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: lead additive for older engines?


Everlandfarm
07-18-2008, 10:09 AM
Hi Folks,

Any opinions on using lead additives for the older engines which (presumably) were designed for leaded gas?

My only experience with it is with my 1954 Gravely LI, after spending some time on Gravely sites I decided to try some, ran a tank of gas with lead additive and one without when mowing. Didn't see any difference, but that may be due to the fact that you can't kill old Gravely's or that it was just lubricating and as such wouldn't be apparent to the casual observer.

I do know that with the old farm tractors which are all over the place around here, no one adds lead to the gas. e.g. A couple of years ago we sold a 1942 Farmall M which ran like a dream, we never put lead in the gas. Had to sell it, those tractors were unbelievable gas hogs!! Hmmm, to be perfectly honest I suddenly recall there are a couple of "tractor nuts" who restore the old machines for parades, etc. and they add lead but I don't know if that's to maintain their "purist" image or for some lubrication issue.

I'm curious as the 20+ year old Roper that I've got ready to roll except for a gas tank grommet which is due in "yesterday" would fall into the leaded gas category

SockPuppet
07-18-2008, 12:42 PM
I've used the additive but not in a tractor. I ran it in a '73 Grumman motorhome with a 440. I discovered that it shortened spark plug life drastically in that engine. Something in the stuff would coat the insulator and cause the plugs to short out. There was no way to get the plugs clean and I would have to replace them at a couple of thousand miles.

The last few years I had the MH, I ran straight premium and had no problems without the additive.

TOMMY
07-18-2008, 03:37 PM
When I Ran Into Carb Problems With My International,i Heard Different Stories And The Common One Was When They Made These
Old Tractors The Floats Were Set Using Lead Gas -a Little Denser
I Think Than Regulas Which In Turn The Floats In The Carb Have A Tendency To Settle In The Regular And Not Stay A Float.
So When The Machine Is Turned Off The Floats Sink In Reg
Still Pumping Gas Into The Carb And Overflowing
I Have Thought About Lead Add. But I Am Unsureof All Of This.

Everlandfarm
07-18-2008, 04:19 PM
When I Ran Into Carb Problems With My International,i Heard Different Stories And The Common One Was When They Made These
Old Tractors The Floats Were Set Using Lead Gas -a Little Denser
I Think Than Regulas Which In Turn The Floats In The Carb Have A Tendency To Settle In The Regular And Not Stay A Float.
So When The Machine Is Turned Off The Floats Sink In Reg
Still Pumping Gas Into The Carb And Overflowing
I Have Thought About Lead Add. But I Am Unsureof All Of This.

Hmmm, interesting thought. What I'd heard was that the lead was a lubricant for valves and things. Lead=graphite and I'm sure there are some of you who have lubricated locks by rubbing a pencil point on a key and inserting and turning the lock. Do that a few times and it does a good job. Lead is also a poison, check out the local walmart and it's toys painted with lead based paint as an example. Also, any hunters out there know that lead buckshot is a no-no, lead sinkers for fishing are still ok I think. I'm wondering if the lead we're discussing as a gas additive is actually a graphite for lubrication and not the lead the EPA, etc. is concerned about??

Anyone remember when the feds "forced" the gas companies to do away with lead in gas and then all we had was unleaded gas? As I recall from a newspaper article I read at the time, lead is an additive and as such it costs the refineries $$ to add it. Removing it would save $$ and eliminate a step in the refining process. Ignoring that, we got to pay more for "unleaded" gas which actually saved the refineries money to produce. This is the same "Big Oil" that is now going to save us by drilling in Alaska and offshore? And the feds are going to the same big oil that has us all ***** and bleeding over fuel costs and they're going to now "save" us??? George Carlin hasn't been gone that long, but I miss him!!!

If anyone knows more about the refining process for gas than I do, which has to be just about everyone out there please clarify as I'm confused. Also, "lead = graphite" mentioned previously probably isn't exactly true but it's something I've heard all my life.

Small Fry
07-18-2008, 05:29 PM
The lead was for the valve seats. With out the lead valve burning was the problem. Most if not all engines made in the last 30 years + or - have hardened valve seat inserts. No need for the lead in that case.

You can get away with out the lead in a old engine but you risk a burning a valve if it does not have hardened seats.

xPosTech
07-18-2008, 08:37 PM
Tetra-ethyl-lead was added to gas to increase the octane rating. An added benefit was some cooling of the flame front due to the increased octane rating, which helped to prevent valve burning.

Low lead (and now no lead) caused the refineries to reformulate the production of gas to get to the same (or actually slightly lower) octane rating without the additive, a carcinogen (tetra-ethyl). It is more expensive to produce a given octane rated gasoline without the additive.

Lead is a heavy metal element. It causes severe learning disabilities, especially children. Graphite is a form of carbon, also an element. They are not the same.

These are just my views and I'm probably wrong as usual, but I thought I'd throw my two cents in.

Ted

Edward
07-18-2008, 08:53 PM
The lead was for the valve seats. With out the lead valve burning was the problem. Most if not all engines made in the last 30 years + or - have hardened valve seat inserts. No need for the lead in that case.

You can get away with out the lead in a old engine but you risk a burning a valve if it does not have hardened seats.
the exhaust smell from leaded fuel vehicles was a pleasant smell to me; brought back memories! Weird, huh? I think unleaded exhaust stinks. Diesel stinks now, too as opposed to 30 some yrs ago...at least it seems to.

I used to buy a lead additive at NAPA when Florida did away with leaded fuel in the 80s but I cant recall the brand name

Small Fry
07-19-2008, 09:44 AM
Ted your right.

"In 1922, an American called Thomas Midgely (who also invented CFCs) found that if tetraethyl lead, Pb(CH2CH3)4, was put into petrol, particles of lead and lead oxide PbO are formed on combustion. This helps the petrol to burn more slowly and smoothly, preventing knocking and giving higher Octane ratings. 1,2-dibromoethane is also added to the petrol to remove the lead from the cylinder as PbBr2, which is a vapour and removed from the engine. (This is how lead is released into the environment from leaded fuels). Using higher-Octane leaded petrol meant that more powerful high-compression engines could be built."

http://www.chm.bris.ac.uk/motm/leadtet/leadj.htm

So is it the slow burning (of the leaded high octane gas) that saved the seats and not the lead it self ? And by using lead adtive your only slowing the burn ?

Thanks
Gary

Ed no more car exhaust for you....:biglaugh: Had to say it. :sorry1: