What's "Break-In" Oil?

[RWEST]

I know this has been discussed before, but, for some reason, the Search function isn't helping very much.
Over in the J-D Owning/Operating section, they're discussing using J-D break-in oil, which got me to thinking 'just what IS break-in oil? How does it differ from regular oil?'

 

[AlanB]

The special "break in" oil that we used has a stronger add pack of some materials, I cannot remember exactly what all was in there, could run it down if you really need it, took me a while to find it at all as most people look at you rather quizically when you ask about it.

I will look around a bit and see if I can find the references too it. I do remember it was ridiculously expensive.

 

[3RRL]

Well, after all the vehicles I've bought over the years and now the tractor, I'm not too convinced a special "break in" oil is mandatory. I've read where most of the "break in" occurs within the first hour (or less) of running the engine at rated speed. You want to get any shavings and other metal particles out of there as soon as possible after that.

IMHO, I think using a good grade of oil and running your engine through a good work out to break it in will do the trick. Then change it and the filter out for your favorite brand of oil. Then stick to the manufacturer's suggested maintenance schedule.
But hey, it's JD so what can I say?

 

[AlanB]

Had a second so went looking,
It is Mil-L-21260 which has now gone over to the PRF specs, which would make it Mil-PRF-21260.

Anyway, googled about and found this site talking about it a bit.

Automotive Lubricants Reference Book - Google Book Search

Last time I bought it, I paid $1370.52 a drum vs. in the neighborhood of $200 a drum for standard 15/40 diesel oil. (Rotella, Ursa etc)

 

[ctjstr]

I guess the question is, what are you trying to accomplish with "break in" oil? Is it to help with the cleaning process on a newly rebuilt engine? Is it an effort to help seat rings? Pistons? Bearings?

From my experience, any decent oil will accomplish those tasks. I've found that if the engine is built to specs and clean, it will break in fine. If you miss the setup when building it, it doesn't matter what kind of oil you use, you're in trouble.

The one constant I have found is that heat cycling a new engine helps it live. Rings will normally seat almost immediately. Bearings essentially don't require seating. Where heat cycling seems to help is with pistons. With careful cycling, it seems to avoid some of the scuffing on piston skirts that can happen very quickly on a new engine. Does the type of oil used in break in make a difference? Not that I've ever seen. There used to be an old wives tale that you couldn't break in an engine on synthetic. That's pretty much hogwash, but you'll still find people swearing by it.

We can buy break in oil for the racing engines we build, but even the oil company hasn't been able to give me a good reason why, so I've never bothered.

 

[patrick_g]

There used to be an old wives tale that you couldn't break in an engine on synthetic. That's pretty much hogwash, but you'll still find people swearing by it.

We can buy break in oil for the racing engines we build, but even the oil company hasn't been able to give me a good reason why, so I've never bothered.

That old wives tale is a reworked version of an older one which had adherents using non-detergent oil for break in before switching to detergent oil.

There are a lot of ignorant people who are looking for some "magic" something they can do to make things better. They are easy prey for all sorts of chemical elixirs, nearly anything mixed with petroleum distillates, put in a container with lots of BS ad copy about the wonderful benefits of the product and stocked on the shelf at the FLAPS or Wally World. The purveyors of these faith healing miracle cures capitalize on the ignorance of the buyer.

Please don't inundate me with anecdotal stories about how a couple cans of Motor Miracle in a Can did such and such. There are a few products out there with benefits in some instances that outweigh the cost. The hard part is knowing what to use for what and when to use it at all or if it is reasonable to expect a benefit.

Most of us are unknowledgeable as to what to use, when to use it, and such. Many just cast their fate to the wind, buy something and try it blindly (even use in accordance with the instructions is still mostly blind use as there is little or no science or engineering behind the claims.)

When I was in grade school and Jr High (back when the big rocks were still hot) you ran non detergent oil for break in or your rings wouldn't seat properly and your oil consumption would be high forever. With non detergent oil the BAD stuff would settle out if you put your old oil in a large container and you could reuse it. (The forgoing is JUNK don't do it.)

Pat

 

[IH3444]

The only thing I do for a new engine is use a light weight oil, such as a 0w-20, for "break in". This almost always insures if there is a tight place between a new piston ring, and a ring groove, then it will get lubercation due to the lighter oil being able to flow into the minimum space. This is all I did on my performance porsche 911 engine. Ran for 40 minutes to allow the new cams to "break in". Dumped those quarts, and refilled with good quality 10w-30 for the next "break in period". Then to mobil 1.