"Paul J. Adam" wrote:

:In message , Ricardo
writes
:Incidentally, a few sources have claimed that the Packard built Merlin,
:whilst a superb engine, lacked the power levels of the Rolls Royce
:version. This, it is claimed, was because the British kept secret the
:composition of the phosphor-bronze bearings that they used in the
:engine. No, I can't quote a source/s.
:
:On the other hand, I heard - from "old factory hands" lecturing on
:manufacturing technique at Highbury College in 1988 - that a big
:difference between Packard and Rolls-Royce was in fitting the cylinder
:head.
:
:Rolls-Royce used a precision hand-scraped metal-to-metal fit. Very
:effective, though extremely demanding in scarce skilled labour.
Attempting to 'file flat' is a useful exercise for a trainee mechanical
:engineer; it teaches a certain humility in demanding surface finishes)
:
:Packard cleaned up the castings, milled the mating faces approximately
:flat (at least, compared to a metal-metal seal) and put a gasket between
:them. I don't recall hearing tales of P-51s routinely or regularly
:falling from the skies when their engines failed, nor of the Packard
:Spitfires being execrated for unreliability (or, for that matter, lack
f horsepower).

Note that this is sort of the same approach that lost Germany the war.
Everything was hand-finished to very high standards, while us sloppy
folks cranked out ten times as many tanks as they could because we let
the tolerances be looser and eliminated a lot of the skilled
'touch-labor' in the finishing stages.

--
"Millions for defense, but not one cent for tribute."
-- Charles Pinckney