I enjoyed Tim Holbrook's recent submissions about oil and break in periods.
One of the things that we are overlooking, however, when we compare breaking
in any rebuilt engines with that of brand new engines is the difference in
the equipment, facilities and lubricants between our own meager garages and
the marvelous facilities of the car manufacturers. Many years ago I visited
a Ford plant and watched brand new Ford engines being tested on
sophisticated equipment which measured engine temperature, oil pressure,
engine speed, and probably many other vital signs. Before they were
started, lubricant under high pressure was circulated through all the oil
galleries so pre-oiling was very thorough. So, for most car companies, the
engines of brand new cars have had some running in even before the cars roll
off the assembly line. Also, many of the components for assembly line
engines are designed for minimum break in, and clearances and ring gaps are
often purposefully set to the upper end of the acceptable range to account
for the car buyer who jumps into his brand new car and takes it out on the
highway at 100 mph. On the other hand, parts such as piston rings that are
designed for the aftermarket, often are designed to deliver long life under
less than perfect conditions such as slightly tapered cylinders. Also, when
we set ring gaps and bearing clearances in the low to mid points of the
acceptable range, we have to be more careful about properly breaking the
engine in compared to the assembly line engine.
A few comments regarding the recent discussions about oil and synthetic
oil. New cars can be used anywhere from Arctic conditions to Death Valley,
so oil recommendations of the manufacturers have to take this into account.
The API and various manufacturers have conducted tests using very light oils
under extreme conditions and concluded that, usually, very light bodied oils
provide adequate lubrication even with heavy loading or extreme
temperatures. Hence, the movement toward using SAE5W-30 in new engines and
ATF (which is around SAE 10W) in manual transmissions and transaxles instead
of heavy gear oil. IMHO, almost any grade of motor oil meeting the latest
API specs would provide adequate lubrication for our prized Triumph engines.
The different grades might provide some different results in economy and
performance tests and cold starting ability, but none would probably lead to
engine failure due to inadequate lubrication.
Its finally summer in the Pacific Northwest. Palefaces are getting
sunburned!
Rex Townsend
Bainbridge Island, WA
1969 TR6 CC26713L
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