Lead Additive

[JIPJOBXX]

I was wondering how many people use a lead additive in there old cars? I certainly do but how many other do also? Jon

[Young Ed]

No reason to in a mopar flathead. Quality engineering had hardened valve seats in these cars from the factory.

[BobT-47P15]

Right about the hardened seats. I have used a lead additive, but it's not really necessary. I used "instead o lead" made by Bardahl (i think)....but good ole wally world quit carrying it.

[TodFitch]

Like the man said: Hardened exhaust valve seats from the factory. I run the cheapest gas I can find and add nothing to it.

For more see:

http://www.ply33.com/Misc/gasoline

[Norm's Coupe]

As others have said, it's not needed in our flatheads. My coupe drinks straight from the tap.

[martybose]

I don't run an additive, but I do use 91 octane gas, because my mechanic recommended it, saying that flatheads tend to be prone to detonation at higher compression (Mine's about 9 to 1).

Marty

[norrism1]

If I remember correctly- Fluid Drive engines used Sodium filled valves. I don't know what the unleaded would do if anything. Just my thought on the subject!

[Norm's Coupe]

If I remember correctly- Fluid Drive engines used Sodium filled valves. I don't know what the unleaded would do if anything. Just my thought on the subject!

Actually, the unleaded gas doesn't affect the valves that much on any car. It only affects the valve seats on cars that don't have hardened valve seats. All of our flatheads came with hardened valve seats from the factory. That's why you don't need the lead additive.

[martybose]

Sodium-filled valves. Purchasers are warned that some valves that may be offered in the GSAAuctions.gov site may contain sodium that is explosive in nature when brought into contact with water. The purchaser agrees that he/she will properly dispose of said sodium valves at his/her own risk. The Government assumes no liability for damages to the property of the purchaser or for personal injuries, disabilities, or death to the purchaser or the purchaser's employee or to any other person arising from or incident to the purchaser of this material or its use of disposition. The purchaser shall hold the Government harmless from any and all claims of any nature arising from or out of the purchase use or resale of this material.

By definition, pure sodium is dangerous, but you have to ask yourself "What is the likelihood of the valve stem breaking, or of me getting the urge to cut into the valves or throw them in a fire?" I have never heard of anyone having any problems caused by sodium-cooled valves, which we have been using in engines for over 30 years. Note that the government statement doesn't say anything about properly using the valves, it just mentions properly disposing of them (presumably after use).

Personally, I'd be more concerned about the probability of blowing oneself up while working on an "empty" gas tank.

Marty

[Brad Lustig]

I've always wanted to get ahold of some pure sodium:D

I don't use the lead additive. I have a bottle on my shelf that I used until I found out about the hardened seats. I can use it in my Datsun, so it'll get used.

[Don Coatney]

One of the reasons the engines in these vintage cars are so full of crud is the lead used in the vintage gasoline. This lead designed to lubricate and cool the valves found its way into the oil and formed huge ammounts of sludge. Find a virgin (unmolested) engine fifty or more years old and you can bet the oil pan will be loaded with lead deposits.

[james curl]

I have been running un-leaded gas in my 55 Chevrolet 235 cu in straight six without hardened valve seats and stock valves ever since they removed leaded gas with no problems. The engine is going on 150,000 miles since I rebuilt it 28 years ago. It is modified with a HEI ignition, Fenton headers and a Clifford four barrel manifold with a Holley 390 cfm carburetor. The pick up has a 3.9:1 rear end that takes 3200 RPM at 70 MPH where I drive it on the highway.

[Robin (UK)]

I believe that lead wasn't added to gas until the early 50s, so all the P15s will run on unleaded gas without modification (just a slight timing adjustment).

There was a lot of debate in the UK regarding use of unleaded in classic cars.

Many people were of the opinion that valve seat recession was only significant after high mileage at high revs and, since most classics are used only occasionally, it's not really an issue.

Also, there was a suggestion that if the engine has previously been used with leaded gas for a significant amount of time, the lead would have thinly coated the valve seats and would offer protection for quite a while.

[Brad Lustig]

Looked up leaded gasoline on wikipedia

Back in the 30's, regular gas had an octane rating of only 40!

From Wikipedia - Leaded Gasoline

The mixture known as gasoline, when used in high compression internal combustion engines, has a tendency to ignite early (pre-ignition or detonation) causing a damaging "engine knocking" (also called "pinging" or "pinking") noise. Early research into this effect was led by A.H. Gibson and Harry Ricardo in England and Thomas Midgley and Thomas Boyd in the United States. The discovery that lead additives modified this behavior led to the widespread adoption of the practice in the 1920s and therefore more powerful higher compression engines. The most popular additive was tetra-ethyl lead. However, with the discovery of the environmental and health damage caused by the lead, and the incompatibility of lead with catalytic converters found on virtually all US automobiles since 1975, this practice began to wane in the 1980s. Most countries are phasing out leaded fuel; different additives have replaced the lead compounds. The most popular additives include aromatic hydrocarbons, ethers and alcohol (usually ethanol or methanol).

In the U.S., where lead was blended with gasoline (primarily to boost octane levels) since the early 1920s, standards to phase out leaded gasoline were first implemented in 1973. In 1995, leaded fuel accounted for only 0.6 % of total gasoline sales and less than 2,000 tons of lead per year. From January 1, 1996, the Clean Air Act banned the sale of leaded fuel for use in on-road vehicles. Possession and use of leaded gasoline in a regular on-road vehicle now carries a maximum $10,000 fine in the United States. However, fuel containing lead may continue to be sold for off-road uses, including aircraft, racing cars, farm equipment, and marine engines until 2008. The ban on leaded gasoline led to thousands of tons of lead not being released in the air by automobiles. Similar bans in other countries have resulted in lowering levels of lead in people's bloodstreams.[8] [9]

A side effect of the lead additives was protection of the valve seats from erosion. Many classic cars' engines have needed modification to use lead-free fuels since leaded fuels became unavailable. However, "Lead substitute" products are also produced and can sometimes be found at auto parts stores.

Gasoline, as delivered at the pump, also contains additives to reduce internal engine carbon buildups, improve combustion, and to allow easier starting in cold climates.

In some parts of South America, Asia and the Middle East, leaded gasoline is still in use. Leaded gasoline was phased out in sub-Saharan Africa with effect from 1 January, 2006. A growing number of countries have drawn up plans to ban leaded gasoline in the near future.

[vitamindart]

not only that its illegal to run leaded gas on the roads now , mind you nobodys going to pull you over and ticket you but they also wont sell it to you either , unless you buy leaded race gas , as for the lead additive its only octane booster or other additives

[knighthawk]

I was told that once lead is in engine(seats ), it's there forever, so , no need for and additive. except for the performance thing

[Don St Peter]

I have a 40 Ply with the stock flat head 6 and do not use additive and have been told countless time that it is not necessary since the valve seats are hardened.

Don