Newly overhauled "0" time 0300

Alan · Post by **Alan** » Mon Sep 01, 2003 3:16 am

I just had my engine overhauled and new Millenium cylinders, new mags,overhauled stater generator etc. etc. I have about ten hours on it now. Like you folks in the US, I can't get 80/87 anymore and I detest 100LL. Previously I have been using about 25% 100LL and 75% regular mogas mixed. I am getting lots of advice on what to do and what not to do with this "new" engine etc. So far I have used only 100LL.

I would like to go back to my 25/75 mixture but some folks say don't ever do that. Others say it shouldn't matter. Does anybody from the association have information on the subject ? If so, I would love to hear from you.

Oh yes, at the risk of opening up this Marvel Mystery Oil subject, I plan to use some of the oil as well. How much per gallon or liter exactly should I add. I read someplace one of the things it does, is to keep the temperature in the combustion chambers a bit lower. Is this fact or fiction, and also just what else does this "mystery" stuff do ? Whoever named that oil "Mystery Oil" sure had the proper name. It is one heck of a mystery to find out

exactly what it does.

Bye for now,
Alan in Montreal

#6481.

JDH · Post by **JDH** » Mon Sep 01, 2003 4:36 pm

Alan, new paint, new interior, fresh engine... You're ready for the $100 hamburgers now!
When I broke my engine in, I spoke with Guy-Paul Mongrain who had rebuilt it. He recommended mineral oil till it seated properly, with oil change at the first 10 hours, then 25, then 50 (I flew the first 50 hours in 2 months), then switch to Aeroshell 100W in summer and 15W50 in winter. He recommended I stick to 80-87 or 100LL for the first 50 hours before going to Mogas. I've done all that and the engine now has aprox. 300 hours and the compression is right up there, temperatures are normal, all is well. I use Mogas 90% of the time. I put Mystery oil; 6oz per side every 2nd or third fill up. Never had problems with vapor lock, carb ice, etc and Sally goes out all year, all weather. ST3 now has mixed gas. JD

Dave Clark · Post by **Dave Clark** » Wed Sep 03, 2003 12:36 pm

Alan

I agree with JDfor the most part except:

1. I would change oil every 25 hours, and if you have a spin on filter then change that every other oil change. Especially don't use 15/50 longer than 25 hours because it will break down and not thicken as well as it should giving you less than 50 wt and more leaks and consumption.

2. I used to use a lot of mogas but would not do so now (plus I can't with the Lycoming). I think the fuel has changed, it burns dirty and dirty inside the engine as well, and you can never know the "mix" or additives in what you are using which bothers me no small amount. I know for sure it eats o-rings where the mogas we used years ago did not. If you do use it I used to mix it 50/50 which brings the lead content down to about that of the old 80/87 when it was leaded.

3. There is a lot of info on MMO here just do a search. I don't think it would really do any harm in modest amounts in the fuel but a properly run and maintained engine shouldn't need it. Unless you're burning mogas.

Flame suit on.

Post by **GAHorn** » Wed Sep 03, 2003 5:57 pm

IF you are a proponent of mogas in airplanes,....there is no reason to mix avgas with it. All the avgas does is add the nasty lead to your mogas. (There is absolutely no truth to the popluar idea that lead is necessary for "valve lubrication" or anything else except to increase the octane level of the stuff.) The original engines have no detonation problems with 80 octane fuel and they do not need either the lead OR the unnecessary extra octane rating of 100LL.
If you are concerned about fuel quality, shelf-life, questionable additives, and uncertain/changeable recipies and the damage it causes to aircraft fuel systems and components, then mogas added to avgas simply pollutes the avgas. IMHO (OK Eric?)

Tom Downey · Post by **Tom Downey** » Wed Sep 03, 2003 6:29 pm

I definitely agree with George on this one.
Mo Gas is not a cure all, it just has a defferent set of problems.

Alan · Post by **Alan** » Wed Sep 03, 2003 6:43 pm

JDH wrote:Alan, new paint, new interior, fresh engine... You're ready for the $100 hamburgers now!

J.D.:

No money left for hamburgers !!

When I broke my engine in, I spoke with Guy-Paul Mongrain who had rebuilt it. He recommended mineral oil till it seated properly, with oil change at the first 10 hours, then 25, then 50 (I flew the first 50 hours in 2 months), then switch to Aeroshell 100W in summer and 15W50 in winter. He recommended I stick to 80-87 or 100LL for the first 50 hours before going to Mogas. I've done all that and the engine now has aprox. 300 hours and the compression is right up there, temperatures are normal, all is well. I use Mogas 90% of the time. I put Mystery oil; 6oz per side every 2nd or third fill up. Never had problems with vapor lock, carb ice, etc and Sally goes out all year, all weather. ST3 now has mixed gas. JD

Thanks for your thoughts. I have about twenty hours now and mineral oil is
wht I'm using. The aircraft is in P.E.I. just now and I'm going to get it next week. Plan an oil change when I get back. I'll try to come out and see you again before the month's end. I'm going to Dayton later this month but back before the end. Will come up one day and talk with you.

Alan

N3243A · Post by **N3243A** » Thu Sep 04, 2003 10:27 pm

gahorn wrote:IF you are a proponent of mogas in airplanes,....there is no reason to mix avgas with it. All the avgas does is add the nasty lead to your mogas. (There is absolutely no truth to the popluar idea that lead is necessary for "valve lubrication" or anything else except to increase the octane level of the stuff.) The original engines have no detonation problems with 80 octane fuel and they do not need either the lead OR the unnecessary extra octane rating of 100LL.
If you are concerned about fuel quality, shelf-life, questionable additives, and uncertain/changeable recipies and the damage it causes to aircraft fuel systems and components, then mogas added to avgas simply pollutes the avgas. IMHO (OK Eric?)

Come on George, "pollute" your avgas with mogas and "no reason to mix avgas and mogas"? You draw such hard lines in the sand and use inflammatory words that you really must wish for responses. That's OK, we have been around on this enough that I almost expect it.

Adding mogas to you avgas no more pollutes it than your inflammatory posts pollute this forum!

How about mixing the two fuels to achieve the best properties of each rather than seeing the mixing as "polluting" either (depending on your point of view). I respectfully submit the following:

Avgas pros:
1. Uniform quality
2. Higher octane rating (due to lead)
3. More resistant to carb icing

Avags Cons:
1. High Price
2. Too High of Lead content

Mogas pros:
1. Lower Price
2. No lead

Mogas Cons:
1. Quality a little more variable and must be careful to avoid oxygenated gas.
2. 87 octane mogas (RON+MON/2) has a Motor Octane Number (MON) of 82. Only 2 points above our minimum of 80.
3. Slightly higher tendancy to carb ice

Therefore, mixing gives you a fuel that is cheaper than 100LL, has about the same lead as the old 80 octane avgas(depending on your mix ratio), and resists carb icing a little better than straight mogas. Personally, I will use either fuel straight or mixed depending on the circumstances and availability. As long as they are both clean, fresh and oxy free my airplane has never known the difference. I will confess that my preferred fuel is a 50-50 mix of each so let the flames fly!!!

As for our C-145/O-300 engines not needing any lead for lubrication/cushioning effects, how about those of us with engines that were overhauled in the 1970's (or earlier). Might we have valves and seats that aren't as hard as more modern cylinders and benefit from a little lead? I really don't know the score on this aspect, but have been operating under the assumption that a little lead is good for those of us in this older engine component category.

No desire to reignite the Mogas wars, Bruce (really I don't)

Post by **GAHorn** » Thu Sep 04, 2003 10:42 pm

OK, then,...how about not polluting your mogas with avgas? Same thing. If one of them is your preference because of the CONs of the other, then why include any of the other? There's no need for lead in any of our engines, no matter when they were last overhauled. The so-called "100-octane" valves, seats, and guides were to deal with scavenging the excess lead in the 100LL to get it out of the engine. So why would you deliberately want to add an abrasive, pollutant you don't need like lead to the fuel?
What inflammatory posts? I'll delete them.

N3243A · Post by **N3243A** » Thu Sep 04, 2003 11:35 pm

Why would I include Avags in my mogas? I thought my post was clear enough.

Tetraethyl lead is abrasive? First I have heard of this.

What inflammatory words? Using the word "pollutant" to describe one fuel as added to the other is over the top and inflammatory in my opinion. Both fuels work just fine alone or mixed. Whatever... Just be sure to follow the usual caveats using either. Why must you insist that one or the other is a "pollutant" depending on your point of view?

To Alan and other new guys reading this type of post, they might consider mixing of fuels to be bad or "taboo" because you referred to one as a "pollutant" to the other. You are entitled to your opinion and own operating procedures but that is not the only way to view things. I voice this as one who disagrees with your position so as to give a varied response to the query at the top of this thread.

Respectfully, Bruce Christie, N3243A

zero.one.victor · Post by **zero.one.victor** » Fri Sep 05, 2003 4:01 am

Right on,Bruce,I agree with you on both the fuel issues & the "inflamatory" issue,also.

Eric

JDH · Post by **JDH** » Fri Sep 05, 2003 1:38 pm

Dear Bruce, Eric, Dave, Alan, George and all... I will try to clarify my earlier post without letting any of the worms out of the can...
Dave, I do change my oil, oil and air filters every 25 hours. The first little bit, to break in is where I changed the oil and oil filter at 10, then 25, then again at 50 hrs; at which time the consumption had stabilized and I went to 15W50, which I did not like in the summer, so, the following oil change, went to W100 until fall and regular 0ÂºC or close to it overnite, then back to 15W50 till the white stuff was off the ground.
Bruce, Eric and George, we all have opinions about the Mogas, MMO (with or without the dance) issues, some of us with more "detonation" than others and yes, it is sometimes tough to "feel" the tone of a response or opinion; lets remember to stay friends and avoid "carb icing".
George, I agree with Eric and Dave on using Mogas; it works for me and you have to get informed as much as you can on the subject and do whatever is good for you, including safe refueling method, where you are based, availability of Avgas or good Mogas, convenience, etc; its not always about being cheaper.
In expressing our opinions, we (and when I say we, I don't mean me...) have to try and do it in a way, especially when looked upon as an authority or very experienced one, that doesn't sound like "we" have the "only" truth or gospel and that everyone else's opinion is dumbfounded or wrong...
Peterson and EAA have all kinds of writing on the subject to help one make up their own mind about Mogas.
By the way, to add a little fuel to the post: I heard yesterday that Shell came out with W100 Plus, which contains a certain amount of AVBLEND... Made me laugh, cause I remember reading something last couple of years about some Dr. Egghead at Shell saying Avblend had no benifit...
JD

Post by **GAHorn** » Fri Sep 05, 2003 8:35 pm

Thanks, JDH for the words.
Just to make it clear, once and for all,... to all...I do not take issue with an owner who chooses to use mogas in his airplane. No matter how sensitive some of them might be about avgas-only users discussing it,...I don't have a problem with them or their practice. It's their plane, and the octane in the auto fuel certainly is sufficient.
It seemed to me that the major differences that avgas vs mogas users have is the views of a purist crowd vs a frugal crowd. If avgas is the only stuff for airplanes in your opinion, then mogas is a pollutant. If in your opinion mogas is all your plane needs, then adding a fluid with lead in it only pollutes it. It was my intent to indicate that mixing the two has absolutely no benefit to either fuel and only makes mogas more expensive and harmful to your engine, (presumably defeating the reason you wanted to use mogas in the first place), but if you're the type that believes avgas is all that should be in an airplane, then mogas simply destroys the integrity of the aviation fuel. Again, I don't take issue at all with mogas users. I may have in a past life, but I've come to realize an owner is the final authority with regard to his own property.
That was my point, Bruce and Eric. The only reason lead is in gasoline (aviation or otherwise) is to boost octane. Since that's the only reason, and since lead is harmful to both the environment and the engine, (in the engine: it is an abrasive, in that it forms little glass-like globules that erode parts, it fouls plugs, if fills their cavities with junk, it precipitates into the oil sytem where it sticks valves and makes grey sludge (also abrasive), ...in the environment: it contributes to lowered I.Q. in children, it limits executive judgement (that's the type wherin one is unable to determine the consequences of one's actions), and it is documented to contribute to aggressive behavior. ( Hmmmmn

) In either case, avgas added to mogas contaminates it with lead, and mogas added to avgas contaminates it with chemicals avgas is prohibited to contain. (Avgas may only contain carbon and hydrogen atoms, no oxygen, alcohol, or other substances than tetraethyl lead are allowed.) In Webster's pollute:contaminate are synonyms.
I recommend everyone take a chill pill and quit letting the hair on our necks stand up whenever we see mogas, lead, avgas, or MMO in msg posts.

zero.one.victor · Post by **zero.one.victor** » Sat Sep 06, 2003 4:03 am

A parable,if you will,about mixing cargas & avgas:

A man was served a straight shot of rum,and he sputtered. Served a straight shot of coke,& he spit. Served a tall glass of rum & coke-- he cried out "this is it!"

Moral: sometimes a combination is greater than the sum of the parts.

PS: Read the Petersen cargas STC with regards to their opinion about mixing 100LL & unleaded cargas.

Eric

Post by **GAHorn** » Sat Sep 06, 2003 5:03 pm

Eric, why don't you cut/paste Petersen's advice. I assume it is merely "advice" and not a required action of their STC? If my assumption is correct (I know, I know, Ass ume) then only theirs is foolish and/or misguided. If their procedure is actually part/parcel and req'd of the STC, then it only proves how widespread the mis-belief is, ...that lead is beneficial in any fashion whatsoever other than as an octane-booster. (My airplane is "modified" for the EAA AutoGas STC, and it contains absolutely no requirement OR advice to mix avgas with mogas, and also makes no claim that lead is beneficial in any way.)
Ideally, in my opinion, they'd let us flip the "add lead" switch at the pump, then those of us who don't want it could with-hold it from being delivered into our tanks, and the cost savings could be re-directed for the consumer who doesn't need/desire it. Maybe we should start writing letters to our politicians.

N3243A · Post by **N3243A** » Sun Sep 07, 2003 5:13 am

gahorn wrote: I recommend everyone take a chill pill and quit letting the hair on our necks stand up whenever we see mogas, lead, avgas, or MMO in msg posts.

Actually, I did take a chill pill on this topic. Instead of firing right off the first time I read the "pollute" post I waited a full day before deciding IF I should reply and then HOW to tactfully approach the topic because I knew we would wind up in a pissing match.

My response is purely a rebuttal and different viewpoint on the subject.

One last item. As JDH put it so well, using mogas is not all about frugality. It's about convenience and availability as well. If you fly Alaska and the Canadian Arctic enough (especially off the beaten path), there are times when mogas is your only choice. If you are comfortable using mogas, the experience won't be so traumatic and in fact will be anticlimactic!

Nuff said, Bruce