Listers,
Aa couple of weeks or so Jonmac inquired about spring cap replacements and I
recommended Performance Research Industries (www.prirace.com) in Oregon. A
complete set of 12 forged alloy caps is $125 and are the same for both
intake and exhaust.
I could not find any reference to factory single cap for the exhaust in any
of several TR catalogs, hardcopy or on-line. It seems that the double cap
on the exhaust has always been there. Maybe the change was in the later
Triumph Vitesse sedan. The reason why they are double caps I cannot say but
it is definitely a bigger pain to remove them versus the single caps!
Insofar as the 'uprated' valve springs for a hotter cam I also have been
told by knowledgeable sources that the best thing to do is buy the set of
valve springs that are matched to the cam, if at all possible. Higher seat
pressures do not guarantee anything in a street motor except faster wearing
valvetrain components. In many cases the stock springs are more than
capable in working with moderately higher lift cam profiles. However,
adding a much higher rocker ratio such as 1.75 changes the equation as the
springs are then compressed closer to the point of coil bind. It's the same
as if a much higher lift cam were used. All of this translates to more
stress and wear. As one source stated, "Sure, the part is used in highly
stressed race motors. But then race motors are regularly rebuilt and worn
parts replaced." I do not think that any of us want to regularly rebuild
our motors, even once every few years!
And I highly recommend to always use hardened lifters. Compared to refaced
or standard $6 lifters, IMHO the cost difference does not justify either
alternative in light of the expensive consequences of taking such a route.
Greg Dito
CD6250L
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