Marvel mystery oil used as a lead substitute?

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mopar56

mopar56

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Ok, i know the subject of weather a lead substitute is required is a bit controversial So maybe there is two parts to this question, the first would be weather or not a lead substitute is actually needed on a early v8? The second is i have read that you can use a capful of marvel mystery oil to a tank of fuel to add the required lubrication. So here is the situation the motor in my 56 Dodge ( that I installed ) is literally a time piece , it was pulled from a 1970 Dart with 12000 original miles, ( the owner installed a 360 in it ) then the car was sold and the new owner didn't want the 318 which was a perfect donor for my 56. The engine is so clean it looks like it is new. I've had it for many years but as I posted on this site earlier this year I finally got my 56 on the road. The only thing I did to the motor was swap the car oil pan for a truck pan and swap the 2bbl manifold for a Eddy 4bbl one.The engine runs beautiful, no smoke , ticks etc. I primarily run Chevron 87 octane ( with Techroline additive ) sometimes I put some 94 in just because. So many say you MUST use a lead additive as my 1970 valve seats and guides will not be hardened others say it's a myth? I'm not sure I'll ever no for sure the answer to that. But I know there are lead additives you can purchase but some say a capful of the Marvel Mystery oil does the same thing? AND I have three large bottles of it. I don't put a lot of miles on this truck it's just a fun toy I drive a few times a month in the summer. What say you????
 
I wasn't aware that was one of it's attributes. It works very well for other things, but this is the first I've heard of this.
 
I have used MMO in several vehicles for years. I can't attest to benefits from tear downs but . . .
I had 79 258 6 in a CJ that was rebuilt stock but had balanced and ran a 1/2 quart in crankcase at 3000 mile oil changes and recommended mix in gas tank and that puppy ran like a Singer sewing machine. Naturally it was hardened valves, I'm thinking it couldn't hurt ?

It is more than a capful per tank, I don't recall but seems more like 3-4 Oz per 10 gallons.
 
I just did the googling and I haven't seen any website that says yes. I would be very leery adding any unknown stuff to an engine. Seafoam yep, states right on the bottle. My X heads don't have hardened valve seats, machinist said you'll never drive the car enuf to warrant them.
 
Used MMO for many years when I’d run higher compression motors. MMO is a lubricant so I can’t see why it would be a detriment to a motor. However Seafoam can dry out seals if used continuously. I’ve taken apart carbs where Seafoam was used. Seals pretty much dried out.on the accelerator pump on a Holley the umbrella seal would be totally eaten away. On
Y problem I found with MMO I would get a reddish stain on my rear bumper where the exhaust exited. So, I guess you have to pick the poison you are comfortable with.
 
The lead substitutes that are effective, legal, and somewhat available contain a chemical compound abbreviated as MMT. The middle "M" stands for manganese. Sort of like ZDDP in motor oil, it forms a sacrificial barrier on the valve and seat that prevents them from welding to each other and degrading the seat.

Amsoil's octane booster has this MMT. I use a bottle every other half-tank with 90 octane E-0.
Other brands have MMT, but not all.

I'm not going to discuss whether or not it's necessary. Do what makes you comfortable.
 
4spdragtop said:
I just did the googling and I haven't seen any website that says yes. I would be very leery adding any unknown stuff to an engine. Seafoam yep, states right on the bottle. My X heads don't have hardened valve seats, machinist said you'll never drive the car enuf to warrant them.
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Exactly.....but the fact is, you CAN drive the car as much as you want. What dictates hardened seats is exhaust temperature. Your car is so light, the exhaust will never be hot enough to warrant hardened seats. But you cannot tell people that no matter how much you preach it. Our light cars with good cooling systems and decent gears just don't generate enough exhaust heat to worry about.
 
RustyRatRod said:
Exactly.....but the fact is, you CAN drive the car as much as you want. What dictates hardened seats is exhaust temperature. Your car is so light, the exhaust will never be hot enough to warrant hardened seats. But you cannot tell people that no matter how much you preach it. Our light cars with good cooling systems and decent gears just don't generate enough exhaust heat to worry about.
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This is 100% correct.
I have driven thousands of miles on these old engines over the years and never had a problem with the valves being affected by the lack of lead in the gasoline.
Never.
My main concern nowadays would be the content of the ethanol in regular gas which could cause a lot of problems with the old rubber hoses, carb parts, and the fuel system in general by eating away at it.
That's why I use only mid grade or premium on my cars depending on the compression ratio.
It's better to be safe than sorry.
For a low compression 318, I would use mid grade and I have with good results.
On my 10:1/2 to one 340 I use Shell premium and have no issues such as pinging, running on when shut off, etc.
Chevron is great gas here in Canada, and so is Shell.
Regular gas has 10% or more ethanol in it and premium has a minimum of 0 to 5% up here.
I have always had good luck with Shell, but we don't get Chevron in the area where I live or else I would buy that brand.
The true test that I've found is how long does it take for the gas to evaporate out of the carb?
If it's a week or more, it's good gas.
If it's one or two days, you have a lousy brand of regular.
And as a side note, the places in Canada that have the good Shell gas is Shell (of course), Costco, and Canadian Tire.
Stay away from Esso, Fast Gas, or other low name places.
Petro Canada is okay, but not as good as Shell and Chevron.
I'm not sure of U.S. brands.
I hope this helps you...
 
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4 oz to 10 gallons for fuel. MM was developed for radial aircraft engines in WW2 era. Google it and you can find an article of the development, it's a good read.
I would run what you have and not worry about it. You may have induction hardened and not even know it. The auto industry knew unleaded fuel mandate was coming and didn't wait until 1973.
 
mderoy340 said:
4 oz to 10 gallons for fuel. MM was developed for radial aircraft engines in WW2 era. Google it and you can find an article of the development, it's a good read.
I would run what you have and not worry about it. You may have induction hardened and not even know it. The auto industry knew unleaded fuel mandate was coming and didn't wait until 1973.
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Hmm, on their website the reason they give for its development is different.

“Founded in 1923 by Burt Pierce, the brand has remained legendary for over 90 years. Pierce’s reputation for ingenuity preceded him as he was already well-known for inventing the Marvel Carburetor, standard equipment on 80% of all vehicles produced after World War I. Vehicles of the post WWI era encountered carburetor problems, the most perplexing being clogged jets due to high lead content and other contaminants found in the gasoline of the time. The problem motivated Pierce to direct his creative ingenuity towards formulating a blend of chemicals and petroleum products to clean and maintain clogged jets. He was successful beyond his wildest expectations and the legend of MMO was born.”

Sounds to me like it was developed to clear clogged carburetor jets due to high lead content.
 
TT5.9mag said:
Hmm, on their website the reason they give for its development is different.

“Founded in 1923 by Burt Pierce, the brand has remained legendary for over 90 years. Pierce’s reputation for ingenuity preceded him as he was already well-known for inventing the Marvel Carburetor, standard equipment on 80% of all vehicles produced after World War I. Vehicles of the post WWI era encountered carburetor problems, the most perplexing being clogged jets due to high lead content and other contaminants found in the gasoline of the time. The problem motivated Pierce to direct his creative ingenuity towards formulating a blend of chemicals and petroleum products to clean and maintain clogged jets. He was successful beyond his wildest expectations and the legend of MMO was born.”

Sounds to me like it was developed to clear clogged carburetor jets due to high lead content.
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My bad, I read about it 40+ years ago and my memory recall has gone to crap as the years go on.
 
I read somewhere that the airforce used mmo in the fuel of ww2 aircraft and it came in 45 gal barrel's for what reason i can't remember . Maybe for lead build up .
 
Well, as usual lots of good input, it seems several of you run these " old" unmodded engines without additives or issues and like i mentioned it dosnt get a lot of miles so I guess I'll just run it like have been on " good " gas. Thanks
 
In my humble opinion.....
Most guys don't drive their collector cars enough to need lead substitute. I might worry if I was driving 10-15,000 mi a year. Short of that I wouldn't bother.
But,if you have access, and really want lead..... a gallon or so of 100LL avgas would be plenty in a 20 gallon tank.
 
33IMP said:
In my humble opinion.....
Most guys don't drive their collector cars enough to need lead substitute. I might worry if I was driving 10-15,000 mi a year. Short of that I wouldn't bother.
But,if you have access, and really want lead..... a gallon or so of 100LL avgas would be plenty in a 20 gallon tank.
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10-15 thousand miles....lol, I'll be surprised if I put 1000 to 1500 on per year, I'm just gunna keep gassing up at the Chevron down the road with mid grade and not worry about it!
 
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