>Phil Smith wrote:
>
>>I'm not sure who, but someone made the comment that triumphs were meant
>>to be driven at the Red-Line. Is this just one person's opinion or are
> >their other listers out there, in agreement.
I guess from an engineering standpoint you could say that any engine
is designed to operate within the LIMIT of the red-line, but I think
it's a stretch to say they 'should' be driven AT the red-line. To
reinforce my point, by comparing other period engine designs it
becomes quite obvious that Triumph engines were not made with maximum
rpm in mind.
Compare a 240Z engine (L24) to a TR6 motor, for instance. Both six
cylinders, both very close to 2.5 liters. Set a TR6 crank next to
the Datsun L24 crank and you'll see that the L24 crank rides in SEVEN
main bearings, while the TR6 crank is only supported by FOUR main
bearings. This lack of support in the TR6 block & crank is an
inherent limitation in capacity for high rpms, as the TR6 crank will
be allowed to flex far more than an L24 crank. Also, of course the
L24's OHC design removes a fair chunk of reciprocating weight and
this allows higher rpm as well. The TR6's pushrod set up is just not
ideal for high-rpm work. And of course we're all aware of the TR6's
poor lubrication in the valve train. (on the other hand, NEITHER of
these engines benefits from a cross-flow head design)
My point here is only to say that Triumph motors in general do not
possess the design features that are generally necessary for high-rpm
running. It's not to say they CAN'T run at high-rpms providing that
modifications have been made to allow for it.
The other characteristic of Triumph motors in general is the
power/torque curve. These engines (in more-or-less stock form) do
not make their peak power at or near the red-line. In my TR6, for
instance, there seems to be no point whatsoever in revving it higher
than, say, 4000 rpm because beyond 4000 it's not making any more
power (or torque). I'm assuming that this is true to a large extent
with the other pushrod Triumph engines as well.
My contention is that most Triumph motors are happiest in the 2500 to
4000 rpm range. Exceptions are where owners have made special
modifications and provisions to build a 'hot' street motor, and of
course for the all-out racing engine. Racing engines, after all,
MUST be happy at maximum rpms. That's their JOB. But revving a
generally stock motor much higher than 4000 rpm frequently just
doesn't seem to be a useful endeavor
there's no power up there and,
I suspect, you're wearing out your poorly-oiled valve-train even
faster than normal.
--
Pete Chadwell
1973 TR6
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