Success with Marvel Mystery Oil

[ngrimm]

Maybe the injectors like extra lubrication.

[pjbgravely]

One of MMO's benefits is removing carbon. I mainly use it on old small engine in the crank and fuel to prevent carbon build-up. That may be where your benefits come from. You probably can start using less with every tank unto you have a maintenance amount.

Other ways to remove carbon is too clean with steam or an Italian tune up (High RPM WOT driving).

[Olympiadis]

I recommend you not using it in your oil anymore due to the mineral spirits.
It is good for an engine flush, but not for continuous loading.

Solvents like mineral spirits will break down the oil film, and it doesn't take much.
It has the effect of thinning the oil. On high mile engines it also makes the blowby more volatile. Those two effects can/will increase fuel mileage, but it's not worth the expense of causing bearing or lifter/follower failure.

I couldn't say what concentration % of mineral spirits is enough to cause a failure, but I'm sure it's different for different engines and situations.
I have used mineral spirits on many occasions in several different ways.
You can put it in a sprayer and directly spray combustion chambers and pistons through the spark-plug hole. This will clean and often free-up piston rings that have either seized or have limited travel due to build-up.
Putting it in the engine oil is also a good way to clean the engine internally, but I only let the engine run at idle un-loaded, then change the oil.

I have added it to fuel on several vehicles as a cleaner for carburetors, TBI injectors, or MPFI injectors and fuel systems. It works well, but often has an effect similar to lowering of fuel octane, and that does improve mileage in many situations where the engine isn't heavily loaded.
I do not run it continuously in fuel so I don't have reliable mileage data.
In the vehicles that it improved the mileage in, Acetone has worked better, especially in cold conditions. For both additives the positive effect seems to be in proportion to how many miles are on the engine.
For example I could put some mineral spirits or Acetone in a brand new MPFI vehicle and get no significant measurable effect. On a vehicle with 200,000 miles the effects are very noticeable and easily measured.
I have test data for the Acetone, but like I said I haven't used mineral spirits or MMO on a continuous basis in order to collect mileage data. I buy the mineral spirits in the large metal containers from Lowes, and just use it as a cleaner.

*Mineral Spirits WILL dissolve lower grades of rubber over time. Acetone will do it even faster and has a wider range of materials that it will dissolve.

That is very interesting about the lean-burn mode and the sensitivity to the additive. Good discovery!

[darcane]

Anyone else try TC-W3 oil instead?
Been testing

I figured I'd give it a shot, but haven't used it long enough to notice anything.

[olds455]

I have used TCW3 in my '95 Chevy truck with noticable results (been too long for specific % or even mpg gains but I got 19.5 mpg on my commute with some ecomodder tips and who remembers what else). I followed a thread on Full Size Chevy forum that got me going. It has been quite some time since I ran it in the truck. I don't commute with it anymore. In the Century, I just added the TCW3 last fillup So, results have yet to be determined.

too new, cannot post the link. The thread is titled "2 cycle oil in your gas" and has a link to the LS1 forum. ^ "Been testing"

-Scott

[66sprint6]

I love Marvel Mystery Oil, it smells good, has tons of uses and is always found lurking somewhere in my garage. Havnt used it on the Escort, usually use it in my older, more wore out vehicles or to coat the cylinder walls on any motors I might have out and apart etc.
Matt

[roosterk0031]

Tried some MMO in Stratus, in 100k mile don't think I've ever put any kind of cleaner into the fuel(220k on car). Test is limited, but 2 tanks before MMO 36.2 & 36.9 mpg, next 2 tanks 32.6 & 34.9. Changed to E0 on this tank so should jump back up some. Next tank will be E0 and no MMO.

[WD40]

I got some $6.99 2stroke oil with TCW3 @ Canadian Tire and added the suggested 2 ounces per 10 gallons, and wow I noticed and immediate smoothness of my idle and throttle response was way smoother and way peppier.
Now to see if it helps in MPG.

[darcane]

I'm halfway through my second tank using TC-W3 (1oz/5gal). There appears to be a slight bump in mpg, but it's small enough to be lost in my typicial variation in mileage. The benefits are mostly cleaning and lubrication of fuel system components and top end of the motor, so I'll keep running it even if I see no recordable mpg gain.

[brucepick]

Marvel Mystery Oil (MMO) is somewhat heavier than gasoline, and gradually sinks to the bottom of the tank where it is picked up and consumed. So the concentration in your tank decreases over time or distance.

• MMO: 25.6 g/fl ounce (I weighed a quart on a scale with 2g resolution + did the math to allow for the weight of the bottle)
• Gas: 21.26 g/fl ounce (from wikipedia), see the "Density" section.

I've had nearly equal success whether adding 2 oz or 4 oz per 10 gallons gas. 2 oz/10 gal isn't quite as good as 4 so I suspect 3 oz/10 gal might be fine.

This all started when I found tthe availability of lean burn decreases after about 250 miles or 5 gallons (at ~50 mpg). I suspected the MMO is sinking to the bottom and being sucked up by the pump faster than the gasoline. The recirculating fuel system helps keep it mixed but there's nothing like splashing in a fillup to mix it all up.

At the 5 gal mark I'll be adding some MMO to keep the concentration up. Not sure exactly the dose and whether I'll add fuel at the same time or not.