marvel mystery oil

Went out and bought some MMO. Dang, it does smell good.... Who'da thought? My wife said, "Must be a guy thing." Yup.
 
I use it in my gas tank with each fill but I've never quite had the courage to add it to the crankcase during an oil change. I see above 1 +3 and 1+4 with the filtered engine. So, MMO is as good as 30 wt or 10-30 / 10-40 oil ? Be interested to read some reasons why adding MMO to regular oil is a good thing or a bad thing. I'm sure this coin has 2 sides ! Thanks.
 
Pete, I really am nervous about adding ANYTHING to my oil except STP. STP has things in it that make it a stickier lube. MMO does not. However, If I'm going to change my oil on Friday, I might throw a few ounces of MMO into the crankcase on Monday. I read somewhere that MMO is basically a solvent, not a lubricant. That's why construction guys like it in Diesels. It helps to keep things clean.
Terry
 
A buddy of mine uses MMO in everything. He has a 87 H-D, and he puts it in his gas and oil.
Ok here's the deal...he's got 150,000 miles on the bike, and he had a base gasket leaking. He took it apart and the cylinders still had hone marks in em.' So we checked all the clearances,and they were all factory specs. NO WEAR!!!! I told him he should call "Ripleys" believe it or not.
 
MMO from my understanding, is a thin oil mixed with some detergents/solvents. While I've never used the stuff, the idea behind I feel is sound. With todays oils, I feel it's no longer as needed as it would have been in the times before multi-viscosity oils and high detergent oils, it can still serve a purpose.

MMO does thin the oil out, which would have been handy during cold winters. Thats probably what helped keep that V8 together that 40 Deluxe was talking about. A straight weight oil in those temperatures would have been brutal, but adding MMO do a 30 or 40 W oil would help bring it down a whole grade, which would have been great in those cold winters.

On an engine thats seen good maintenance through the years and runs a modern say 10-30, 15-40, etc would probably not always need anything else to keep it clean. But a few missed oil changes, or just a fluke causing some build in a lifter would make MMO great.

In my own modern stuff, I'll use Seafoam or Lucas fuel injector cleaner every oil change (about every 6-7k miles) and neither have had any injector issues since starting that practice. The 96 had an injector get plugged shortly after I got it, and I had the injectors professionally cleaned. Since then, no issues...she's got 220k miles now. The 07 has never had any injector issues. The Model A sees Seafoam probably a couple times a year, and a dose before winter hibernation. Since I've started that, the carb no longer fusses near as much after sitting.
 
Perhaps it was the Navy's requirement for strict adherence to preventive maintenance schedules with Milspec lubricants that got me hooked on "oils" or perhaps it was my first Model A, nevertheless I've read and reread this thread. My conclusion was that I "dont need it" because of a rebuilt engine in the ole boy. Next thing I know, I'm in an auto parts store buying MMO after a Club outing. Still saying "dont need it", in goes 4 oz. at a fillup and 1/3 quart was added next day after an oil change. What happened? A rough engine idle that this newbie could not adjust to save his life all of a sudden became perfect and the car runs smoother in 2nd gear. "Dont need it" turned to "use it".
 
I had carbon build up in a radial aero engine. the manufacturer advised to use Marvel Misery oil every 100 hours of operation. and yes it worked. On startup the next morning a substantial amount of carbon was exhausted. It was induced via the manifold pressure line whilst the engine was idling at 700 rpm.
 
socalplanedoc said:
I've encountered testimonials to the wonder cure that MMO creates in my years with hit-miss, antique car, and vintage plane groups. It wont hurt anything (other than a tiny hit on your wallet) but there's simply nothing more than anecdotal evidence that it has any direct benefit. Lots of guys swear by it and love to spin stories on how it fixed everything from stuck valves to scurvy - Just as many will tell you it's a waste of time. The reality is, if anything improved it's most likely from the increased attention the sick patient got.

BUT, if it makes you feel better to use it, well, feeling better is a good thing isnt it? :)
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I see you are from San Diego and restore vintage aeroplanes. I am aware of a vintage very near you that would create world attention if you were to restore and fly it. I would even come to the US to watch it's second ever flight. cheers, gary
 
I use it when I have the heads off to keep the cylinder walls oiled and clean - I use it heavily during this maintenance time and never had it foul up my motors. Great stuff.
You’ll be fine.
 
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