I believe this was from Dan Dasaro:
>
>I will provide an update when I can. For now, I have a brief update in
>that Bob has found that my carb is also responsible for my oil-fouling
>problem. A sort of vicious cycle occurred. We have the Castrol washing
>around, which seems to be a bad thing for a fresh engine, plus my front
>carb is out of whack, running rich, and sending gas down the unglazed
>cylinder walls. This thins out the oil even more and breakin never happens.
>
>I hope to have the car next weekend and plan on telling everybody how
>great it is to actually drive a well-running LBC. In the meantime, I'd
>recommend a 10W-40 Pennsylvania oil for your breakin. A friend here at
>work tells me the ash in PA crude helps a fresh engine.
>After 1000 miles or so (maybe more), once everything is seated
>satisfactorily, switch to the synthetic (I think you mentioned Mobil 1).
>
These issues (engine breakin and oil) are the subject of much heated
debate in the aviation community. Although aircraft engines are a
little different, being air cooled, I think many of the theories and
principles apply to water cooled automobile engines.
Engine breakin is considered CRITICAL to an aircraft engine's performance
and longevity. Air cooled engines have "looser" tolerances due to the
different coefficients of expansions of their aluminum and steel parts
and wide variation in local temperatures due to uneven, unregulated
heat generation and dissipation. Freshly rebuilt cylinders ("jugs")
have a wicked-looking coarse crosshatch hone. The first few minutes of
running a freshly rebuilt engine require proper care and technique in
order to prevent the formation of a baked oil glaze on the cylinder
walls, which will prevent proper breakin from ever taking place (the
engine will be an oil-burner thereafter). The engine is run for a
couple minutes, shut down, checked for leaks or problems, run a little
longer, shut down, checked. When available, the engine is run on a
test stand for the first few hours. The engines are always run at
full power or near full power, since maximum compression is required
to seat the rings properly.
Your friend is partially correct; new/rebuilt engines should be run
on straight mineral oil. Straight mineral oil does not contain the
dispersants used to suspend and carry away ash. I don't believe it
matters whether the oil is Pennsylvania or Texas grade (the former is
paraffin based, the latter is asphalt based), but it should not be
"Ashless Dispersant" (AD) type. Most mechanics recommend you use
a single-viscosity oil (30W), but some say multi-vis is OK if it's
not ashless-dispersant.
My father, who has been maintaining, rebuilding and restoring autos
for almost 50 years, and was once a high school auto shop teacher and
a factory rep. for Ford, says "people make too big a deal about (car)
engine breakin; drive `em as you normally would." Of course, he's a
fairly conservative driver. I'd recommend you avoid red-lining it
for the first few hundred miles, but otherwise just try to get a good
blend of city and highway driving, and avoid drag-racing any Hemi `Cudas!
Regards,
Bob
a
|