Hmmm ... this should be an interesting topic.
I haven't built enough engines to offer definitive advice, but it seems
the contemporary recommendation--for rebuilt older engines with flat
tappets, anyway--is to start the engine and run it at 1,500-2,000 rpm
for 15-20 minutes to bed in the cam (tune mixture, timing, etc. for rpms
and smoothness while it's running). The idea is to provide plentiful
oil flow to the cam and tappets during initial bedding-in. Would this
not apply to a Healey engine?
Some say 'break it in like you're going to drive it,' like my father who
has rebuilt numerous auto and other engines (corollary: 'break it in
slow, get a slow car'). He doesn't worry about the cam.
I know for aircraft (piston) engines break-in is critical--it's
universally recommended to run the engine at high power settings, full
rich at lower altitudes and no short hops for the first 50 hours or so.
To not do so is to almost guarantee that the rings won't seat.
I would recommend adding some sort of ZDDP additive to the oil--at the
least, it can't hurt and it may help protect the cam during break-in.
Before you start the engine, spin it over with the plugs out until you
get an oil pressure reading on the gauge (hopefully, you used copious
amounts of assembly lube). Also, it's recommended to run at varying
speeds and loads for at least the first few hundred miles so you don't
build a low ridge on the cylinder walls.
I don't think most new cars even state a breakin procedure--the
machining and clearances are so much more precise it isn't necessary.
bs
*******************************************************************
Bob Spidell San Jose, CA bspidell@comcast.net
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