Just testung new hard and software. Thanks for the indulgance.
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...... Original Message .......
On Sun, 05 Jun 2005 21:39:45 -0400 "James J." <m1garand@speakeasy.net>
wrote:
>I'm lucky to have an excellent machinist, who is a retired engine
>builder for a Busch series team, and now runs the engine lab for
>University of Maryland in the upstairs of his shop. He has wet and dry
>flow benches, ultrasonic gear and precision cam profiling gear, and most
>importantly, the incliniation to teach and share.
>A few nuggets he passed to me were:
>1) Mirror polishing the intake reduces turbulence, but allows for fuel
>puddling (even with EFI, but not so critical with direct shot heads,
>like the LS1 and LS6)
>2) Having a little step-up along the bottom of the port between the
>intake manifold and head also creates a little shear turbulence which
>helps keep fuel in suspension
>3) If your shop has modern precision valve and seat grinding equipment,
>never lap the valves, as the abrasive paste will never completely go
>away, and will ultimately destroy the seal. His gear can cut valves and
>seats surfaces to tighter tolerances than exists between the valve stem
>and valve guide, so valve wobble is the limiting factor.
>
>Even though I had him street-port my aluminum 300 heads, it would have
>been too expensive to take it to the max with ultrasonic thickness
>checking and flow-benching. Since there is almost no published data on
>the internal dimensions of the 300 heads (unlike Chevy and Ford heads)
>he had to be very concervative.
>
>My next step with him is deciding the optimal ram length for the Rover
>EFI pseudo-individual runners in a sports-car application (stock Rover
>length is for low-end SUV torque)
>
>JJJ
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