid.

 

ah right... the o2 sensor. thanks for the quick reply. scaryone, when you said cat didja mean the animal or the exhaust part? :P

 

It'll kill both.

 

O2 sensor? On a non-CC carb?

 

He asked about fuel injection.

 

He said planning to build, maybe FI.

Funny we're worrying about trees when a lot of that fuel is being burned anyway. If its that much of a concern, get the fuel banned entirely.

I say burn it.

 

i used to be in same situation . [ fixed wing ] my old p/u with carbed 396 loved a 50/50 mix of regular and 110 LL . just my experience with a carb. engine . don't let it go to waste .

 

There's a good deal of research on the effects of lead on engines, mostly in the aircraft industry, including valve seat wear, valve stem wear, lead fouling of plugs, ring land problems, cylinder wear, exhaust corrosion, oil contamination, all sorts of nasties, dating back into the 1930's.
Ever wonder why in cars running leaded gas 60K mjiles was considered good, while today unleaded engines can go 300K + ??
On a FI engine, you *can* run leaded if you stay strictly open loop, as lead will quickly kill an O2 sensor, and it *may* kill whatever you use ( wide band or narrow band ) temporarily installed just to get it tuned.
Lead will quickly kill a catalytic converter as nothing more than added back pressure, as it coats the catalyst and renders it moot. ( and destroys its scrap value )

If this is a race engine, rebuilt after each season, and you need the anti-knock characteristics of the 100 octane rating, AND it's legal to run it in those races, I'd run it.
I'd certainly run it in my lawn mower. ( free vs $3/gal pump ? )
If this is for your daily driver, go to work camaro, that you plan on keeping for years, I would not consider it a realisticly viable alternative to unleaded pump gas.
But, that's just me.........

 

also, av gas is formulated to run in steady rpm engines, and i'm sure vapor lock is a big concern, depending on what part of the country its from.
i've used it before in a carbed application, and never noticed a difference.

 

Sometimes, my eyes read faster than my brain. . .

 

Well, my thing about the trees was the lead fumes in the exhaust, something that's virtually guaranteed not to be in unleaded gas.

Oh, and I dunno what mods you've done, but in auto class we tore apart one kids Hon-duh, and he was running av gas on stock internals, and one of his exhaust valves had almost cooked away. O.o

 

That's funny, usually unleaded gas is harder on valve seats than leaded gas is - hence the 1968 cylinder head typical problem eh?

 

I don't think that exhaust valve was suffering from the lead. More from the increased exhaust temps from burning the 100 octane plus lead. The stem on it was all the way down to 1/3 or 1/4 of the width of the rest of the stem. I'm amazed it didn't snap off in his engine.

 

yeah it definitely won't be my daily driver... maybe one day a week. as far as the trees/retarded kids are concerned... i'm convinced the stuff they put in unleaded gasoline to make up for lead is just as bad or worse. although this assumption is based solely on the way it makes my eyes water and throat burn, and on no actual research whatsoever
anyways i'm still in the early planning stages for my mean machine, so i should have lotsa time to figure out this whole business. thanks for the responses

 

And the fact that it leaches into groundwater so easily!

 

yeah but who drinks ground water anyways... i mean unless you are drinking DASANI

 

If you got no 02 or CC ...... you, yourself wont kill and trees or tree huggers running it, just aslong as everyone in the world dont use it i think we will be ok lol..... here is what leaded gas did for cars

Pre-1971 engines were equipped with "soft" valve seats and leaded gasoline acted as a lubricant to prevent excessive wear of the valve seats and what not in the system

 

No offense, but "soft valve seats"? I'm calling flat out BS. Leaded gas raised octane for cheap. According to Wikipedia:

 

It's not entirely BS. Heads built for unleaded fuel only have hardened seats to prevent wear and valve recession. TEL stakeholders made a big deal out of it when it was scheduled to be phased out entirely, saying that banning leaded fuel entirely would destroy engines. That hasn't been the case though since accelerated valve seat wear is really only an issue for high performance use.

 

For all of the tree huggers/ground water drinkers/future parents of stupid kids, let me say this much: This leaded gasoline was to be burned in aircraft engines just like millions of gallons are every day. Most smaller countries still use leaded gasoline to this day in CARS!!! (GASP!)
Guess where all the lead came from that was ever put into a gallon of gas?
The moon? Outer-freakin'-space? No, every bit came from the earth.
So if you've been riding the environmental short bus for so long that your concience won't allow you to burn it in a car, donate it to your local dragstrip and take it off of your income taxes, or sell it to me for $2 per gallon and I will dispose of it for you in THIS.
It even has "soft" valve seats in '68 model HEADS.

 

Wikipedia as a defense? lol.

Get some background before you raise your flag.

 

if there is a mechanic from the 50's around he will tell you that the soft valve seats was the MAIN reason for it

 

Okay, I raised my flag, and was wrong. But I did read through some of the references (those that would seem to have automotive information) in Wikipedia's bibliography for the TEL entry, and saw nothing about valve seats. I was wrong, and I am sorry I called my BS flag. But I do believe that the hardened valve seats wasn't the primary use of lead in gas. Lead directly boosted octane, and you didn't have to add very much lead at all.

Oh, and Supervisor42, when was the last time you went out and picked up a piece of lead from the earth and ate it? Probably never. You don't really have a choice when you breathe air that has lead in it. It's not so much a tree hugger thing, as lead doesn't matter much to dirt, but to a human it is a known poison.

 

He'd be wrong, though. Antiknock properties were the main reason for the addition of TEL, the protection of the valve seat was an added bonus. In fact, lead scavenging chemicals had to be added to the "Ethyl" additive to remove excessive metallic lead after combustion to prevent it from fouling the cylinder.

 

My, but you are the "scary one" aren't you. I guess we better tell all of those planes not to take off tomorrow...
I do agree that we don't need lead in automotive fuel any more.
I guess we don't need hydrocarbons either. (oh wait, there's the Al Gore alarm again)
While you're at it, fire up the C0˛ / global warming argument.
Will it finally end when they pass a law that we can't exhale because we breathe out...*gasp* C0˛?
I don't think so. I think it will end when they outlaw us drinking water because it is in such short supply...
(fortunately, I like beer)

 

I agree about the main reason being octane/anti-knock. Cheap octane additive. However, as to the seats... any head you buy nowadays or the factory ones once unleaded came into play have hardened valve seats on the exhaust at the very least. There's no reason for them to spend extra money if they didnt need it, the lack of lead was a direct cause for putting in hardened seats. I've seen the damage firsthand too, many times, and repaired it with new seats.

As for the political argument, like I said before, get it banned completely if it concerns you. The stuff the guy is getting is either being used by someone else or its getting canned and buried so he may as well use it. Also seems to me that during the heavy usage of said lead, people werent exactly dropping like flies and this stuff is LL so there's barely any in there anyway. There are a lot more important things to worry about if you're worried about the enviroment (and yours around you).

 

I have a well.

Pretty much everybody out here does.

 

Just don't bathe in the stuff (lead can be absorbed through the skin), and don't inhale the exhaust and there's little to worry about.

No, not dropping like flies, but the human body doesn't eliminate lead efficiently, and lead lasts for a long time in the environment. Soil samples taken near roads continue to show elevated lead levels, despite lead being eliminated for highway use over 20 years ago. Once you ingest it, lead has a 25 year elimination half-life in your body. Most of it gets stored in the bones, where it can be re-released into the bloodstream later in life. Children are more sensitive to the effects of lead, and usually have a higher soft-tissue concentration after ingestion because their bones are smaller.

 

and as far as lead causing brain damage to people, look at the folks who were around while leaded gas was being used. then look at the kids today, and think where the world will be in 20 years when they're the ones running it. i think television is causing more brain damage than any amount of lead. heck my chem teacher in high school told us he used to eat the lead paint off his bedposts as a child, and he was (mostly) fine.

 

I agree completely. Some of these kid shows nowadays look like they were written by a schizophrenic.

 

That's only because the kids today are being raised and educated by brain-damaged, lead-poisoned adults.

 

hahaha, this is hilarious, nice to see some good humour going around every once in a while here eh?
I remember chewing lead pellets from a BB gun back in the day... I did make it through high school actually...

I love this point, I like to bring this up a lot defending my line of work when I get "schooled" about working for "an evil corporation" (a company which packages natural gas compressor stations.

I just say "You don't like using a fossil fuel like natural gas? Ok, lets cut you off - turn down your thermostat, and watch you freeze in the dark". Not many hippies up the cold climate, they'd rather burn the fuel and stay warm - it's the folks in the warm areas that worry me, they got nothing to lose
All the DIESEL burning is what bugs me, that stuff leaves TONS of crap in the air (granted it's mostly harmless soot), but all the work trucks that idle 24hrs/day? Yep, i'm more worried about those than my hotrod.... (for the 3 weeks a year it actually runs).

 

i agree with apeiron. I mean its been around b4. One person aint gonna hurt, but w/e floats ur boat. Smoking ciggarettes and drinking alcohol will hurt you too, but it isnt outlawed.

 

The whole point of leaded gas was a *cheap* way to boost anti-knock characteristics of gasoline. Way back when, pump gas carried an octane rating of about 60. In order to use higher compression engines, higher octane was ( and is ) required. TEL interferes with the pre-combustion recombination of hydrocarbons in the end gasses, reducing the tendency to detonate, allowing normal burning to take place. At one time, I used to know whether it was the long chain hydrocarbons breaking down into short chain HC, or the reverse, but an old man's memory sometimes fails. In any case, it works to that end, and works very well. Very small quantities of TEL produce rather large increases in anti-knock characteristics, allowing high compression without detonation. TEL wasn't the only way, bt it was a cheap, practical, and low cost way.
The whole toxicity argument has been blown WAY out of proportion. It has some merit in the parking lots of the Santa Monica freeway, and the DC beltway, but not at the drag strip.
The *real* purpose of the elimination of TEL from motor fuels is to allow the use of catalytic afterburners...... er..... "converters" to complete the combustion of unburned HC and CO in the exhaust as well as a significant reduction in the highly toxic NO. In the parking lots mentioned, with hundreds of vehicles ideling for hours in all sorts of states of poor tune it's a significant improvement in reducing bad air. For a weekend warrior it's hardly worth mentioning, except that government gets involved.
We can argue about whether or not "oxegenates" are for improved combustion ( no ) or simply a converter-safe substitute for TEL ( yes ) or a plot to enhance the bottom line of Archer Daniels Midland Corp. ( yes, IMHO ) all day long, but that's politics, not performance.

Were I putting together a modified big block Firebird "toy" to go play one or two days a week, would I put together a 14/1 compression mill that *required* leaded very high octane fuel, or straight alky fuel, just to play ? For me, I would not. For me, I'd put careful attention into building the thing to extract maximum performance on commonly available pump gas.
Now, if I *knew* that this 100 octane av-gas would be available to me for the life of both myself, and the vehicle, AND the vehicle would neither have cats, nor run a closed loop FI system, yeah, I would build it that way, and enjoy driving it without a second thought.
Politics aside, for a "toy" I say go for it ! For a daily driver, I still think it's a bad idea.
There's a whole lot of politics, rumor, and opinion on catalytic converters, leaded gas, and about every aspect of performance engines, but with internet today, it's not THAT big a deal to read the history of gasoline, WW1 fighter aircraft, chemical reactions of gasoline combustion, etc. and reach an informed decision.
One hot rod will make about as much difference as one flea on an elephant.
It's your money. Make your plan, research your options, advantages, and disadvantages, then do what you want to do, and have fun in the process.
Respectfully submited rambelings of a malcontent.

 

I guess I'm one of the stupid's from the 50's poisoned by useing leaded gas!
(so what?). Let's take a look at all the other stuff. No more fishing! (lead weights) No more hunting (lead shot) No more tire balancing (lead weights) No more flying anywhere (Leaded fuel).
By reading some of these post here, It's TOO LATE! Your all damaged already.

 

Did I ever say it was right for planes to use leaded fuel? Did I ever say it was right for factories to spit out more unburnt hydrocarbons than all of our cars do in a year in a day? Did I ever say it was safe to eat rabbit that you shot with lead shot? Did I ever say that I liked the idea of nasty old high-emissions diesels spitting out soot 24/7? I did not. It happens, but should it? Not really. But hey, we're gonna blow up the world here in a few years, so, burn it if you got it. :yes:

Hey, supervisor, why don't we BURN living KITTENS to light boilers to power our cars? I mean, they're just kittens. They come from the environment and can make energy. So let's BURN them. It'll eliminate fossil fuels. You just gatta clean out the burner on stops. You can even have your kids eat the crunchy leftovers! Two birds, one stone!

 

i like that idea... why arent we burning kittens.... oh wait there aint enough of them... now rabbits... you know how they are...

scary... why dont you stop playing with cars, and start building that bombshelter you are gonna need when we do blow this planet up... that way you will be one step ahead of the rest of us...

 

If it's good enough for airplanes it's good enough for a small block. Just watch the octane. Not sure if it's the R+M over 2 rating or something else. Used to run it in my old Harley, wouldn't tolerate low octane unleaded at all, and I mixed it with regular to get the octane down to stop bluing the exhaust pipes. That's probably what happened to the Honda's valves as mentioned above. Hard to beat free gas, whatever it is!