[Healeys] Why carry spares

[Chris Dimmock]

Yep Kees.
You are correct. Accurate.
I deliberately ignored the exact wording of the question. Deliberately. It's
NOT about pressure. It's about VOLUME of fuel. Listers are looking for a
backup pump. A backup hot or cold spare fuel pump.
What's the pressure an SU carb requires Kees?? Or a weber? That would be 3 or
4 psi.
What happens if you provide 8 or 10 or more psi fuel PRESSURE to an SU carb??
What happens?
The answer is - Fuel pisses out everywhere!!!!
Easy diagnosis. Help!! There is fuel pissing out everywhere in my engine
bay??? No one asked that!!!
So it's actually about fuel volume.
So I addressed that question.
If fuel is pissing out of your Carbs, please extinguish your cigarette, and
shut down your fuel pumps. Ok??
Yes. Pressure is important. But this thread is not about a bunch of blokes
complaining about fuel spraying all about their engine bay!!!!!!!!
So rather than carrying on about on a theoretical flow bench, to measure
pressure - let's just cut to the chase on a Healey 3000 with pumps in
parallel. Pumps in series. Double ended pumps.
People who have these setups.
It's easy to measure fuel flow!!!!
I have a pressure regulator, which is how the car was setup. And I'm not
changing a winning formula...
I know know it's not an issue with SU pumps. The issue is fuel volume.
Let's measure that.
You first Kees
How much fuel does your fuel pump setup deliver on your 3 litre
Healey?????????
I'll measure mine on the weekend. Double ended SU pump, with a Malpassi
pressure regulator.
The issue is volume. Not pressure.
Of course Kees, if your 3000 is pissing fuel out from its SU's - then pressure
is probably your problem...
And put our the cig, and shut the welder off!!
Sincerely.
Chris

Sent from my iPhone

> On 20 Mar 2014, at 6:54 pm, Oudesluys <coudesluijs at chello.nl> wrote:
>
> Chris,
>
> That would be a flow test, not a pressure test, which is certainly not the
same.
>
> For a pressure test you would need a fuel pressure gauge to measure the
output pressure of :
> 1: one single pump, nr. 1
> 2: one single pump, nr. 2
> 3: two pumps in line, nr. 1 pump switched on  and nr. 2 pump switched of,
the result should be similar to test 1
> 4: two pumps in line, nr. 2 pump switched on  and nr. 1 pump switched of,
the result should be similar to test 2
> 5; two pumps in line, both pumps switched on, the result should be the sum
of test 1 and 2
>
> In all test situations the flow should be more or less the same, depending
on the resistance in the output line. You would only double the flow if you
have the pumps fitted in parallel.
>
> It is assumed that Lucas type pumps are used. Other type of pumps may give
different results in test 3 and 4 and the flow test. E.g. gear and vane type
of pumps may show no or little flow and pressure in these tests as they will
(partially) block the fuel line when not switched on.
>
> Kees Oudesluijs
> NL
>
> Chris Dimmock schreef op 20-3-2014 3:10:
>> It's pretty simple to test.
>> Just disconnect the fuel line, point it into a bucket, turn the one pump
on,
>> run it for 30 seconds, and measure the volume of fuel in the bucket.
>> Empty the bucket.
>> Then turn both pumps on, run them for 30 seconds, and measure the fuel
pumped
>> into the bucket.
>> Report back here.......
>> That volume of fuel x2 is the delivery volume per minute.....
>> X 120 = volume per hour.
>> It's not Formula one, close enough is good enough, you won't get in
trouble
>> with the FIA....
>> Easy.
>> Best
>> Chris.
>>
>> Sent from my iPhone
>>
>>> On 20 Mar 2014, at 11:14 am, rwil at sbcglobal.net wrote:
>>>
>>> Could it possibly be time for some physical measurements on a test
>>> setup to see: