What's your experience?

[Mike M]

Marvel Mystery Oil + avgas = ?????

a. solution for sticky valves
b. trouble
c. neither problem nor solution
d. other

[CarlOrton]

a

[rwanttaja]

Eons ago, I had a crusty old A&P who had gotten his start working on Constellation and DC-6es. He told me to use Marvel Mystery Oil to prevent my valves from sticking.

Haven't had a sticky valve in 30+ years of C-85 operation. So mark me with an "A" as well.

Also works great as an elephant repellent. Since I started using it, I haven't had a single elephant in my hangar.

"B" can be valid, if you use too much of it. ISTR an NTSB report where the plane's oil tank was half MMO.....

Ron Wanttaja

[1600vw]

I was told years or decades ago aviators purchased this stuff in 55 gallon drums. There must have been a reason they used this. It's a shame this reason died with these aviators. Why we need to share all we know so we can pass this down to the next generation and not make them learn all this over again.

Tony

[vaflier]

I know a crop duster who uses it in his big old radial engine daily and has for many years. He and his mechnanic swear by it. His engines usually run a long time with few problems. Never a stuck valve. He has been at it for over 30 years.

[sr2500]

At one point, Steve Bennett, formerly Great Plains Aircraft Engines, told me to use 25 % Marvel Mystery Oil with my 30 W oil in the VW.
Jerry Folkerts

[L16 Pilot]

Used at times in the fuel small amount. I forget the exact ratio (4 oz / 10 gallons?) but it's hard to figure when the tanks are either not empty or full. I don't doubt the effects are probably beneficial especially when using 100 LL in low compression engines as it probably helps scavenge some of the excess lead. My understanding is because of the light viscosity it tends to 'flash off' in the oil so it's rather short lived. To my knowledge I've never had a sticky valve in near 40 years of flying although I never used the stuff on a regular basis.

[CarlOrton]

As a follow up to my "A" response above, and to L16's comment about how much. I used it in an old O-300 in a 172H. I don't remember the ratio (it's been 10 years since I've had it...), but I just added the correct ratio after refueling. I knew how much 100LL I put in, and added the "correct" amount of MMO. Also used TCP for the lead scavenging.

[Joda]

I had a valve stick on an O-320 many years ago, and my mechanic said to put some Marvel in the gas and run it for a while before doing anything else. It worked! Freed up the valve and no problems after that. I've used it in all my airplanes ever since. (It also helps lubricate the Piper fuel selector valve in the Super Cub.) I use the 4 oz in 10 gallon formula, but sometimes I'm not all that precise.

[martymayes]

This is obviously an example of b:

https://www.ntsb.gov/_layouts/ntsb.aviation/brief2.aspx?ev_id=20020916X01610&ntsbno=NYC02LA181&akey=1

and it's fitting as it seems to be a mystery how it got in the fuel....

[Mike M]

LARD kind of takes some of the mystery out of it?

[dothetime]

I have been putting MMO in my fuel for 26 years, five aircraft. I never experienced a stuck valve.
Coincidence?
Dave
N601XP

[choppergirl]

I wonder how many of you, walking on the shady side of town, would buy a Marvel Mystery Burrito from a vagrant in a grungy Spider Man t-shirt that came up and offered it to you.

But Choppergirl, it's all about location, location, location. Walmart is way more trustworthy.

That being said, I've put it in gas tanks before with no ill effects; unsure if there were any quantifiable positive effects either.

[stewartb]

For sticking valves you add MMO to the engine oil. In the gas it helps to prevent lead fouling and deposits. I've added it to avgas off and on for 25 years because I was taught to.

[martymayes]

I have been putting MMO in my fuel for 26 years, five aircraft. I never experienced a stuck valve.

If we are going to use faulty logic, we could conclude from your experience that the valves didn't stick despite the use of MMO, not because of it.

Somewhat amusing that despite an engine manufacturer publishing a document expressing prohibiting use of a product is not satisfactory to overturn folklore.

[stewartb]

His logic makes more sense than your baseless dismissal.

MMO is light base stock oil with Varsol added. Simplified a little but that's the basic recipe. Got a too-tight valve guide? Thin oil and solvent may be beneficial. History says it has been in big radials. In fuel? It helps with lead problems. That's a more recent problem with 100LL being the only aviation fuel most of us use. If you don't want to run it? Don't, but that doesn't mean the rest of us are foolish for using it.

[martymayes]

MMO is light base stock oil with Varsol added. Simplified a little but that's the basic recipe.

More precisely: 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard (aka pig fat)

Caveat emptor my friend

[robert l]

What could be better than firing up your engine and the smell of bacon comes out !!!!
Bob

[DaleB]

Oh, you need some of this... https://m.summitracing.com/parts/plu-19769-45

[Tom Downey]

Who remembers the mis fueling that happened in California? 4 major airports had less than 5% diesel contamination?

the engines torn down by Lycoming and TCM all had signs of detonation present..

what is the major ingredient in MMO?

[Mike M]

Who remembers the mis fueling that happened in California? 4 major airports had less than 5% diesel contamination?

the engines torn down by Lycoming and TCM all had signs of detonation present..

what is the major ingredient in MMO?

I'm kind of slow. At the MMO-recommended 4oz per 10gal, does that make the engine digest 3.125% or .3125% ? Because that might be significant or no big deal. Depending. But it's still LARD?

[1600vw]

More precisely: 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard (aka pig fat)

Caveat emptor my friend

Have you ever used break in oil? It's castol oil. Says it right on the bottle. Castol oil nothing more then plant oil.

[Marc Zeitlin]

More precisely: 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard (aka pig fat)

Caveat emptor my friendI'm with you that there is no objective statistically significant evidence that MMO does anything for either stuck valves or for that matter, lead scavenging, although it DOES have a tiny bit of TCP in it, which is used for lead scavenging. Multiple anecdotes do not equal data - I've NEVER used MMO in my engine over a 15 year period and have never had a stuck valve - what does that prove? But there's no evidence that it does any harm, either, unless you really don't like the smell (which I don't).

With respect to the question of "lard", the MSDS for MMO:

http://www.audiosears.com/MSDS/FS0433-Marvel%20-%20Marvel%20Mystery%20Oil.pdf

indicates five total components, none of which are animal derivatives. There's no lard in MMO, according to the folks that make it.

[Marc Zeitlin]

I'm kind of slow. At the MMO-recommended 4oz per 10gal, does that make the engine digest 3.125% or .3125% ? Because that might be significant or no big deal. Depending. But it's still LARD?4/1280 = 0.003125, or 0.3125%. Other than sell some MMO, I can't imagine that it has any effect whatsoever, but YMMV.

And no - see my post above - no lard, according to the MFG. Some weird OWT, apparently.

[martymayes]

But there's no evidence that it does any harm, either, unless you really don't like the smell (which I don't).

With respect to the question of "lard", the MSDS for MMO:

http://www.audiosears.com/MSDS/FS0433-Marvel%20-%20Marvel%20Mystery%20Oil.pdf

indicates five total components, none of which are animal derivatives. There's no lard in MMO, according to the folks that make it.

The NTSB investigation indicates it can cause damage to an engine and an engine manufacturer seems to be convinced well- to the point they will void a manufacturer warranty.


WRT the composition, I am not making any claims. Only reporting what the NTSB found

[Tom Downey]

I'm kind of slow. At the MMO-recommended 4oz per 10gal, does that make the engine digest 3.125% or .3125% ? Because that might be significant or no big deal. Depending. But it's still LARD?
Question,, Does adding any amount of oil to your fuel raise the BTU content of that fuel?

[martymayes]

I'm sure we all appreciate your smart ass comments. In case you didn't read the question, the poster was looking for experience using the product. I gave my experience.
He did not ask for opinions. Opinions are like ass holes. We all have them.

I'm sorry. I thought you asked a question as well.

[Mike M]

Question,, Does adding any amount of oil to your fuel raise the BTU content of that fuel?

If oil has more BTU per volume, I'm guessing "yes"