Leaded Gasoline

[Guest]

I recently had trouble with my 67 mustang and when i took it to a mechanic he mentioned using a lead additive because in his opinion old motors needed it. So my question is my 74 has no cats or anything and still has the big fuel opening so should i do the same with it?? Plus i found a place by my work that sells leaded gasoline for "off-road" use. But here in oklahoma there arent even inspection stickers so other than the legal reasons why shouldnt i just use it??? I guess im just wanting to know a little more about where u can or cant use leaded gas and if its a good thing. thanks!

 

[67ster]

Yeah , leaded gas is still available but pricey . Aviation fuel or race gas . I think it is better to have the heads reworked for unleaded .

 

[67686977]

What makes you think you are buying "leaded" gas. There are plenty of people selling premium gas at best and claiming that it is the old leaded gas. Don't buy it. If yoy think you need more lead, shoot your car.

 

[BroncoJAK]

Older engines used the lead as a lube for the valve seats. You need hardened seats installed in your heads. If this hasn't been done by now,(35 years later ), problably time for a rebuild anyway.

 

[badnewsbronco]

i 've got a 68 with the oridgnal 6-170 in it and i only put about 250 miles a year on it . i put a half a can of lead adative per full tank and it seems to make run a little better i also put it in my snowmachine and dirt bikes it really makes a diffrance in them, yea theres the invirmental issues but what are ya gona do

 

[edjolly]

Run unleaded until the valves die (this will take quite a while) then rebuild. Run it a little rich and they'll last longer.
A '71 Ford p/u I had with a straight six is still running strong on unleaded 7 years after I bought it.

Ed

 

[Broncobowsher]

Leaded fuel was a good additive to minimize valve seat recession. When lead went away, they hardened the valve seats to do the same thing.

Valve seat recession occurs when an engine is run hard for long periods of time, like an airplane or boat that is run wide open for hours on end.

It is not really a problem with ordinary passenger vehicles. Full power is only used for very short bursts.

Valve seat recession is when the valves wear into the head and the valve sinks into the head. On old engines, it would require resetting the valve lash or the valve would leak. If it would leak bad enough, the combustion would cause it to burn through at the leak.

So, unless you enjoy towing big rigs up mountains, don’t worry about it. Most Broncos will overheat before they can be stressed that much.

Lead also does 2 other things, one is raise the octane. Which actually decreases power unless you advance the timing to take advantage of it, but that causes other problems. The other is a polluting factor. It put lead into the environment. It gets on everything from the sparkplugs and causes you to need to replace them sooner. It is also gets into the blood and causes lead poisoning. That is another reason that it was banned from gasoline.

Now that I have been on my soapbox about lead, let my kick it out from under myself. Do I use lead? Yes I do. I run 80/87 AV gas in my boat. It is an old original engine that I run at full throttle a lot. The lower octane of the fuel promotes a faster flame speed, which gives me more power. I picked up 200 RPM on the top end by lowering my octane. I also use 100 octane LL (low lead) in some of my other toys. I use it because it doesn’t have any alcohol and is more stable when stored. I will pay the price in sparkplug life, but in those toys, the plugs get replaced due to fouling more often then anything else.

I could go on for a long time about this subject, but I will quit now. As for the fuel I would run, just straight 87 octane Oklahoma pump gas. If you are going to store it, for more then 3 to 6 months, use 100 octane AV gas and some stabilizer.

 

[74bronc]

[quote author=Broncobowsher link=board=5;threadid=14480;start=0#109154 date=1045837157]

Do I use lead? Yes I do. I run 80/87 AV gas in my boat.
[/quote]

Can you still get 80/87 out there? I haven't seen that stuff for years. The only thing we have out west is 100LL at the airports, or at least from what I've seen in the last 3 years that I have been flying.

 

[Jeep Slayer]

I have had no real porb runnibg unleaded in eather my 65 stang or the Bronco just run it til the motor dies of pld age and then build it for the unleaded stuff next time

 

[Broncobowsher]

[quote author=74bronc link=board=5;threadid=14480;start=0#109165 date=1045839943]
[quote author=Broncobowsher link=board=5;threadid=14480;start=0#109154 date=1045837157]

Do I use lead? Yes I do. I run 80/87 AV gas in my boat.
[/quote]

Can you still get 80/87 out there? I haven't seen that stuff for years. The only thing we have out west is 100LL at the airports, or at least from what I've seen in the last 3 years that I have been flying.
[/quote]

I have found it only at the city pump at the Chandler Airport. The bad part is that it is the most expensive gas to buy. Last time it was 50¢ a gallon more the 100 LL. But that low octane runs great in a 6.8:1 compression engine

 

[lars]

[quote author=74bronc link=board=5;threadid=14480;start=0#109165 date=1045839943]
[quote author=Broncobowsher link=board=5;threadid=14480;start=0#109154 date=1045837157]

Do I use lead? Yes I do. I run 80/87 AV gas in my boat.
[/quote]

Can you still get 80/87 out there? I haven't seen that stuff for years. The only thing we have out west is 100LL at the airports, or at least from what I've seen in the last 3 years that I have been flying.
[/quote]

There are a few airports, mostly the ones known as hobby or enthusiast airports that carry 80/87. Last time I flew into Santa Paula airport in Socal they still had it. 100LL has a lot more lead in it than most car gas did (not sure how it compares to some of the older car gas brands like Sunoco). The plugs in the Continental O-200 I flew behind for years (I was partners in a Cessna 150) hated lead, and on long taxis it often required a full power runup to clear them. The Lycoming O-235's in the Cessna 152's I learned to fly in were even worse. We had an autogas STC for the C150- it ran great on high octane unleaded car gas, seemed smoother than with the leaded stuff. Also the oil would be cleaner. But we were always nervous about flying with it in hot weather because of the risk of vapor lock. Pretty scary when the prop stops turning...

 

[74bronc]

[quote author=lars link=board=5;threadid=14480;start=0#109251 date=1045854353]
[quote author=74bronc link=board=5;threadid=14480;start=0#109165 date=1045839943]
[quote author=Broncobowsher link=board=5;threadid=14480;start=0#109154 date=1045837157]

Do I use lead? Yes I do. I run 80/87 AV gas in my boat.
[/quote]

Can you still get 80/87 out there? I haven't seen that stuff for years. The only thing we have out west is 100LL at the airports, or at least from what I've seen in the last 3 years that I have been flying.
[/quote]

There are a few airports, mostly the ones known as hobby or enthusiast airports that carry 80/87. Last time I flew into Santa Paula airport in Socal they still had it. 100LL has a lot more lead in it than most car gas did (not sure how it compares to some of the older car gas brands like Sunoco). The plugs in the Continental O-200 I flew behind for years (I was partners in a Cessna 150) hated lead, and on long taxis it often required a full power runup to clear them. The Lycoming O-235's in the Cessna 152's I learned to fly in were even worse. We had an autogas STC for the C150- it ran great on high octane unleaded car gas, seemed smoother than with the leaded stuff. Also the oil would be cleaner. But we were always nervous about flying with it in hot weather because of the risk of vapor lock. Pretty scary when the prop stops turning...
[/quote]

Yes, I know the feeling all too well. I did my BFR in december in a C-182 and the first time I pulled the carb heat on in the air, I lost all manifold pressure. You know that when you get the look of death from the CFI, you are in trouble. Luckily we turned the heat off and got MP back. Didn't make my heart stop beating fast though... I fly my dads C-172 w/O-300 Continental and it runs great on 100LL. We have the autogas STC for it but haven't put autogas in it yet.

Sorry for off-topic... ;D

 

[Guest]

k thanks guy i learned more about lead than i know what to do with. i might just put a lil lead additive in it every now and then till it dies. thanks again

 

[Explore74]

since we are off the orig. topic a little bit, I'll throw in my 2 cents. I used to race karts, and I required 95+ octane for the engines I ran. I tried the 100LL, and learned the hard way that the stuff, although containing more lead than passenger vehicle fuel, was still some really dry fuel. I had to add stuff like 'bananna oil' and some trick 2 cycle oil to keep it from galling cylinders. After dyno runs using that fuel as opposed to other types, I found that for the money, I got better performance from Sunoco 98 race gas, than the 100LL. To make it even more cost effective, I mixed it 2:1 with Shell 94 pump gas. The Shell gas has fewer additives than most, and around here (West Texas), it was the only thing without ethanol added to it. If you want to get really trick, go to the chemical supply and get some tolulene and some xylene. Mix these two 50/50 and add 2 ounces to 5 gal. of the 98/94 mix, and watch the torque #'s rise. The tolulene/xylene slows the burn time, allowing a burn for more of the power stroke, thus yielding more torque. HP #'s remain virtually unchanged.