Fuel Pump choice.

[Stratton Jimmer]

On 24/02/2022 at 17:31, daverclasper said:

apparently a 3mm gasket, to space it, has cured the issue

That was me. I have since changed the pump for a spare which came with the car when I bought it and this one is fine with a standard gasket, My 3mm home made gasket sprang a leak. Only thing is, I cannot see any physical difference in the two pumps so that's a bit of a puzzle as to why one is fine and the other caused the carbs to flood. (Note the carbs are SU HS6).

[68vitesse]

21 minutes ago, Stratton Jimmer said:

That was me. I have since changed the pump for a spare which came with the car when I bought it and this one is fine with a standard gasket, My 3mm home made gasket sprang a leak. Only thing is, I cannot see any physical difference in the two pumps so that's a bit of a puzzle as to why one is fine and the other caused the carbs to flood. (Note the carbs are SU HS6).

Probably a difference in the strength of the spring under the diaphragm.

Regards

Paul

[Wagger]

Obtain a pressure gauge and measure at the carbs. Some of us have had problems with over pressure and under pressure. Mine was crud from the tank when using 'Reserve' setting on my Vitesse, plus a bit of water. That caused flooding and blockage on one carb so ended up running on three cylinders. I now have a filter at the tank outlet and one in the engine bay before the pump. Transparent and 2 inches in diameter so I can see problems before they happen, I hope.

[Unkel Kunkel]

On 20/03/2022 at 10:02, Stratton Jimmer said:

That was me. I have since changed the pump for a spare which came with the car when I bought it and this one is fine with a standard gasket, My 3mm home made gasket sprang a leak. Only thing is, I cannot see any physical difference in the two pumps so that's a bit of a puzzle as to why one is fine and the other caused the carbs to flood. (Note the carbs are SU HS6).

Pressure:

The mechanical pumps now supplied develop  more pressure than original  specification  resulting in carb. flooding.

(I posted about this the other month or so)

I checked my new  pump .. = nearly 7 psi

 

Should be :2.5 -3.5 :

This is well outside spec.

( The suppliers must be aware of negative feedback about this.

1.They have a responsibility to supply goods to spec.

2.They are ignoring the obvious safety implication caused by fuel leakage)

I reduced it by gaskets as per above- it is in the repair manual  as above - and does work.

The root cause is the spring under the diaphragm - it is stiffer in the” new” pumps .( I tested them with weights needed to compress)

So, next  I swapped the spring from my old pump, went back to a standard thin gasket.

It was fine but by now I had a Malpassi Filter King on order to regulate the pressure -and filter, so fitted it too:

 

 

The other disappointing thing about these pumps - the pump operating arm which runs on the engine cam shaft = disappointingly finished - very ridged/rough - does need a bit smoothing/ finishing  before installing to save excessive wear on the cam.

 

 

[johny]

'The other disappointing thing about these pumps - the pump operating arm which runs on the engine cam shaft = disappointingly finished - very ridged/rough - does need a bit smoothing/ finishing  before installing to save excessive wear on the cam.'

On many after market pumps the arm is also half the thickness of the original and I read a post somewhere about a groove being worn quite rapidly in the cam...