I should point out that on A series engines, constant high revs will
ususally result in a cracked crank (and then loss of oil pressure)
well before rod failure. The rods on A-series engines are *very* strong
and the cranks are a bit suspect.
Wedging the crank will help the cracking susceptability. Rolled radius cranks
were used on some later A-series engines which helped a lot (though according
to Vizard, the early batch of these cracks had a flawed rolling process).
Tuftriding or nitriding the crank is the best way to eliminate this problem.
A-series engines cranks that have been cross-drilled, wedged, and nitrided
or tuftrided will happily run at 8,000 plus for a couple of seasons' racing.
Of course, you should also have better (dual) valve springs and better
rod bolts if you plan to do this!
Mike
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Mike Gigante
3D interactive graphics, Virtual Reality, british sports cars, and wine
http://mega.cgl.rmit.edu.au/~mg/ mg@mega.cgl.rmit.edu.au
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