Chris wrote,
>For years, my Alpine was my only mode of transportation. At times, my work
>commute was long (35 miles one way). For anyone familiar with Atlanta
traffic,
>you know that driving fast is the only way to avoid being hit. I would
average
>4500 rpms to and from work. Occasionally, I would drive at 5000 rpms for
20-30
>minutes at a time just for the fun of it. My Alpine is very comfortable at
>4500. I get a little nervous at 5000. The engine is professionally
balanced,
>but with no tricks. Everything is stock. It is a Series III so I guess it
has
>the 3.89.
Wow!
I wouldnt have a problem running at a continuous 4000 RPM, any reasonably
maintained alpine engine shoulnt mind that too much, but the earlier engine
running (3 main) running for 20-30 minutes at 5000 RPM?
Thats definately pushing the edge of the envelope.
Factory engines are not well balanced.
Two years ago I got a hold of two cranks and 2 sets of con rods for 1725
engines.
The con rods were cleaned and weighed, and found to be ±15 grams of one
another.
Pistons were also all over the place.
Even the wrist pins had significant mass differences.
Only one of the cranks made its way to the balance shop, which it came back
with
a pretty fair set of new holes in the counterweights.
Of course weighing all these was only an excersize becuase only the crank
was used.
The rods were swapped out for carillos, and pistons alla J&E, all of which
were
dead nuts weight matched.
I'd say if anyone else out there wants to run continuous 5000 RPM on a pine
motor,
make sure its professionally balanced like Chris's.
Jarrid Gross
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