Mineral Oil Myth

[Webb]

This should start a lively discussion. I've got another thread going on engine break in but ran into this article.

Let the fun begin.

http://www.avtoday.com/am/categories...nance/564.html

[mahlon_r]

It may be a myth but it does work. If you are the guy that has to warranty the situation, if the engine doesn't break in correctly, you tend to go with advice that you know works. So, if the engine manufacturer or overhauler wants you to use mineral oil, you should do it, because he is the one that has the finical liability of fixing the problem, if the engine doesn't break in correctly. In my opinion, you should do it his way and expect the results he says you will get. If you don't get those results, the onus is on him to rectify the problem. Or, you could do it a different way, then the manufacturer or over hauler recommends, and get results that you don't like, but then you will be on your own to rectify the problem. If it does break in OK, without following his requirements, then you didn't loose anything but if it doesn't, it would be unfair to expect the manufacturer or overhauler to warranty the situation because you didn't follow their requirements.
For certified aircraft, it would actually be a violation to not use mineral oil, as the Manufacturer recommends. Just because it seems like a good idea isn?t justification to do it. We are required by law to follow the Manufacturer's Instructions for Continued Airworthiness and if they say use minreal oil then we have to do it.
Still recommending mineral oil, where applicable, and having no break in issues.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

[BigSky]

Originally Posted by Webb

This should start a lively discussion. I've got another thread going on engine break in but ran into this article.

Let the fun begin.

http://www.avtoday.com/am/categories...nance/564.html

We had this situation come up a couple of months ago. I only skimmed the article but it looked like it was saying that there is no reason why you shouldn't use regular oil for breakin (at least scientifically). My theory is why not use mineral oil. Its not that big of a deal. Plus, if I heard correctly, not using mineral oil could have an affect on your warranty (at least in the certified engine world). I say do what the manufacturer says its not a big deal to change the oil at 25 hours or however long it takes for a breakin on a particular engine.

Are there any upsides to using regular AD oil?

[OKAV8r]

... at least that is what two different presentations at Sun N Fun said. Phillips X-C is an AD oil, but it does not have an "anti-wear package" in the formulation. In contrast, every other AD oil commonly available has some type of EP/ anti-wear formula. That is why Phillips X-C was singled out by Lycoming for the requirement to add LW16702 additive.
This fact makes X-C a very good choice for break in.
I DO NOT work for Phillips, by the way.
But, I have used X-C for break in twice now, with good results.
BTW, the article was written 2003? I think Lycoming has changed it's stance since then...

[BigSky]

One more thing, I looked up the price and it looks like AD is more expensive that Mineral.

[Don Jones]

Originally Posted by OKAV8r

... at least that is what two different presentations at Sun N Fun said. Phillips X-C is an AD oil, but it does not have an "anti-wear package" in the formulation. In contrast, every other AD oil commonly available has some type of EP/ anti-wear formula. That is why Phillips X-C was singled out by Lycoming for the requirement to add LW16702 additive.
This fact makes X-C a very good choice for break in.
I DO NOT work for Phillips, by the way.
But, I have used X-C for break in twice now, with good results.
BTW, the article was written 2003? I think Lycoming has changed it's stance since then...

I too have used Phillips X/C for the initial fill on a newly overhauled engine. It was and still is recommended by ECI for break-in on all their engines and cylinders. Mine sealed up really quick and won't even use a quart between oil changes. I for one don't buy into the "straight mineral oil" myth.

[osxuser]

Aeroshell 100W doesn't have the antiwear package either (100+ does).

Like many things in aviation, the good theory is lost on people who don't understand what is really going on. The result is an explanation that lacks scientific backing, and therefore is disproved eventually. Mineral oil is no less "Slippery" than AD oil, we all know that is just absurd (or at least we should).

The real basis for using NON-AD oil in engines for break-in has to do with exactly what they are talking about in the article, particle suspension. The AD suspends particles in the oil, which in turn can start to fill in some of the grooves in the cylinder walls (especially with the high metal content in the first few hours) and result in glazing the cylinder wall.

With NON-AD oil, the particles will settle out after the engine run, and won't stay suspended.

All above information is simply my understanding, not trying to agree or disagree with above article.

But why not? What do you have to lose by running cheaper mineral oil for the first 50hours?

[SHIPCHIEF]

Doesn't mineral oil need to be changed at 25 hours instead of 50 hours like AD?
Mineral oil does not have an additive package, which extends the useful life of the oil.
I don't see any other engines (car truck ship or rail) that require mineral oil for break in.
On the other hand, the break in oil should not stay in the engine very long, (in a hard working engine with only a few quarts capacity) particularly if you only have an oil screen (no filter). Run that new engine a bit, then dump that oil to get the 'grinding paste' out, and put in some new oil. The break in oil should not be in the engine long enough to need a life extending additive.
I don't think it's important enough to argue about one way or the other.

[Mike S]

OSXUSER hit it pretty much on the head.

I had a long conversation with the guys at the Shell oil booth at OSH about the detergent/non detergent thing.

To make a long story short, non detergent, AKA "Mineral" oil lets the particulate matter fall out to the bottom of the pan. It stays there until you open the engine, and scrape it out--the oil pump pick up was usually mounted quite above the bottom of the pan, just for this reason.

This was desired in the days before engine makers used oil filters.

With the use of oil filters, the particulate matter needs to be suspended in the oil, so it can be removed, thus the advance of detergent oils.

The goal of either method was to keep the crud out of the lubrication, where it will cause damage.

[erich weaver]

Call me anal, but....

Being a newbie a few years back when I bought my engine, I was confused by the terminology used in discussing this subject - specifically the terms "mineral oil" and "detergents". My research has indicated that these terms are thrown around quite loosely, and apparently often incorrectly. My understanding is that, in correct useage, "mineral oil" means only that it is petroleum based - i.e. produced from an oil well, as opposed to synthetic oils, which generally are not used in our RV engines (the Rotax 912 is an exception - blends of petroleum based and sythetic based oils [semi-synthetics] are recommended for those engines).

So, we are all using mineral oil. I believe what is being discussed here is, more correctly, only whether or not our (mineral) oils should include an ashless dispersant (AD) additive during break-in. As noted above, Lycoming and TCM say no. ECI says yes.

"Detergents" are not used in modern oils. This term is often incorrectly used to refer to oils with AD additives.

It would be helpful to the younguns to be clear and use the correct terminology here; granted, the vocabulary is a bit entrenched at this point.

best regards
erich