As a counter point, aircraft piston engines--which are admittedly
different with much
looser clearances--must be broken in at full or near full power, with an
extra rich
mixture. The extra gas is meant to wash oil OFF the cyl walls. If run
at lower power
and lean, oil can glaze the cyl walls and the cyl will have low
compression and/or
be an oil-burner for life. The first oil change is usually done at 25
or 50 hours,
which would be equivalent to 1,000 or 2,000 miles or so on a car.
I believe the "vary the speed" maxim is meant to prevent a ridge forming
if run at mostly
constant speeds.
If properly machined with modern equipment, a rebuilt Healey engine
shouldn't need
much of a breakin period. My Dad--former auto shop teacher and Ford factory
rep--says "break it in like you're going to drive it." I wouldn't baby
the engine, but
I wouldn't look for long uphill grades to run at WOT, either.
With a modern, full-flow filter I'd do the first oil change at 500
miles, the second
at 1,500 and whatever your routine is after that.
bs
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Bob Spidell San Jose, CA bspidell@comcast.net
'67 Austin-Healey 3000 '56 Austin-Healey 100M
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