Marvel Mystery Oil?

For real, MMO is transmission fluid.

I have used ATF, sometimes thinned 50-50 with mineral spirits or kerosene, as gun oil for over 40 years.

Also mix the stuff 1:4 ratio by liquid volume with beeswax to use as bullet lube.

Also use to mix with equal parts of K1 kerosene, acetone and mineral spirits to make my own rifle bore cleaner.

Brand doesn't matter as long as it's a known brand from one of the major US refineries, not the no-name recycled stuff from K-Mart or Walmart.

MMO is a good substitute for hydaulic fluid. It can be used anywhere 10-20 weight oil can.

...so, the benefit...

...of adding a little to our crankcase is to make the oil flow a little smoother?
...anything else? any additives that would break down the oil...or bluing??? Learning something here this morning, thank you....

If mixed with the proper weight engine oil in the crankcase,it will keep passages clear of "sludge" and keep hydraulic valve lifters operating properly. I've not used it on guns so I don't know of any adverse effect to bluing.

Thanks!!!

...I've used it " ...cause my daddy did..."

If mixed with the proper weight engine oil in the crankcase,it will keep passages clear of "sludge" and keep hydraulic valve lifters operating properly.

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Off topic but repeat after me.......OIL CHANGE..............this does more for your engine than any additive will.

It can; however MMO does have some mild solvent properties (similar to ATF) and may wreak havoc on very delicate finishes. If your guns are stainless though, by all means go hog-wild.

No argument from me about the oil change (even though most people change their oil TOO frequently). MMO won't do anything better than ATF

If it's anything like ATF it just has LOTS of detergent added. So yeah it should be fine.

I soak old, newly purchased, all steel handguns in Marvel Mystery Oil overnight, then I scrub their interior parts with a toothbrush. The MMO seems to help loosen any old gunk that's present.

I lube with ATF, and I clean bores and revolver cylinders with Ed's Red if the weather is warm enough to work outdoors (acetone). It's great stuff. Thanks, Ed!

{Edited to add: after scrubbing with the toothbrush and cleaning corners with toothpicks and such, I do rinse away all of the MMO with brake cleaner and let that evaporate before lubricating.}

Marvel Mystery Oil has been around for decades. Back when rod and ring jobs were between ten to twenty thousand miles we used it with the last oil change just before overhaul to clean up the engine. Of course, the “last” oil change was for a very short time. I never learned what was really in it but always suspected it was part kerosene with oil of wintergreen added to mask the smell.

I haven’t used it for many years because motor oil of today is cleaner, though some still has paraffin but I stay away from those brands. Also, engines no longer need an overhaul every couple of years.

I’ve heard it recommended as an additive to gasoline. I don’t do that because I haven’t seen a need and am certain it lowers the octane rating a bit.

I wouldn’t use it as a lubricant for guns, or for any other similar purpose, because it does contain a solvent of some kind, whatever that might be, and I want oil for lube, not a part solvent mix.

MMO won't do anything better than ATF

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Except smell better...
Joe

I use MMO mixed with Lucas oil and Mobil 1 - 1/3 of each for an all purpose gun lube for years with no observed damage and it works in cold weather well also.

If mixed with the proper weight engine oil in the crankcase,it will keep passages clear of "sludge" and keep hydraulic valve lifters operating properly.

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Mixing other types and grades of oil with SAE multi-grade oils commonly used in todays engines alters the properties of the oil. It can also void the warranty should an engine failure result. On older cars, MMO does act as a sludge remover when used judiciously to flush the engine.

Mixing MMO with engine oil will do no harm to an engine as long as it doesn't get greater than a 4-1 ratio and any engine that would need cleaning out would be long past any warranty. For guns:between MMO and ATF, I would choose ATF for the price.

Wishoot said:

I've been using this stuff in every engine I own for years. That includes cars, snowblowers, lawnmowers, inboards and outboards. I love the stuff in my engines.

I have so much MMO around, I was thinking it may be a decent product to use in place of my beloved Breakfree CLP to clean and lube my firearms. After all, MMO is used to clean and lube fuel injectors or carburetors. Economically speaking, I can get a quart of MMO for much less than a tiny bottle of CLP or almost any other gun cleaner/lube.

So is anyone out there using MMO on their firearms regularly?

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MMO is not a transmission fluid and it is a great cleaner for Nickle Guns or Guns with Nickle internal parts. It will not attack the copper undercoating needed for Nickle adhesion . I have been using it for 40 years now with no ill side affects.

jimmyraythomason said:

Mixing MMO with engine oil will do no harm to an engine as long as it doesn't get greater than a 4-1 ratio and any engine that would need cleaning out would be long past any warranty. For guns:between MMO and ATF, I would choose ATF for the price.

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The main ingredient in MMO is kerosene. I like the smell too.

I see no reason not to use it on guns. Let me clarify,I am not advocating using MMO in an engine as a matter of course but for clean-out only. MMO is used in some small truck manual transmissions and in hydraulic liftgate systems. It does not harm rubber o rings or seals. I would not recommend it in any automatic transmissions however.

I first ran into MMO when I was trying to revive a 21-liter Maybach aviation engine that had spent half-a-century in an old lumber loading dock. My neighbor, a retired aviation welder, suggested MMO for the valves, which were the only parts that were stuck. He said that MMO was originally designed for aircraft engine valves - either straight or mixed with castor oil - back when the valves were lubricated separately from the crankcase.

Well, it worked on this 1917-built engine, it also worked when freeing up the Mercedes truck transmission (chain-drive) that was attached to the engine, and it even worked on the friction-type shocks and other small parts on that old racing machine.

I've never used MMO on a gun, but I bet it would work!

MMO changes the viscosity index of a multi-grade oil. Will it ruin an engine at the 4-1 ratio suggested by jimmyray, probably not. Is it necessary in engines, no. Use on guns, I have no earthly idea.

Composition of Marvel Mystery Oil

I can't garantee that this is accurate.

Ingredient # 01
Ingredient Name BENZENE, 1,2-DICHLORO-
CAS Number 95501
Percent 0
Ingredient # 02
Ingredient Name MINERAL SPIRITS
CAS Number 8052413
Percent 0
Ingredient # 03
Ingredient Name NAPTHENIC HYDROCARBONS
CAS Number 64742525
Percent 0

(copied from a Jaguar website)

Well, I'll tell you: I put a little tranny fluid in my air compressor sump so it would run in cold weather. I probably added 20% tranny fluid:80% HD 30 weight. A couple days later the compressor wouldn't keep up with it's normal work and got hot. I had to rebuild the pump after that. I replaced the reed valves and graphite gaskets and it works good now. From now on I'll only put HD 30 in a pump and live with it until it runs enough to warm up when it's cold.