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July 23, 2005
Jim...what Colin said. :)
Do NOT use a low-friction oil in your (older)
rebuilt motor or the rings will more than
likely NOT "seat" as
the bores will more than likely "glaze" and
you'll have a "re-do" on your hands.
Use a normal 10W-40wt mineral based
"SF" oil for break-in. Change out filter
and oil within 100 miles (to remove initial
metal contamination) and again at 400 more miles for the same reason.
After initial 500 mile break-in (don't forget
to re-torque the head and re-adjust the
valves accordingly...then the carbs.)
The "new" factory motors are a different
story entirely in view of modern machining methods in the first place (basi
cally are
"pre-broken in") and are toleranced and mfg. with synthetics in mind in the
second place.
Synthetics get by on film strength alone.
Older engines are toleranced with non-synthetics in mind and thus thrive on
VISCOSITY ("thickness" for lack of a better word) along with film strength
.
Thus....AFTER initial 500 mile "break-in"...
...you might (as I now do)
use 3/4 mineral-based oil and 1/4 synthetic
for the best of both worlds with your (our)
"pre-historic" motors mfg. with "dinosaur" oils in mind.
BTW....
It is beneficial (cam wear) to set the idle
slightly higher than factory recommended
for the first 500 miles or so. Say 1,000 or so rather than 800rpm setting y
ou might use
after break-in with stock cam grinds.
Remember you are not only seating the
rings, but "burnishing in" (mating) metal
surfaces, the object being to remove the
least amount of metal from all surfaces
as they "work" against each other so as to
form (hopefully) a "compatible", long-lasting relationship.
So while you don't want to "baby" the motor (or the rings may not seat...th
ey need some heat/friction to do so, after
all) you don't want to rev it un-necessarily
either, thus "tearing off" metal rather than
"wearing down" the metal surface "peaks" slowly/gently (e.g. bearings, etc.
).
There...."I HAVE SPOKEN"!!! (Big deal, eh?:)
Cap'n Blob
Basic Frog
"Robert E. Shlafer" < PilotRob@... > 37965
Posted on July 23, 2005 12:20 PM
Posted to category(s) Carburetor | Cylinder Head | Engine (external) | Engine (internal) | Gauges | Intake System | Interior | Lubrication System | Miscellaneous | Restoration | Technical Info | Tuning
