Allen wrote:
James,
At 08:52 3/03/98 +0000, you wrote:
>
>Do you not mean running in. From what a friend tells me from >doing his
2.5Pi you need to break-in the engine, that is, use >almost no torque, and
leave off the top revs. 2/3 throttle >max. ...
I understood that you should red-line it a bit, under little or no load, to
establish the running limits. The conn rods stretch at the top of the
stroke, and the amount of stretch depends on their deceleration. Therefore,
if you avoid high revs during run-in, the ridge at the top of your
cylinders will extend too far down, and you will risk breaking a ring if
you red-line it sometime after it is run in. Any opinions to the contrary?
========================
My understanding has always been the same as Allen's; namely that during
run-in you should take it up to or at least close to red line. This is
common practice when rebuilding small block Chevy motors and it is what I
did when I rebuilt the Spit 1147 cc motor.
Ross D. Vincenti
64 Spitfire 4
64 Porsche 356C Coupe
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