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Excitement on Climb Out (rough running engine)
- Thread starter mfleming
- Start date
Absolutely no effect on octane according MMO's data. Might see an increase in your compression but no higher than 79/80 -- keeps my compression up there anyway.
Yes. Decalin is a chemical that helps to mix with lead bromide to help keep it in a gas state, so that it goes out with the exhaust instead of converting to a lead solid that can deposit. Mmo does something similar, but also has solvents that can provide a bit of lubricity and help to clear existing carbon deposits.
In my experience, a stuck valve always occurs due to build up in the valve guide and never from deposits on the valve stem. Due to the constant scrapping action, it is usually the bore and not the rod that collects deposits when the bore edges are exposed, such as the case with valve guides.A sticking valve is generally from crud that builds-up on the valve stem (either intake or exhaust valve). I'm guessing from your post that you have never experienced a suck valve? You're very lucky! I experienced a number of them before using a good fuel and oil additive (MMO and AvBlend). My first stuck valve was during PPL training on my long solo cross-country in 1978 and during my PPL check-ride. I've also had several in my Beechcraft before starting to use MMO and AvBlend, but none since then.
Just look at the standard fix for this. It is not cleaning the valve stem, but instead reaming out the guide to remove the build up that has collected and shrunk the bore diameter.
sansoneservices
Well Known Member
My EAA chapter has had many friendly arguments about MMO and snake oils in general. I agree with lr172 regarding the guide developing the carbon deposits causing the EX valve to stick. Chevron started introducing polyetheramine to their gasoline in the late 60's to eliminate sticky valves in flathead engines. They still sell it labeled as "Techron" but it's a FUEL additive
That's why I also use AvBlend during oil changes, and I don't use CamGuard or Phillips oil. Over the many years I've been flying (48-years) and also after owning several airplanes, where the RV-9A I built has been flying trouble-free (no sticky valves and runs smooth) for over 20-years and 1200 hours in a damp climate (Paine Field WA), I know what works for me! Since new (2004) other than engine break-in, I have always used simi-synthetic with Lycoming additive AeroShell 15W50 oil, AvBlendi in every oil change and 0.4 oz of MMO for every gallon of 100LL. I also change the oil every 25-hours and just before winter season. As a result, I have never had a stuck valve in my RV-9A. The engine starts and runs remarkably smooth every time, and my compression is still in the upper 70's and equal across all cylinders. I also found this same combination worked very well in my previous Beechcraft, which ran to TBO without any suck valves, and cylinder compression remained in the upper 70's. So, my combinations of "snake oil" works really well for me! However, you guys can use anything you like and continue reaming-out your valve guides! Frankly, it makes me wonder if this new combination of Phillips oil and CamGuard ("Group Think") might actually be causing your sickly valves.
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BTW -- "Group Think" is a psychological phenomenon where a group prioritizes harmony and agreement over critical analysis, leading to flawed decision-making. It occurs when members suppress dissenting opinions or fail to fully explore alternatives to maintain a sense of unity.
Could be. In the absence of scientific data, anecdotal evidence tends to fill the gap. A recent example was with the oil filter test - before this test we didn't know how badly the stainless steel reusable filters were at filtering oil compared to the paper elements. Conventional wisdom and the FAA said that they are about the same, but less costly, and easier to inspect. After getting the data, most went back to the tried and trued paper filters. I think if there was conclusive evidence that adding Snake Juice XYZ to our oil was beneficial, most of us would do it. I fully admit that I'm adding Camguard based on a few YT videos by people much smarter than I am, and I have very little data of any kind to back up that decision. If data comes along that shows that it's causing valve sticking, I'll stop using it.
This statement seems like a lot of MMO, “0.4 oz of MMO for every gallon of 100LL”. Did you mean .4 oz for every 10 gallons maybe?That's why I also use AvBlend during oil changes, and I don't use CamGuard or Phillips oil. Over the many years I've been flying (48-years) and also after owning several airplanes, where the RV-9A I built has been flying trouble-free (no sticky valves and runs smooth) for over 20-years and 1200 hours in a damp climate (Paine Field WA), I know what works for me! Since new (2004) other than engine break-in, I have always used simi-synthetic with Lycoming additive AeroShell 15W50 oil, AvBlendi in every oil change and 0.4 oz of MMO for every gallon of 100LL. I also change the oil every 25-hours and just before winter season. As a result, I have never had a stuck valve in my RV-9A. The engine starts and runs remarkably smooth every time, and my compression is still in the upper 70's and equal across all cylinders. I also found this same combination worked very well in my previous Beechcraft, which ran to TBO without any suck valves, and cylinder compression remained in the upper 70's. So, my combinations of "snake oil" works really well for me! However, you guys can use anything you like and continue reaming-out your valve guides! Frankly, it makes me wonder if this new combination of Phillips oil and CamGuard ("Group Think") might actually be causing your sickly valves.
.4 oz / gal is the correct dosage. If you want the benefits it provides, that is how much you need in the fuel. Not suggesting you need to believe in their product and not pushing it. From my research, it IS a good lead scavenger and why the military used it so extensively on the radials.
No -- read the MMO bottle for optimum MMO to fuel mix ratio! The bottle says 4 oz to every 10 gallons, so just do the math for every 1-gallon. Mix ratio is about the same as it would be for STA-BIL.
it sounds like detonation is possible depending on the concentration. This pilot claimed he was adding a quart of MMO when refueling (of 18 gal tank?) and turning the fuel from blue to pink.
does the color of the fuel change at all when using 0.4 oz per gal?
does the color of the fuel change at all when using 0.4 oz per gal?
According to that NTSB report:
"The contents of Marvel Mystery Oil were 74 percent mineral oil, 25 percent stoddard solvent, and 1 percent lard."
So mineral oil, paint thinner and lard are being added to the fuel?
Well, thats almost 2oz per gallon, so no wonder i guess. One case is not really fair to say it will cause detonation. Clearly he can’t read directions, so who knows what else he might have done to his engine to put him on the ragged edge of detonation before he used it.
I have not observed a color change when i use
