[Fot] racing rod design

[Enquiries Road & Track]

i've been rebuilding race and street  engines for decades and have never
seen a conrod fail in the beam , that was not caused by another item
failing first.
In nearly every case its the rod bolt. Either it fails dramatically from a
defect, or it fails "progressively" , usually because the builder set the
stretch/torque wrongly.
In the latter case, its common to see the bearing commence spinning as the
cap slowly looses its crush on the bearing shells , the oil system cannot
hold up the pressure and typically the shell backing seizes onto the rod.
of course, all this can  happen in a matter of seconds
we have had apart modern 500-700hp turbo engines that have  cheap chinese
rods in them and they look like new provided they were installed correctly
In amateur racing, the discussions about rod shape are mostly academic. The
are truly valid pros and conds for all shapes of rods, but i would be
staggered if any that discussions was really a consequence in any triumph
engine as they simply are not at the cutting edge of engine technology
of far more importance are fundamental issues like, rod twist &
straightness (rarely an issue with new rods of any brand), big end tunnel
size and shape (notoriously bad on cheap rods) , oil level in service, BUT
most importantly, assembly practises

Terry  (engine shop owner)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/fot/attachments/20150724/f15eb5b6/attachment-0001.htm>