run in oil

[helio lucas]

hey...
i want to run in a 4 stroke engine but i think i cannot do that with a normal oil... i´m correct right? what oil should i use? mineral most basic oil?
the run in is just new bore and new piston...
just want a opinion

 

[Jaybird]

Using any engine oil that is within the manufacturers recommendation of viscosity will be fine.
There is some controvercy about using a full "synthetic" oil for breakins, but it is my opinion that the concern is way overblown. More rumor spread by the Harley crowd than anything else...

And apparently some mfg's agree with me too, as they factory fill their bikes with "synthetic" engine oil.
Besides, the term "synthetic" is pretty much useless in the context of maintenance, as the term is really only valid in the context of marketing and advertisement.

Use any engine oil with the grade and service rating the mfg. recommends and you will be fine.
Always change all oil out often, especially one that is being used for breakins. You want to get the initial wear metals out of the engine as soon as possible.
I suggest dumping the first fill at about 1-2 hours run time.

 

[helio lucas]

ok
in eric gorr´s book and some other places of good information (not like almost every places in internet!!!!!!) they say that the oil cannot have some components like detergents and others things because they glaze the bore... and because the first time we run the engine, like you said, the run-in leaves very metal particles in the oil i was thinking in use a less expensive oil...
is this a bad practice?

 

[Ol'89r]

ok
i was thinking in use a less expensive oil...
is this a bad practice?

Helio.

No it is not a bad practice. Many piston/ring and cam manufactures recommend using a non-detergent oil for break-in. I use the inexpensive store brand of non-detergent for break-in and dump it like Jaybird says after 1 to 2 hours.

Of course, there are many that disagree with this.

 

[helio lucas]

ok i see...
each one makes their own way...
thanks i´ll fallow your advice...