Brian Neuschwander wrote:
>
> Steve-
>
> I have the same problem on #4 and #6 rockers. I uses a wire gauge to
> set the gap, and also tried it a .008 instead of .010. Flat gauge give
> wrong setting on account of the cupping. The question comes up that if
> the tips are cupped, what abuse does this do to the valve stem and
> guide, since the force is a slightly different angle?
Well, I suppose it depends upon the degree of cupping (or pounding), but
the simple fact is that the rocker tip slides across the valve tip from
opening to closing, so it probably turns the valve a bit, if the valve
is capable of being turned. The largest problem is measurements of gap
for proper adjustment, as you say.
As I mentioned a few months earlier, I'd had rockers and shaft rebuilt
by a company known as Rocker Arm Specialist, then, recently. Some here
were a bit suspicious of the process since the rocker tips were reground
to a new profile (which makes adjustment infinitely easier); some had
alluded to their experiences at home doing the same thing, and suspected
that the grinding might have gone through the hardened layer. Some home
experiments in regrinding had done that, and the results were worn-out
rocker tips in a couple of thousand miles.
After several months of daily driving and half a dozen 400-mile round
trips, I can attest that the re-machined rockers are even quieter than
first installed, which I can only assume is related to gradual wear of
the small grooves from the initial regrinding, and nothing more.
They're still within initial adjustment, and the audible effect is
considerable. I do recommend this process and the shop doing it to
anyone with rocker difficulties. To recap, the shop mentioned above
cleans the shaft, grinds oil reliefs in the shaft where appropriate,
then hard-chromes the prepared shaft, beadblasts the rockers and the
pedestals, checks the pedestals for fit, reams and rebushes the rockers
with bronze bushings, and regrinds for the proper profile and rehardens
the rocker tips. Triumph six-cylinder rockers and shaft for $89 +
shipping. A damned good deal with good results. This is a very good
alternative to new parts, which I priced last year at more than $300
total, without the added advantages of hard-chromed shaft and bronze
bushes in the rockers.
Cheers.
--
My other Triumph runs, but....
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