fuel pump pressure.

[vin16660088]

Hello, i have a few fuel pumps of varying types that came with the landrover. there are a few high pressure (HP) and a few smaller types which i pressume is the normal pressure, what is the right one for a 2 liter engine or does it even matter.

I have been given a different option as well, to mount the SU pump in normal position but don't connect to the electrics, while still running the fuel line through the SU and hook up a modern inline pump out of sight so you have a more reliable system with out changing the looks, might be a better way to go all together. cheers. Anthony.

[chazza]

The low pressure pump should be the one to use I suspect. Too high a pressure will force fuel past the float needle and cause the carburettor to flood.

Your alternative using a modern pump is a good one, especially if fuel vaporisation is a problem with the SU pump. The pressure off a modern pump needs to match the old system.

My Land Rover manuals do not specify a fuel pressure, but I seem to recall that about 2psi worked well on Morrises also using the SU pump and SU carburettor,

Cheers Charlie

[Blknight.aus]

generically the fuel delivery pressure for a petrol rover engine (2.25 and the like ) should be between 4 and 7 psi.

[gromit]

When I first got my Series 1 it had dual Facet pumps (it has an additional fuel tank under the tub) but the high pressure was causing problems.
I ended up fitting a pressure reducer in the line set to about 3.5psi (only because the father-in-law donated it), car ran much better.

If you intend to pass through the SU pump are there valves that need removing ? I ask because I intend to hide the Facets and do much the same thing.

Colin

[Scouse]

If you intend to pass through the SU pump are there valves that need removing ? I ask because I intend to hide the Facets and do much the same thing.

No, the fuel will flow through just fine.

It's a common mod on Morries with Historic Plates where the engine bay needs to look original.

[vin16660088]

Thanks for the replys, i was finding it hard to track down any information about pressure, the way the in line fuel pump was explained to me is that it will pass through normally as long as you pass the fuel through the right way so that the diaphram alows the fuel to pass through, so a low pressure fuel pump would be the go, is there an exact flow rating for a 1953 2L, i cant find any reccomended pressures anywhere.

[series1buff]

hI aNTHONY

I have been through the wringer , with my experiences of SU pumps on these cars . I will try to summarise what I learnt . First, many people told me to ditch the original pump.. no good, rubbish, never work properly they said . No matter what you do, they are unreliable .. so on and so on.

Now, if you talk to the actual people who have used them on series 1's for 40 years or more, they will tell u whats what , not furphy stories . They work fine .. if adjusted correctly , fitted with new diaphram and points .

Those pumps were around pre WW2 , in Morris and other makes , the early ones usually have a brass main head.

You need the normal LP version for starters , the HP version will cause flooding problems .The pressure should be around 1.5 to 2.5 not any higher than that . Most mechanical pumps work at around 4 or more .. that's too high for your car ( thats if your running the original carby ) .

I have found them to very maintenance friendly, you can remove the amarture assembly be pressing it out of the main body, very easy . Some of them have a cheap enamelled insulation over the armature winding as per generators .. I would be suspicious of these as the enamel can easily wear off and cause shorts . The other type I have come across uses thick cotton insulation on the windings .. these are far better to use . Another option is: you can easily unwind the old wire and get some new wire from a place that re-winds armatures, just measure the gauge and length of the wire ( and its resistance in OHMS 2 from memory ) from the old armature, its wound a simple bobbin like thing .

I got a kit from Gower and Lee , a UK firm who sells all this stuff . The kit is genuine SU brand , comes with all u need . They went to twin points in an attempt to split the current between two points, rather than use the single points .. the twin points just fit in and replace the old single type .

Just follow the instructions and adjust per the specs, and it will run happily .. There are modern solid state electronic version SU pumps around .. at close to $200 ..These are polarity dependant however .

Mike

[vin16660088]

Thanks mike, i might give it a crack, if i stuff one up ive got a couple of spares, ive been told they make a nice ticking over sound (i have never seen or heard one) when working, just another sound under the bonnet that cant be replicated i suppose. Cheers. Anthony.

[series1buff]

Just some more info: we had a long discussion on these pumps on the old email based list a few years ago . All sorts of theories were put forward .

The experts worked out that the design of these pumps is such that: the pressure that the needle and seat sees, or looks at , is almost wholly dependant on the tension in the pump diaphram spring . The condition and tension of the spring that sits in front of the diaphram is critical. That's why its best to buy a kit , which has a new spring in it .

BTW the kits from Gower and Lee are about half the price of a kit from that NSW place , and that includes postage.

Sometimes the two faces where the diaphram seals against - the head and main body, get pitting on them. To fix this, you can use a piece of plate glass and some medium grade wet/dry abrasive paper . Lay the paper on the glass, and use some kero or WD40 and slowly push the faces around over the paper . You can reface carby bits too . Plate glass is optically flat .

Mike

Mike

[dennisS1]

As Mike stated, a properly adjusted low pressure pump will last for years without a problem, much better idea then the poxy solid-state new things that want the polarity to be the wrong way.
Replace the diaphragm, clean up the faces and the small brass disks, adjust as per book and will work for 10 years min.
You can buy a kit or the ruber material, and on the original units the brass stem will unscrew and you can replace it.
Dennis