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<p>It is not uncommon that a car´s service sheet also included the
SU-pump (clean the points every service), e.g. Lotus Eclat/Elite.
However I never did and I have had no problems. I used my car as a
daily driver but it had to live outside all year. Nowadays the car
is pampered in a heated garage and is mainly driven when the
weather is suitable for open top driving except for long trips
abroad.<br>
</p>
<p>The pressure delivered by an SU-pump depends on where the pump is
situated. If it is fitted under the bonnet it should be a so
called low-pressure or suction pump delivering 1,8psi (e.g. some
Austin-Healey Sprite/Mg Midget). You can often recognise this pump
by the 2BA screw (same size as the screws that hold the coil
housing to the pump body) on the coil housing for the earth spade.
If the pump is fitted near the petrol tank it should be a
so-called pressure pump delivering 2,7psi (e.g. MGB) or 3,8psi
(Austin-Healey 3000, Jaguar 6-cyl. cars MkII, E-type etc., Triumph
Stag, Jensen-Healey a.o.). The high pressure pumps can be
recognised by a smaller 4BA screw for the earth spade. The
pressure is fixed and is controlled by the spring fitted under the
diaphragm. All pumps are identical as far as the coil housing,
points system, diaphragm are concerned. The differences are in the
pump body but this has no effect on the pressure, mainly on the
variation of delivery pressure and flow rate. Some cars have the
h.p. pump fitted on the chassis open to the elements (e.g. MGB,
A-H), others have it protected in the boot (e.g. J-H).<br>
</p>
<p>There are three types of spring, the low pressure 1,8psi spring
can be easily recognised as the wire is rather thin and it has
more coils, the 2,7 an3,8psi springs have less coils and look
identical to each other but the 3,8psi spring is slightly thicker
and should have a (faint) dab of red paint.</p>
<p>If the SU-pumps would have been so unreliable as some of you
claim, they would not have been used on such a large scale. Many
millions of cars have had them in the 1930´s through to the
1990´s, from the humble Morris Minor to Rolls Royce.</p>
<p>Sure, the early ones did wear the points rather quickly because
of arcing/spark erosion, but this was counteracted by proper
maintenance which was usually every 1000 to 3000miles in the 30´s
up to the 50´s. The wear was significantly reduced by using a
simple capacitor (very like the capacitor in the points
distributor), then a diode and lately Burlen fitting a transil.
The pumps are dual polarity except when a diode is fitted. <br>
</p>
<p>However spark erosion is not the main problem, that is
electrolytic corrosion due to lack of use and dampish conditions
under the cover because of improper ventilation like no tubes
connected from the pump to a dry area of the car (boot) or no
rubber band or friction tape on the joint of the cover and coil
housing or damp storage.</p>
<p>I am not sure if the quality of the points you buy today is less
than the old ones. I have never used them. I still have NOS points
to replace worn points, but more often than once cleaning and
repolishing the old points will do.</p>
<p><br>
</p>
<p>Kees Oudesluijs<br>
</p>
<blockquote type="cite"
cite="mid:cf4236ab-7e2b-7be1-c687-222a1fab19dc@comcast.net">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<p>Not trying to reinvent the wheel, David, just get a fuel pump
that lasts. Others have had good service from points pumps like
you, but I haven't. I'm not doing anything unusual; if you get
them installed and they don't leak and they run that's about all
you can do--there's no trick or secret to installing them that I
know of. Mine just keep failing, with between a few hundred and
up to 15K miles of service (this over about 140,000 miles I've
put on my BJ8). I will say I have driven through some serious
downpours, so water entry into the switching compartment could
be a problem, but some of the failures didn't get drowned.<br>
</p>
<p>The points can be problematic, else SU wouldn't have gone from:</p>
<p>1) no arc suppression</p>
<p>2) capacitor arc suppression</p>
<p>3) diode arc suppression</p>
<p>That is to say, SU wouldn't have gone to the expense and labor
of installing capacitors and diodes if there wasn't some issue
with reliability or longevity. I tried all three, with results
as noted. I've installed the out-of-the-box, rebuilt and
adjusted them myself, installed SS switching mechanism, used
capacitors, diodes, TVSes, transistors and installed SU
electronic out-of-the box with predictable results. I do recall
your dad either writing or saying that they used to take the
pumps out and service them--cleaning the points and adjusting
the mechanism I presume--at 15K mile service when he worked at
BMC (or was it BL, don't recall), so they aren't typically
bulletproof forever. </p>
<p>Maybe I pissed the SU gods off somehow; though both my sets of
SU carbs have been all but bulletproof, and the basic
points-type in my BN2 has worked for a few hundred miles.<br>
</p>
<p>Bob</p>
<div class="moz-cite-prefix">On 11/28/2018 9:50 AM, <a
class="moz-txt-link-abbreviated"
href="mailto:healeydoc@gmail.com" moz-do-not-send="true">healeydoc@gmail.com</a>
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:58A4F9749EEA4A8AB6804D8F2053AF09@DavidNockHP">
<meta http-equiv="content-type" content="text/html;
charset=UTF-8">
<div dir="ltr">
<div style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century';
COLOR:
 #000000">
<div>I do not understand the problem with the SU pump that
everyone feels that they have to re invent the wheel. I
have using the standard SU pump with points in my Healey
for almost 75000 miles and never had a failure. </div>
<div> </div>
<div>We also have been installing the standard SU points
pump here at the shop on every car we do for over 40 years
</div>
<div>Everything from Healey’s, MG’s and Jaguar’s and had
very few failures.</div>
<div> </div>
<div> </div>
<div> </div>
<div style="FONT-SIZE: 12pt; FONT-FAMILY: 'Century';
COLOR:
 #000000">David Nock<br>
<a class="moz-txt-link-abbreviated"
href="mailto:healeydoc@sbcglobal.net"
moz-do-not-send="true">healeydoc@sbcglobal.net</a><br>
209 948 8767<br>
<a class="moz-txt-link-abbreviated"
href="http://www.britishcarspecialists.com"
moz-do-not-send="true">www.britishcarspecialists.com</a><br>
<br>
Help us have our Founder Norman Nock inducteed into the <br>
British Sportscar Hall of Fame, You can vote for your
favorites <br>
by visiting the site at.<br>
<a class="moz-txt-link-abbreviated"
href="http://www.britishsportscarhall.org"
moz-do-not-send="true">www.britishsportscarhall.org</a><br>
</div>
<br>
</div>
</div>
</blockquote>
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