Fuel system for P2 Tourer

[P4.1958]

In addition to my P4 - 75 from 1958, I now also own a P2 Tourer from 1948.

The previous owner had an electric petrol pump from SU (type AZX1331) installed in series with the mechanical pump from AC.

See sketch



The electric pump should help to get the engine running after a long period of inactivity, otherwise it does not need to be switched on.

Are you familiar with this procedure and arrangement?

The previous owner still has a 14 HP Saloon, in which this configuration is also installed to his satisfaction.

I was previously of the opinion that fuel could not be pumped through another pump. You would have to install an additional bypass.

Who can contribute to this?

Regards
Thomas

 

[colnerov]

The two non return valves in pumps, mechanical or electric, are what makes the pumps work. As they are 'pointing' in the direction of flow they don't hinder the operation of the other pump. In fact, some members on here have electric pumps in addition to mechanical pumps on their P6bs to combat vaporisation stopping the mechanical one pumping.

 

[P4.1958]

The two non return valves in pumps, mechanical or electric, are what makes the pumps work. As they are 'pointing' in the direction of flow they don't hinder the operation of the other pump. In fact, some members on here have electric pumps in addition to mechanical pumps on their P6bs to combat vaporisation stopping the mechanical one pumping.

OK, thanks for explanation.

 

[P4.1958]

I would now want to disconnect the mechanical AC pump and disconnect the copper pipes at A and B.

I would then connect A and B on the pump side with a hose.

Then a pipe separation at C and a new hose from filter D to connection C, which leads to the carburettor.



In the other photo you can see the copper pipe loop to the SU carburettor.

Should you keep the loop and use the new connection C or is it better to run the new hose directly from filter D to the carburettor flange?

 

[colnerov]

The loop acts a flexible connection ie. not rigid which could fracture because of vibration, so I would just connect the filter straight to the carb with a rubber hose. Less connections = less opportunities for leaks. As an aside use a decent hose to deal with modern fuel, I would suggest Cohline hose (R9 or R10) from a reputable dealer, not ebay, there's too much counterfeit stuff about on there.

Colin