Fuel union on P2

[luli]

What type of fuel pump are you using (model, part number)? Where exactly is it located? Note that SU recommends testing the pump on the rig for more than 10 minutes - they know why. What was the temperature of the pump when it was failing?

[RobHomewood]

The new pump is a generic type cheapo which I got just to test the theory that it might be the pump. Model: HEP-02A Installation hole distance :6.7CM Flows: 70(L/h) Currents: 1.2A Voltage: 12V Pressure : 0.032-0 .045 MPA Output Pressure: 3-6 PSI Inlet and Outlet diameter: 8mm.



The previous pump was also an unbranded one which had been fitted by the previous owner and had been working for some years. However the fact the engine failed when I was using the alternative mechanical pump in exactly the same way would indicate to me that it is not the pump itself which is the root of the problem.
The electric pump is fitted to the wing inner opposite the dynamo and the fuel line splits alongside the tank and the electric branch runs in the nearside chassis right to the front and pops up just behind the radiator. The downside of this arrangement is that the outflow from the pump (throttled down to 1.5 or 2 psi) runs along the bottom of the radiator and back to the carb.
To be honest I didn't check the temperature of the pump but it had been running more than 10 minutes and the engine temp gauge was reading about 60 - 65 (with the bonnet open and side removed).
When I said the pump was struggling it suddenly changed tone and the rhythm got more laboured a couple of seconds before the engine died.

[dhbuchanan]

" Generic type cheapo", "an unbranded one which had been fitted by the previous owner"? Hmm.... The next thing you need to do, Rob, in order to give yourself a chance of getting to the bottom of this problem is to get yourself a decent quality electric fuel pump and give serious consideration to the best way of deploying it in your P2. There has been plenty of advice given on this subject in the course of this correspondence.

[luli]

Just to support dhbuchanan I like to add the following: HEP-02A is a high pressure pump which is designed to be installed near and below the fuel tank. It is very weak on suction, and hardly able to elevate the fuel it sucks to where it is now located. On top of it, having two fuel lines makes it even more difficult for the pump, and possibly the source of the air leak. At least put a manual valve, or a non return valve where the two lines split.

[47p2]

Shortly after I bought my P2 the fuel pump was due for replacement, I spoke with the boffins at Burlen Fuels and they told me of all the different pumps available from them and their purpose. I was advised to fit a pump near to the tank that would push the fuel through from the tank to the carburettor rather than one that would go in the engine bay and pull the fuel through. There were two options for the push type pump, the traditional standard points operated pump or the slightly more expensive electronic controlled pump. The electronic controlled pump looks the same as the standard pump but has solid state electronic parts inside instead of the pesky points that always seem to stick so I opted for the electronic model. The pump was changed some 13+ years ago, it cured the hot starting problem, always works and has never faltered once in that time.. Burden will advise on the pressure for your vehicle as well as any other queries and concerns you may have. Worth giving them a call

[RobHomewood]

Oops- even though it was only intended as a temporary test pump I didnt realise I had got the wrong sort - the website wasn't specific but I should have realised but was intent on getting one which didn't need to alter the pipework and fixings - so thanks for that. Perhaps even the one which was on before was an HP sort - it has no reference on it. Anyway I will order the SU pump (what the difference between the AUA25 and AUA66?) In the meantime I will revert to the mechanical pump. I think having a valved switchover on the dual lines would be a good idea so will look at that too. Rob

[RobHomewood]

Alongside still trying to sort other issues I have discovered that the car will only run with the rotor arm 180 degrees out (after cleaning up the adv and retard mechanism). My ignorance will show here because I dont know the correct names of the parts and cannot find a clear diagram. It is the upper shaft with the points cam which sits on top of the fly weights with 2 stud connection which I have had to reverse. Firstly will running like this do any harm? Secondly how has this come about? Is there another part of the shaft which can be reversed? I recently had someone replace the valves (another story) but I did not think he would have either disturbed the timing chain or the camshaft and certainly not the flywheel. Your urgent advice would be appreciated.

[jefflee]

Hi,
Perhaps the flywheel has been off at some time and refitted 180 deg. out.

[luli]

The following picture will help you with the names of the parts:

You can solve the issue quite simply: remove the cam and turn it by 180 degrees. This is best done with the distributor off the car (otherwise droping a little nut can become a big issue).
More pictures here: http://wp.me/pXLKy-25p and the following chapter.

[RobHomewood]

Thanks for the diagram Luli - it shows I was turning the correct part. However I seem to have had a senior moment as having reversed the cam yet again the timing mark seems to be correct now. My head is full of petrol fumes and under pressure! I think though I have finally discovered why the car is fading and dying - fuel starvation. It seems the fuel pressure regulator is faulty and closing down totally when hot and/or collapsing the rubber pipe between it and the carburettor. (Both are clear when I disconnect them) This section of pipe is the only section I have not replaced yet and is mesh covered rubber so I don't know how old. I wonder - if the regulator blocks off the supply totally whilst running whether the suction from the engine is enough to collapse a slightly tired pipe? It doesnt explain the air bubbles in eth fuel line before the regulator unless that is a cavitation effect? I dont need the pressure regulator now I have the correct SU pump and I shall replace the pipe anyway and hope to report being back on the road shortly,
Rob