[Healeys] Why carry spares

[Bob Haskell]

I sent an email to Dave Dubois and asked if he's done any testing with 
two pumps in series.

If anyone has any long body LCS pumps that their Healey no longer needs, 
I might be interested.  I'm looking for "cores" with undisturbed 
coil/coil housings.  Dirty, non-functional and incomplete is fine. 
Won't make you rich, but will cover shipping in the lower 48.

Cheers,

Bob Haskell
AHCA 3000 Mk I registrar
http://www.ciahc.org/registry_3000mk1.php

On 03/19/2014 09:09 PM, I Erbs wrote:
> Great idea...who has the bits and the time????
>
> Ira Erbs
> IT Educator and Consultant
> Portland, OR.
>
> Sent from my mobile phone. What you get may not be what I typed.
> On Mar 19, 2014 5:14 PM, <rwil at sbcglobal.net> wrote:
>
>> Could it possibly be time for some physical measurements on a test
>> setup to see: what output pressure with two pumps in series, both 2 SU
>> and 1SU and 1Facet (or similar), and in parallel? and what happens
>> when one of the pumps in series packs it in?
>>
>>  From reports here it looks as if SU pumps are pretty patient with all
>> possible setups.
>>
>> -Roland
>> On Wed, 19 Mar 2014 16:01:59 +0000 (UTC), you wrote:
>>
>>> OK, I'm not a theoretical physicist, and don't play one on TV, and we're
>> not
>> talking electronics so I don't see how running two pumps in series doubles
>> the
>> output pressure. AFAIK, the output pressure of an SU pump is determined by
>> the
>> strength of the spring that pushes the diaphragm (presuming the solenoid is
>> strong enough to compress an even stronger spring). There may be some
>> internal
>> 'regulation'--there is a small hole between the input and output chambers
>> on
>> BN1/2 pumps that may provide a pressure limit by bypass--but no real
>> pressure
>> regulation. So, if the spring is capable of producing, say, 3PSI when the
>> solenoid is switched off, then the output to the second pump will, at most,
>> push the spring back some but it wouldn't add to the 3PSI.
>>>
>>> IOW, a spring capable of pushing a diaphragm at 3PSI won't be able to
>> push at
>> 6PSI, just because the incoming pressure is greater. Anyone actually
>> measured
>> the pressure of two SUs in series?
>>>
>>> Bob
>>>
>>> ----- Original Message -----
>>>
>>>
>>>
>>> Two pumps in series might not be suitable for a racing Healey, but they
>> have
>>> worked just fine on my street BJ8 without any problems for a long time.
>>> It's just simpler to plumb them in series than in parallel, in my opinion.
>>> If you have two pumps in parallel with separate switches, then you can run
>>> both pumps at the same time and get twice the flow rate at the same output
>>> pressure. Running two pumps in series at the same time will provide the
>>> same flow at double the output pressure - not good for the carbs. So, for
>>> pumps in series there should be only one switch to prevent running both
>>> pumps at the same time.
>>>
>>>
>>>
>>> Steve Byers
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