MMO in the Gas

[Model A Ron]

So who likes to add MMO to your gas? What are your pros and cons

[stickshift]

I'm a firm believer in MMO. It's been around a hundred years, so they must be doing something right. I also pour some in my crankcase about a week before I drain the oil and drive it around to remove any sludge buildup. I buy it by the gallon.

[Gary WA]

Been adding to gas for years! Good top end lubricator. 4 oz/10 gal

[J Franklin]

I use it to keep the valves from sticking, plus it smells great!

[ronn]

what J says- no cons other then having to pay for it!

[Model A Ron]

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Originally Posted by stickshift

I'm a firm believer in MMO. It's been around a hundred years, so they must be doing something right. I also pour some in my crankcase about a week before I drain the oil and drive it around to remove any sludge buildup. I buy it by the gallon.

How much do you add to the oil?

[Werner]

Good morning, Ron,

I have been using MMO regularly in my "Citroen Traction" in the gasoline tank for 8 years and 90,000 km. 50cc to 50 liters.

In my "A" for 3 years and 6000 miles with the vacuum dosing oiler 100cc per 100 miles.

The spark plugs, the piston crowns and combustion chambers apply only a few combustion residue and these are relatively soft.

[Big hammer]

4 oz per 10 gallons of gas for normal treatment, 8 oz per 10 gallons for sticking valve

[WHN]

Bought a Model A with a very noisy engine, very, very, very, noisy valve train.

100 miles later, using MMO and changing to High Detergent Oil 20w-50. Engine now sounded like it had just received a rebuild.

That was 40 years ago. Still quiet, still running great.

Enjoy.

[ronn]

quite the testimonial WHN!

[mcgarrett]

Added to gasoline, it leaves a light film of oil on the inside of the tank and helps fight against potential rust formation. Also helps neutralize the formation of rust in the float bowls of the cast iron Zenith carbs too. Considering the needs of older vehicles like ours I can't think of any real downside to using it, counting all the success stories like those listed above and especially with the lousy gasoline being sold today.

[mcgarrett]

Found this description of MMO on Wikipedia:

Marvel Mystery Oil is an automotive product of the American Marvel Oil Company,[1] founded by Burt Pierce in 1923.[2] It is used as a fuel additive, oil additive, corrosion inhibitor, penetrating oil, and transmission leak stopper and seal relubricator.

It is composed primarily of petroleum distillates, including mineral oil (60–100%), mineral spirits (10–30%), tricresyl phosphate (an antiwear and extreme pressure additive in lubricants, 0.1–1.0%), ortho-dichlorobenzene (a softening and removing agent for carbon-based contamination on metal surfaces, 0.1–1.0%), and para-dichlorobenzene (a precursor used in the production of chemically and thermally resistant polymers, <0.1%).

https://en.wikipedia.org/wiki/Marvel_Mystery_Oil

[jeepguy1948]

Mineral oil 60-100%? I wouldn’t want to pay for 100% mineral oil.

[Jim Brierley]

I do. I had a stuck valve on my old tractor, I'm sure it was caused by dry, modern gas. Tractors are a sob to work on, so I don't take chances on it happening again.

[stickshift]

A few weeks ago I submitted a post about a leak out of the rear of my oil pan. I took pictures of the trickle (not drip) on level ground after a drive. I figured I was going to pull the pan and that was also the consensus from other members. I put about 12 ounces of MMO in the crankcase and ran the engine thinking this would help get any junk down to the pan when I drain it. The next day the leak was a very slow drip (every 20 sec.) which I can live with. I decided not to pull the pan until I really need to, especially since I have other irons in the fire right now. The oil has remained in the middle of L and F. I'm not sure what the MMO did, maybe swell the gasket, or did something to the oil...but it stopped the trail of oil on my driveway. To answer MODEL A RON"S question about how much to put in the oil...they say on the bottle up to 20% of the recommended oil volume.

[BRENT in 10-uh-C]

Ok, for those who say it makes noises go away, or lubricates the top-end, coats fuel tanks, or that it can keep valves from sticking, ...please help me wrap my head around these thoughts.

We are talking 1 ounce of oil to 320 ounces of gasoline (4oz to 10 gallons of gasoline)! Think about that for a sec. Based on the dilution ratio of that oil, it seems to be a very minute amount to me. Next, the valve guide is not really in the path of where the air/fuel/oil travels, so does the valve stem really see any benefit? Especially in not causing a valve to stick in an L-head engine?? I would think not. So the final thing is, the upper-end of a Model-A engine is just the cylinder head. Not sure exactly what would benefit there from MM oil.

Again, maybe I am wrong in all of this but I struggle seeing a benefit.

[stickshift]

Originally Posted by Werner

Good morning, Ron,
In my "A" for 3 years and 6000 miles with the vacuum dosing oiler 100cc per 100 miles.

Werner, that is a nice automatic oiler setup. I checked on-line and I only saw old vintage ones for lots of $$$. There were some threads on HAMP about MMO oilers, but I didn't see one like yours. Is it vintage, or did you buy it and install it? This would take the time out of adding the MMO so frequently and answer the question "Did I remember to add the MMO to my tank"?

[Seth Swoboda]

Thats why I put a whole bottle in 10 gallons of gas. If a little is good, a whole lot is better.

Maybe MMO in the gas will help the intake valve?

I think adding it to the oil is where there could be some benefit to clearing up sticking valves. Like using Valve Medic.

[[email protected]]

I have always dosed my gasoline in the Model A gas tank in the hot summer months. It seems like doing some crawling slow July 4th parades the engine gets warmer than normal. The engine seems then harder to restart maybe because of "Vapor Lock". Seems like a little MMO helps prevent the gas from boiling in the sediment bowl all the way down to the carb bowl...

I also like the smell and put a couple of splashes on to attract the women....

[WHN]

Originally Posted by BRENT in 10-uh-C

Ok, for those who say it makes noises go away, or lubricates the top-end, coats fuel tanks, or that it can keep valves from sticking, ...please help me wrap my head around these thoughts.

We are talking 1 ounce of oil to 320 ounces of gasoline (4oz to 10 gallons of gasoline)! Think about that for a sec. Based on the dilution ratio of that oil, it seems to be a very minute amount to me. Next, the valve guide is not really in the path of where the air/fuel/oil travels, so does the valve stem really see any benefit? Especially in not causing a valve to stick in an L-head engine?? I would think not. So the final thing is, the upper-end of a Model-A engine is just the cylinder head. Not sure exactly what would benefit there from MM oil.

Again, maybe I am wrong in all of this but I struggle seeing a benefit.

Brent:

Maybe it’s like taking CBD. No one can really tell you how or why it helps, but for some people it does.

MMO seems to have worked for me. In one of my cars there was no other reason that the valves would have freed up and quieted down.

Enjoy.