[Healeys] Fuel pumps (AGAIN!)

Thu Nov 29 03:43:15 MST 2018

Good point!!

Never had this kind of problem but it could well be a cause of damage to 
the coil.

Kees Oudesluijs

Op 29-11-2018 om 05:26 schreef Michael Salter:
> This discussion about fuel pumps has revived something from the old 
> grey matter ...
> To those mentioning repeated failures one problem that will cause 
> premature failure is restrictions in the supply to the pump.
> The way these pumps work is that the spring in the pump provides the 
> pressure. As the pressure on the output side of the pump decreases the 
> diaphragm moves down to a point where the points close, that energizes 
> the coil to pull the armature up against the spring pressure to the 
> point where the points "flip" and open to stop the current flow 
> through the coil.
> HOWEVER if there is a restriction in the fuel line feeding the pump 
> the low pressure at the pump inlet can create a partial vacuum which 
> will prevent the armature from rising fully and thus the points from 
> "flipping" .
> When this happens the coil remains energized and "cooks" in a short 
> time thus ruining the pump.
> I discovered this while trying to resolve a delivery problem in a car 
> that had had the tank "sloshed". The sloshing compound had coated the 
> gauze filter  inside the tank severly restricting the flow.
> The test was to put an analogue ammeter on the pump electrical supply 
> which showed the prolonged current flow to the pump.
>
> M
>
> On Wed, Nov 28, 2018, 9:45 PM Kees Oudesluijs <coudesluijs at chello.nl 
> <mailto:coudesluijs at chello.nl> wrote:
>
>     Quite so. The only thing I can come up with is the car is hardly
>     being used and being stored in dampish non ventilated conditions,
>     thus corroding the points. As I said before I have had SU fuel
>     pumps in from more than 50 years old which were absolutely perfect
>     except for the points corroded because the car was not used enough
>     or worn because of not being adjusted properly.
>
>     If used regularly and kept dry internally they last forever.
>
>     Another thing: If you have had to tap the pump to get it going,
>     replace/polish and adjust the points ASAP. Do not wait until you
>     have to repeat the tapping.
>
>     When fitting a new SU-pump you best remove the cap to inspect and
>     if needed clean the points first with very fine polishing paper, I
>     use at least 1000. It is even not uncommon that brand new pumps
>     that have been on the shelf for a while, either at home, in the
>     garage or at the suppliers do not work because the points are
>     dirty/corroded and have to be attended to first. I have bought
>     many pumps that were sold as "defective, for spares or repair" 
>     for a song, that did not work and appeared to be in fact NOS.
>     Cleaning and polishing the points was all that was needed for
>     these. If you have a new/rebuild spare pump in store , remove the
>     cap and insert a bit of acid free paper in between the points,
>     this will stop electrolytic corrosion.
>
>     In the late 70´s I was collecting  quite a lot of Jensen parts and
>     got presented a new pump by Jensen Parts & Service that was said
>     to be defective but only needed some small attention. My old pump
>     kept working (more than 160000mls) so the new pump was never
>     needed. About 5 or 6 years ago I came across that pump and decided
>     to have a look inside. It was of course mint but there were real
>     cauliflowers around the points. Just polished them, fitted a
>     transil (as I do with all my rebuilds) and is now in my present car.
>
>
>     Kees Oudesluijs
>
>
>
>     Op 28-11-2018 om 18:50 schreef healeydoc at gmail.com
>     <mailto:healeydoc at gmail.com>:
>>     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.
>>     We also have been installing the standard SU points pump here at
>>     the shop on every car we do for over 40 years
>>     Everything from Healey’s, MG’s and Jaguar’s and had very few
>>     failures.
>>     David Nock
>>     healeydoc at sbcglobal.net <mailto:healeydoc at sbcglobal.net>
>>     209 948 8767
>>     www.britishcarspecialists.com <http://www.britishcarspecialists.com>
>>
>>     Help us have our Founder Norman Nock inducteed into the
>>     British Sportscar Hall of Fame, You can vote for your favorites
>>     by visiting the site at.
>>     www.britishsportscarhall.org <http://www.britishsportscarhall.org>
>>     *From:* Tom <mailto:ah3000me at gmail.com>
>>     *Sent:* Wednesday, November 28, 2018 6:00 AM
>>     *To:* healeys at autox.team.net <mailto:healeys at autox.team.net>
>>     *Subject:* Re: [Healeys] Fuel pumps (AGAIN!)
>>     I found the voltage regulator was misadjusted when i got my car. 
>>     At 17V, a new pump quit working in less than a year.  At 14V, the
>>     replacement is 10 years old and happily ticking away.
>>     Tom
>>     On Tue, Nov 27, 2018, 9:16 PM Frank Magnusson <fmags at cox.net
>>     <mailto:fmags at cox.net> wrote:
>>
>>         Hi Bob,
>>
>>         I’m also not sure why you’re having problems with pumps. 
>>         Maybe something common between all of them; the vent, the
>>         ground, the venting of the fuel system, etc.
>>
>>         I replaced my original pump in the late 80’s with a stock SU
>>         pump with points and it’s been on the car ever since; no
>>         problems except last year when it didn’t want to start, but a
>>         rap with a rubber mallet and it’s been working ever since.
>>
>>         Try Healey Surgeons for a replacement pump.  Their parts are
>>         100% correct and I’ve never had a problem with anything from
>>         them in almost 30 years.
>>
>>         Best of luck,
>>
>>         Frank
>>
>>         ’65 BJ8
>>
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