Is it necessary to Add Lead to the gas?

I'm sure this is something that has been talked about before. Wondering on older tractors if it is [b:db73cda88a]necessary[/b:db73cda88a] to add lead to the gas? I have a 1950 Super A and I have not added anything to the gas. Granted I have not run it a bunch since first starting it in July 2011 but wanted to find out from the experts....what do you think?

Short answer:
NO.

Long answer:
First off, you can't get lead to add to the gas anyway. You can get a "lead substitute", which is a kind of ill-defined concept. Tetraethyl lead had a couple useful properties it added to gas, which require separate additives if done with out TEL (octane increase, valve lubrication). You don't need to worry about either one.

All the lead substitute does is separate you from some of your money.

Great Jim thanks. It was the valve lubrication that I was concerned about.

most of these old tractors are not" worked" anymore for it to matter.doing yard chores or parades, lead is not nessesary. also the valve guides are getting lubed already just from being worn out on that old stuff. also they dont even get up to operating temp.if the tractor was used loaded all day long every day then might want to look into something.

A lot of those old tractors were all fuel they ran on distillate. Did Distillate have lead? Or did they get enough valve lubrication from the gas they started up on? What about diesels? What/how are their valves lubricated?

If your worried about the valves just run a little bit of ATF in your gas and that will do the job. Or if you like to spend $$ use MMO in place of the ATF. MMO cost 2 or 3 times as much as the ATF but does the smae thing as the ATF. 1 qt. to 5-10 gal of gas

When unleaded became required in the early 70's there were rumors about ruining the valves and that they must have hardened seats immediately. It never happened.

you can't add lead because you can't buy tetra ethyl lead.

don't waste your time worrying about it, or your money buying lead substitutes.

as the myth goes, old cars that used leaded gas would have warped valves with out lead,,,,well, my old car is still running o.k., until the valves and/or motor goes bad, i wouldn't worry about it,,,as stated, you wouldn't use tractor as much as a older car to worry about it until the engine shows sign needing rebuild...

forgot to mention, i needed some gas one day, had a gas can off to the side with some in it, poured it in, ran fine , then needed gas for 2-cycle motor, where is that gas i had set aside for it, guess where it went,,,, the 2-cycle gas has been mixed with synthetic oil, seamed to worked fine for regular motor, think i will expand my gas to other motors....

The lubrication from the lead was only beneficial
on the face of the exhaust valves and seats. That
is why hard valve seats give better life than the
softer material in the head. Far as valve guide
lubrication, it comes from the engine oil coming
down the guide, not the gasoline. Adding a bunch
of stuff to gasoline will only add to the carbon
buildup. IH sent out several service bulletins
back in the day, recommending the use of unleaded
gasoline to help overcome build up on valves AND
the use of low ash oils. This was prior to IH
introducing their own low ash oils. Problem was it
was very difficult to find. Some oils designated
for LP use were very low in ash at that time.

The way I look at it lead was crap. They used to add it to low quality gas to make it perform better. Back when all we could get was leaded gas it seems like engines used to need frequent valve jobs. My grandfather had a '59 Rambler that needed 3 valve jobs before 100,000 miles. When I was a kid we knew a guy that had an old Cat gas tractor, he would only run it on white gas.

My humble opinion is todays gas (except for the ethenol) is a much better product and better for your engine than the old leaded stuff.

The newest specification of gas/automotive oil (SN and Dexos) is almost as low in ash as IH Low Ash ever was. Diesel oil is still higher than IH's spec, but the number has been coming down for the new engine design for emissions.

karl f

OK, I posted a rather long and boring detailed description on this exact subject 3-4 months ago. I will give you the thumbnail here. This subject irritates me more than any of the other "emotional" subjects, like which oil, which spark plug, etc. You don't understand the chemistry and physics of combustion when you say lead is for valve lube.....you are mearly regurgitating shade tree mechanic BS.

TEL or Tetraethyl Lead was NEVER intended or added to "lube" the valves. In fact, additives were added later to REMOVE the lead buildup from the valves (do a search on EDB and EDC). TEL was used SOLEY to increase Octane rating cheaply for high compression engines. One needs to understand petrolium cracking towers, and what that is compared to pure distilation. Long chain hydrocarbons do NOT easily distill and gasoline used to be VERY expensive to refine. Cracking technology changed that. TEL reduced refining costs even more by allowing higher octane ratings with lower grade gasoline. Ah yes, yet another solution driven by the almightly dollar.

If anyone tries to tell you that lead "lubed" valve seats, I respectfully say to them "hogwash". Lead did more harm to the valves and spark plugs than it did good. Reason that valves would burn out was improper timing or fuel ignition. All resulting from low octane rating, NOT the absence of lead.

I will try to find my post from a few months back, as it detailed the chemistry and the physics behind TEL. Sorry guys, octane rating and timing is important in the life of valves and valve seats, NOT the presence or absence of TEL.

Last "hint" on this. For distillate or dual fuel tractors: Kerosene and distillate NEVER, EVER, EVER had lead. So, if lead was necessary to "lube" the valve seats, why was it not added to kerosene or distillate? Kero and distillate ran/combusts hotter than gasoline on many fronts and for many reasons. For those of you old enough to remember, there is a water injection system on old kerosene engines to cool down the combustion.

Still don't believe me? Read this: http://www.epa.gov/oust/cat/Section_2-Historical_Usage.pdf

PS. my background is in chemical engineering and physical chemistry. If you would like to debate this, I'll be happy to provide a phone number........I have never posted that before, because I am more proud of my farm upbringing than I am of my "credentials".....but this crap really irritates me.

PSS: Looks like most of the posts agree with me..............sorry to rant, this urban legend really get's my dander up.................

Livin the dream: my irritation is NOT with your question, which somewhere in the middle of my rant, I hope I answered clearly. It is directed at whoever suggested to you that you NEED a lead additive.

tell them to buzz off or give them my phone number pls. Haven't had a recent opportunity to deliver a good tongue lashing lately!

I am certainly not qualified to argue with you
about the lubrication of exhaust valve seats but
am only repeating what the IH co. told us. They
strongly recommended not using leaded gasoline to
reduce deposits on all combustion components but
mostly valves and spark plugs. They did however
recommend keeping a closer eye on valve clearance
setting on older gasoline engines that did not
have hard seats in exhaust. Any gasoline head from
about 1945 did have hard seats. I personally got
into a little disagreement with one of the local
fuel distributors who was selling our customers
his additive, showed him the service bulletins,
but he kept selling it. I also have no complaints
on today's gasoline except we are very limited in
our octane ratings available. I saw as much or
more gasoline go bad 50 years ago as I do now.

Pete, what you post is correct and I have no issues with. IH co. indicated that leaded gasoline DID increase plug and valve deposits. Valve lash is important. Once again, Octane and timing play the role here. Another factor I forgot to mention on burnt valves, is running a tractor too lean on the carb mixture. I would have to do some research as to the octane ratings of "white gas".

Heads without Stellite seats would wear faster on the valve seat, and that coupled with valve stem wear would change the lift on the valves. There is more to valve lash and lift than just how much fuel gets into the combustion chamber. I also agree that modern gasoline doesn't give us much choice in octane ratings.

Previous poster indicated that valve jobs were the norm on high milage engines in the "old" days, and this was due to lead build up. Later, lead purging agents were added to the gas to burn off the lead deposits. These agents were also referred to as lead scavengers.

In any case, I agree with your post and IH Co.

NO.

Dear Pete, Old Iron, Hoof Print, Rustred, Mr. Becker, OLD, CNKS, Tom A and Mr.Fleming

I just wanted to thank you all for your overwhelming response to my question regarding leaded gas. Let me reasure you when I say I will never even think about using lead in my old tractors. Hard as this may be to believe but I was asking for a friend.... I told him that I was quite sure it wasn't necessary but would do a simple check for him on the subject with people I knew wouldn't lead me astray.

Thank all of you again for the information. This site is a wealth of inforation and to all of you who contribute to answering questions and helping others, again......[b:05f46df0b6]THANKS![/b:05f46df0b6]

(quoted from post at 08:55:11 11/02/11) When unleaded became required in the early 70's there were rumors about ruining the valves and that they must have hardened seats immediately. It never happened.

Click to expand...

My friend has a 1976 Ford Econoline van that he has restored and customized over the years. He's always used this van to tow his travel trailers, all over the country. Works the old girl pretty hard.

It's has a 1978 351 Windsor engine in it, since 1978, and up until last year, it had the ORIGINAL heads with the soft valve seats.

Last year he finally had to replace the heads because they'd eroded away due to the lack of lead in the gas. That's THIRTY years of hard use.

(quoted from post at 05:36:29 11/03/11)

(quoted from post at 08:55:11 11/02/11) When unleaded became required in the early 70's there were rumors about ruining the valves and that they must have hardened seats immediately. It never happened.

Click to expand...

My friend has a 1976 Ford Econoline van that he has restored and customized over the years. He's always used this van to tow his travel trailers, all over the country. Works the old girl pretty hard.

It's has a 1978 351 Windsor engine in it, since 1978, and up until last year, it had the ORIGINAL heads with the soft valve seats.

Last year he finally had to replace the heads because they'd eroded away due to the lack of lead in the gas. That's THIRTY years of hard use.

Click to expand...

Your friend's 1978 Windsor would from the factory, have had induction hardened exhaust valve seats - designed to operate with non-lead fuel. Ford converted to hardened seats on the Cleveland, Lima and Windsor engine production lines in the early part of 1970. I dug out my copy of an article in Metal Progress magazine, 1973 issue, which detailed the hardening process.

Also included in the article is a graph of Fords durability tests (high speed and load) showing an exhaust valve seat recession of 0.080" in 10,000 miles with conventional seat material hardness and non lead fuel - hence the justification for hardened seats. The same test conducted out to 50,000 miles confirmed the hardened seats on non-leaded fuel had less exhaust valve seat recession than the conventional seats on leaded fuel. Exhaust valve seat recession is due to locailized welding at asperities due to high unit loading. The lead in the fuel provided a thin protective film that prevented the welding and resultant wear. The hardened seat material works without the need for lead since the hardened cast iron (martensitic structure) is much stronger and better able to resist the welding/wear.

Several things to note here: 1) these were cast iron engines and did not use separate valve seat inserts, 2) the durability test was high speed and load designed to turn on the problem, 3) Engines that do not operate at high speed and load as in tractor engines, are unlikely to be subject to significant exhaust valve seat recession, 4) engines using separate valve seat inserts may not be subject to exhaust valve seat recession depending on the material used.

Ken, interesting information, and I have seen some of those studies myself. Low RPM, low compression engines are definately less prone to valve seat errosion. My point still is that TEL was NOT added to gasoline to reduce valve erosion. The fact that it is an observed by-product of lead being in the fuel is a fair statement. however, with the addition of lead scavengers designed to "burn off" lead, I would question the residual effect of any lead in the gasoline. Lead oxide, which is a by-product of combustion is fairly lubricative as a compound but causes vavle failure due to deposit buildup. Lead bromide/chloride, which is the by-product of combustion in the presence of typically used lead scavengers, not so lubricative and exits with the exhaust gases. Essentially, a "chicken or the egg" debate.

Here is an excerpt from a combustion analysis:

[b:b373bf43f3]A feature of TEL is the weakness of its four C–Pb bonds. At the temperatures found in internal combustion engines (CH3CH2)4Pb decomposes completely into lead and lead oxides and combustible, short-lived ethyl radicals. Lead and lead oxide scavenge radical intermediates in combustion reactions. This prevents ignition of unburnt fuel during the engine's exhaust stroke. Lead itself is the reactive antiknock agent, and TEL serves as a gasoline-soluble lead carrier. When (CH3CH2)4Pb burns, it produces not only carbon dioxide and water, but also lead:

(CH3CH2)4Pb + 13 O2 → 8 CO2 + 10 H2O + Pb
This lead further oxidizes to give lead(II) oxide:

2 Pb + O2 → 2 PbO
The Pb and PbO would quickly over-accumulate and destroy an engine. For this reason, the lead scavengers 1,2-dibromoethane and 1,2-dichloroethane are used in conjunction with TEL—these agents form volatile lead(II) bromide and lead(II) chloride, respectively, which are flushed from the engine and into the air.[/b:b373bf43f3]

Hardened valve seats, whether inserts (Stellite) or induction hardened seats, were recognized as necessary on high performance, high stress engines, and were a design point WAY before lead was removed from the gasoline.

Without all the chemisty, metalurgy, and observed physical behavior of engine valve components, the simple answer was provided very nicely and cleary by 504 in his post:

NO. :wink:

Tom,

Yes - I agree with you, originally lead was added to fuel to improve octane and not to prevent exhaust valve seat recession.

The objective of my post was to provide an example of testing and the resultant engine design change to accommodate non-leaded fuel. As such the original purpose of leaded fuel was not pertinent. I did not intend to imply disagreement by omission of this detail.

Sorry for any confusion I may have caused.

Ken

Ken, no need for apology. I actually like good healthy debate and discussion. Rarely are things in science as they initially seem. I deal daily with people who operate on conclusions drawn from observation vs. scientific fact. Now, I will be the first one to say that good observation is the foundation of good scientific principle. What is missing though, is the understanding of why.

I actually enjoyed your post.

(quoted from post at 14:53:31 11/02/11) The way I look at it lead was crap. They used to add it to low quality gas to make it perform better. Back when all we could get was leaded gas it seems like engines used to need frequent valve jobs. [b:c7e10aa078]My grandfather had a '59 Rambler that needed 3 valve jobs before 100,000 miles[/b:c7e10aa078]. When I was a kid we knew a guy that had an old Cat gas tractor, he would only run it on white gas.

My humble opinion is todays gas (except for the ethenol) is a much better product and better for your engine than the old leaded stuff.

Click to expand...

Now that's an accomplishment! Getting 100,000 miles from a Rambler. :shock: They definitely weren't known for their longevity. :lol: