James (et al),
I thought I'd address this to you, based on your confident treatment of the
subject, previously, but it's open to anybody.
I've been pondering the reduction in performance and rougher running since
my rebuild (2 years ago). The car ran great initially, but I screwed up on
the re-torquing of the head (at 500 km), blew the gasket a few months later,
and took it to a Triumph specialist (who's skill and workmanship I have
since had reason to question). It has run worse ever since.
Over Easter, I measured the valve clearances. Most of my inlets were .002"
to .003" under spec (I had all of them +/- .001" when I assembled the head
on the bench!). Do you think that's enough to take the edge of performance
and smoothness? (NB I'm running a 30/70 cam). And why did the clearances
reduce? (I am using leaded fuel, so valve-seat recession at a rate of >.001"
per year seems unlikely.)
I don't think I've exhausted the possibilities for tuning my Webers, but the
plugs appear to be burning fine.
BTW - this is a Dolomite Sprint engine. For those listers unfamiliar with
it, it is a 4-cyl, 2-litre (same block as TR7), 16-valve SOHC. The cam
drives the inlets directly, via cam buckets, but employs rocker arms for the
exhaust valves, so that each cam lobe actuates both an inlet and an exhaust
valve (which I think is pretty damn clever!)
Thanks in advance.
Allen Nugent
Graduate School of Biomedical Engineering
University of New South Wales
Sydney 2052 Australia
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