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There is no definitive answer. Sitting on the shelf, the points on a
pump can oxidize and the pump may not work 'off-the-shelf' without a
points cleaning (same for a car that sits too long). Note the
points' throw-over mechanism, set up properly, is designed to 'wipe'
the points with every cycle. Norman Nock said the pump would be
removed and the points cleaned as part of normal dealer maintenance,
at around 10K miles IIRC.<br>
<br>
At one time, at least, there were aftermarket points sold--maybe
before SU Burlen got back in the business--that came in a generic
white box and were made in one of the Chinas; quality was as
expected (i.e. non-existent). I had a set fail in a couple hundred
miles. I discussed this with the late Dave DuBois, who had a
post-retirement avocation of pump restorer, favoring various
electronic mechanisms, and he confirmed this theory. Those points
looked to me to be made of silver, instead of tungsten, which is a
dull gray color and, I think, may be more expensive than silver, and
the points were pitted after a few miles. Dave designed the
original, power transistor-based mod, but switched to a
photo-breaker mechanism later; results vary (ironically, perhaps,
the transistor-based mod didn't send enough current through the
points to clean them). Some have allegedly had points last for
decades and tens of thousands of miles, and some now swear by TVS
diodes (I didn't have much luck with them). Like any points set, the
points can stick to each other, which is sometimes remedied by
banging on the pump or its mount with a suitable blunt instrument
(fists, hammers, etc.).<br>
<br>
So, the answer is 'it depends.' I have had sets last several
years--15-20K miles--and I've had various failures at points between
with pretty much every alternative switching mechanism. As
aggravating as the SU pumps can be, I've found engine-driven pumps
to be even more pernicious, since filters and float bowls dry out
and must be refilled by cranking the engine if the car has sat too
long. In the case of my dad's '55 T-bird it's a crap shoot between
the engine starting and the 6V battery being complete drained; worst
case I have to resort to starter fluid.<br>
<br>
Bob<br>
<br>
<div class="moz-cite-prefix">On 5/25/2020 8:11 AM,
<a class="moz-txt-link-abbreviated" href="mailto:simon.lachlan@alexarevel.plus.com">simon.lachlan@alexarevel.plus.com</a> wrote:<br>
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<p class="MsoNormal">Basic question is: “How long, approx.,
should they last? (Yes, there is a diode thing across them.)<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">My car has been running OK. OKish…..I’d
swapped back from Webers to the three HD6s and had the car set
up at the rolling road place. They leaned the mixture settings
somewhat, saying it would run better and use less fuel. (A
relative term). I noticed that it took much longer to settle
down after starting. Quite a lot of rude noises and much play
on the choke at intersections. And, when it was up to
temperature, I wondered whether it was quite right…was it a
bit sluggish or was I just used to the Webers?<o:p></o:p></p>
<p class="MsoNormal">The other day, it hesitated and would have
cut out. But, with one bound I switched over pumps, and I was
free! However, the pump – double ended – had to come off for
inspection. Both sets of points were completely shot. I
replaced them. Nasty, fiddly business. Now the car starts much
better and performs better all round. Surprisingly so….<o:p></o:p></p>
<p class="MsoNormal">I installed that pump in 2012, +/-12,500
miles ago. So that’s +/- 6,250 miles per set of points.<o:p></o:p></p>
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<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l0 level1 lfo1">Would
failing points give those symptoms? (I was/am surprised….I
though points either delivered 100% or failed 100%. I know
that a judicious thump on the bulkhead can work in the short
term.)<o:p></o:p></li>
<li class="MsoListParagraph"
style="margin-left:0cm;mso-list:l0 level1 lfo1">How long
would you expect SU points to last?<o:p></o:p></li>
</ol>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
<p class="MsoNormal">Simon<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Glorious weather here and forecast all
week. Perfect Healey weather. One is allowed out, but not
really encouraged to go anywhere! Maddening. Pubs are
certainly shut. Anyhow, keep well.<o:p></o:p></p>
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