"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
of horsepower).

I think it's fair to say that Packard 'productionised' the design of the
Merlin which made it easier and quicker to build, possibly more reliable
too.

Graham