Marvel Mystery Oil fact or fiction

[Don Gale]

Back in the 40s and maybe earlier there was an Marvel Mystery oil injector. it screwed onto a mason jar with the oil in it, then a vacuum line to the intake manifold. you could regulate the oil flow with the injector.
Jay D.

Cool, probably most effective in flatheads and cast iron heads before hardened valve seat inserts came about, and especially for LP conversions lacking top end lubrication.

[Al Zim]

Guaranteed to foul spark plugs and cause billows of white smoke to follow you down the road. Fortunately stricter emission laws of the 1990's made doing this illegal. al zim

[Jay Darlington]

a friend of mine had one on a chevy 6 swore by it. all I know is the plugs stayed clean and no smoke. I believe I still have one i'll have to check the barn
Jay D.

[Martin Bruechle]

I used to buy it by the gallon and dump a quart in the tank for every 10 gallons in my VW.





That was when my buddy was getting the bottom of the barrel off the jet fuel tanker trucks from the LAX airport.
$1 a gallon for jet fuel for my VW Diesel. The jet fuel was very clean and needed some oil mixed in.

[Jon Schmid]

My dad used MMO in his Roadster back in the day. Maybe why the engine has only needed one full on overhaul (about 10 years ago) even with the then crap oil available back in the '60's.

[John Ward]

Don Gale, Amen ! on using it in flatheads.
I use it in my 41 ford pick-up with a 49 merc flathead V8. Runs perfect. but then again, I think that motor would run on corn squeezins.

[Don Gale]

edit: redundant duplicate post

[Don Gale]

[quote="John Ward" post_id=341981 time=1572044006
Don Gale, Amen ! on using it in flatheads.
I use it in my 41 ford pick-up with a 49 merc flathead V8. Runs perfect. but then again, I think that motor would run on corn squeezins.
[/quote]

As a starving student, I sold my 66 912 and I bought a 49 Ford pick-up. It should have had the flathead V8 but the previous owner literally welded a 394 Olds with a 4-spd Hydro into it. It was a novel ride but kept me jones'n for another sports car. A month later I bought the 58 356A coupe which I still have. I later acquired a 67 VW Beetle. I would run Castrol 20W50 GTX in the coupe for 1500 miles, drain and save it and run in my VW for another 3000 miles, save the drained VW oil and kept it in a jug in the back of the truck. When the lifters clattered, I knew it was 2 quarts low and topped it off from the jug and only changed the filter with cheap Kmart filters on sale. It thrived on abuse. I didn't care, it was a clapped out old work truck.

[James Watters]

Ran it for years in our Harleys especially in hot weather both in the gas and in the oil. I also run it in my 52 Ford F1 flathead.

[Matthew Devereux]

Ran it for a few hundred km in my Boxster to free up a stuck lifter after winter hibernation. It worked great.

[Wes Bender]

Quite a few years ago I bought a used M-B 300D Turbo. It had been in storage a few years. My diesel mechanic suggested I put a quart of MMO in the crankcase when I changed the fluids. The sticking rings were freed up in a little less than 1000 miles.

I still toss a shot glass of MMO in the fuel tank of the 356C when I gas up. Primarily as a top end lube. No smoke and that small amoount doesn't foul the plugs.

[Dave Whittick]

Guaranteed to foul spark plugs and cause billows of white smoke to follow you down the road.

100% disagree.

I’ve been running it in my flat tappet air cooled motors for 20 years. I add it to my fuel and crank case. I have 385,000 kms on the original motor in my bus. I also use it in a top end oiler on my Judson supercharged 36 hp.

It’s great stuff!!

[Ron LaDow]

I see a lot of 'well, I've been using it for years (and it hasn't harmed anything)', but not a bit of 'here's the problem it solved'.
Anybody got something on the later?

[Tom Wavrin]

MMO is equivalent to 5 weight SAE according to what I can find. I have an old bottle that I used to use in the tops of SU carbs. Use enough and it might reduce the viscosity, surface tension and oil pressure of the oil in the engine?
I do have a testimonial concerning Seafoam which is basically a mixture of petroleum based solvents. It wouldn't surprise me if the primary ingredient is kerosene/jet fuel, which also has lubricant properties. I use it in my wife's 2004 Vespa. The Spring after we purchased it new it would start but would stall after a short running period. This, even though I drained the ethanol-free gas for the winter. A colleague suggested I add Seafoam per bottle instructions to each tank fill. The stalling problem has not returned since.

[Phil Planck]

Jack Staggs recommends 3 oz. per fill up in the fuel tank if I recall correctly. He is not a Registry member, but possibly a member here who knows him can inquire as to his reason why and post it.