Manual fuel pump problem

[alexander]

I'm in the final stages of returning my 1953 Javelin to the road but have hit a problem with the fuel pump. The car came with an eBay electrical pump which over pressured the system so fitted a recon manual one. Works fine when hand primed but no petrol on cranking. Fitted new pin but suspect that wear either on the cam or fuel pump leaver is not allowing the pump to get a full actuation. My question is has anyone else had this problem and how did you solve it. I have a spare leaver and will build the contact area up with weld just to see if that will work.
Thanks in advance for any suggestion
Dave

[Keith Clements]

I had a similar problem with the petrol pump on Peter Pfister's car. I changed the whole pump in the end.
One thing to check is make sure you have a thin gasket and that the faces between block and timing cover are flush.

[alexander]

Thanks for such a quick response Keith, I'm using the gasket that was in the recon kit but you have given me the idea of lapping the pump face that should give slightly more actuation.
Dave

[nigel jarrett]

With the pump removed have you checked that the rod actually moves when you slowly turn the engine over by hand ,just wondering why there was an electric fuel pump to start with .

[Chris Spencer]

Dave - If you cannot get what you have to work - I have a good spare / used pump if want to try it & there is a good possibility that I'm heading up the M40 over the holidays - Chris

[alexander]

Hi Chris ,I have another one or two pump from the spares that came from Jim and have re built two, always good to carry a spare!!! So thanks but should be ok.

[alexander]

Nigel have checked pin and turned car over with the pump outlet pipe removed and get petrol so need to investigate more.

[Keith Clements]

if there is wear, check the oil spray hole in the top of the oil pump is not blocked.

[alexander]

One train of thought I've had which could be wrong but worth a try is that I get petrol when cranking with the petrol pump outlet disconnected because there is no pressure present, once connected there is more resistance and the pump can't manage on cranking but is ok when I hand prime.
will fit other pump and weld and reprofile the pump lever .
Thanks for suggestions and have a great Christmas

[Keith Clements]

simply connect a transparent tube about 4 ft long to the outlet. You should get about 39 inches head both on hand and starter operation.

If not then it is likely to be one of the valves.

[alexander]

Hi Keith finally got back to the Javelin, using your idea of clear pipe I get over 39 inches when hand priming and nothing on turning the engine over so it looks like-there Is wear in the actuating leaver or cam, I fiited a new pin from Jowett spares so that should be correct length. will fit spare pump and test again but that one looks as if there is also wear on the leaver.
Will also weld and reprofile spare leaver and report back.
Dave

[alexander]

Update, built up the actuating lever now have a good 39 inches in plastic tube on turning engine over, just out of interest does anyone know what pressure the petrol pump should be putting out.
Thanks for all the suggestions.
Have a good New Year and with look I will have my first drive tomorrow.

[Forumadmin]

What pressure does 39 inches of petrol give?
Anyhow the pump is really a suction pump having to get the petrol from the tank when climbing a 1 in 4 hill. It only has to pump about 6 inches into the carb bowls. There is probably a spec out there somewhere. Whether there are different valves available for this pump I do not know.

One issue is that sometimes when parking on a hill with tank petrol level above float chambers and with float needle valves not well fitting or bad float, the cylinders will fill with petrol. DISASTER with cracked block ensues. Smelling petrol is a good indicator so always investigate before starting engine. It is also possible that petrol will fill around spark plug and cause a fire.

[PJGD]

Within the accuracy that we are looking for, the density of water = 1, and the density of gasoline = 0.72

Assuming that the 39" head is with petrol, then if it were water we would get a head of 39 x 0.72 = 28"

28" water = 1.01 psi or 6.97 kPa

Philip

[Keith Clements]

Thanks Philip,
On the Jup with the pump midships I have inserted a pressure regulator and set to 1.5 psi.
Here it has to pump up about 30 inches with the car on a hill and a bit more pressure to open the float valves.
Jups with pump on the bulkhead needs a pump that has to suck a lot more.