Electric fuel pump conversion for 1256 engine.

[tynelord1969]

Has anyone knowledge of replacing a mechanical fuel pump with an electric one?

I have replaced my old mechanical one with 2 new ones and neither work when connected to the engine ( they work fine if I move the activating arm by hand), so there is a problem inside the engine . I have put an extra heat insulator on and still no fuel comes out of the pump, so there must be a problem with the camshaft.

Does anyone know of a specific type of electric pump that would be suitable and if so where is it best to fit it as I 've read that they should be as low as possible to the fuel tank?

Thanks,
Leon.

[1972nail]

Facet do nice simple plastic (corrosion proof) pump for carb engine that will flow enough for 40 to 180 bhp. About £30. You'll need a 5a fused ignition controlled supply and a safety impact cut off switch to make it safe. Second hand switches from a Mini, Fiesta, Rover 200 plus loads more are OK but get the wiring plug with them.

Fit the pump in front of the tank above the axle and the safety switch in an accessible place inside the car, boot OK but more likely to activate up front in the engine bay in the event of a crash.

Are you sure that you're not hooking the lever behind the cam instead of on top of it?

[pbottomley]

dont get the top of the range pumps as they pressurise the fuel line more than the carb can handle. either get a pump ranged at 3psi to 5psi or fit a regulator at the engine bay end of the fuel line.

[ADRIAN]

The standard mechanical pumps are perfectly fine if they are fitted correctly. Firstly, you must ensure the operating arm sits on TOP of the camshaft inside the hole in the block. If mounted underneath the cam, the pump will only operate at the lowest point of the stroke (only about 10% of the stroke). Secondly, all the rubber hoses attached along the fuel lines, rubber must be new and supple and the hose clips well tightened. If the hoses are old and hard and the hose clamps are not gripping tight enough, the pump will just suck in air and wont pump up the fuel.
Adrian

[Paul Dawson]

I used a fuel pump from an old Mini in my Triumph. It had the added bonus of priming the fuel flow after it hadn't been run for a while. I just bolted it to the inner wing in the engine bay.

[GAV]

I have run an electric fuel pump since fitting my rebuilt engine on my HB. I think I got it on Ebay for about 12 pounds inc P&P however fitting a blanking plate to the old outlet had caused some leak issues as its remounted on the bulhead rail.
I even tried removing the drive arm off the mechanical pump and buying a spacer which promptly cracked and split in half /but I think the blanking plate has more or less sealed now.
Also there were some carb issues with the zeniths Have about six now,after it stalled and refused to restart got a friend to tow me home changed the carb again, then decided to fit electronic ignition as also the points were causing problems when it stalled again down the road.
Went to a show in it thereafter and having been requested to back up into a space the dang thing refused to rev. Some kind guy with loads of tools,a mechanic off duty and I checked the carb but couldnt get the idle needle screw to budge.

I went to have a look see in the autojumble and got an identical Zenith for a tenner, with a good inlet manifold joining spacer, my one came apart when taking the carb off. Revs restored and quite a few folk congratulating me ,one young guy I never saw before commenting I knew you’d do it, however I bought the good Samaritan a beer and chatted before leaving also with his mate who he had just done some swap for a Viva with.

When leaving however the thing stalled at junctions but was ok on the A12 so on arrival home took the carb venturi off and found an old fashioned metal float was detatched from the springy flap and was free floatin,so changed it for a good plastic one,and found the idle jet could be removed so cleaned the jets at the same time.
I had been loath to risk damaging the main gasket at the show,as the one on the previous carb split and I have a dozen or so solex ones but zenths seem hard to find.
The car was fine ,however I was on my way to join a local club cruise to Wattisham from a Diner off the A12 and at the Horsely Cross roundabout on the A130 the Viva cut out.
A Father and son stopped and helped me push the car into a layby opposite. I said I had breakdown recovery however he ventured if I was still there when they returned from Colchester he could tow me home.

I knew my Cresta owning friend had gone to the Diner but he and wife werent doing the run because of their dog ,rang him and he was just leaving the diner in their Rover 75 and would tow me home, however, in the interim I found one of the bayonet clips onto the new coil I also got with and from the Sparkright ignition, was loose ,so crimped it rang my chums and cut across country ,despite the car seemingly only running on 3 pots( it was an HT lead into the dizzy cap had worked loose too), but I arrived at the x Raf, x Sea rescue base just before the club convoy.

Also the choke cable got too frayed with all the carb swapping so was running without one. As I use my Viva all year around I took a chance on a Webber one which works fine.

My Mondeo finally got to the end of the road and is gone, a Renault Van I used to transport motorbikes to Scotland and The Isle of Man in has an imobiliser issue, so after also fine tuning the carb and three weeks of unwellness myself not going out ,I was very pleased that the Viva started third turn of the key, as I probably hadnt got the choke right, and the starter motor doesnt always catch( another job but great I bought a box of bits of a member locally inclusive of a virtually new starter motor.
When folk say oh those old cars you could work on em yourself, not like this modern stuff, yes true but then you do hsve to work on em a whole lot more to keep on top of things.

Anyway keep percervering with the HC I do have a new HC petrol pump also a new locking petrol filler cap for an HC if you or anyone needs one incidentally.

[tynelord1969]

Facet do nice simple plastic (corrosion proof) pump for carb engine that will flow enough for 40 to 180 bhp. About £30. You'll need a 5a fused ignition controlled supply and a safety impact cut off switch to make it safe. Second hand switches from a Mini, Fiesta, Rover 200 plus loads more are OK but get the wiring plug with them.

Fit the pump in front of the tank above the axle and the safety switch in an accessible place inside the car, boot OK but more likely to activate up front in the engine bay in the event of a crash.

Are you sure that you're not hooking the lever behind the cam instead of on top of it?

Thanks for the advice. I'd much rather use a mechanical fuel pump, but feel I have no option as I've tightened all the flexi pipe jubilee clips and replaced the original rubber section from the steel pipe to the inlet pump pipe. There was an old petrol leak ( when I must've had much more petrol in the tank) which had washed away the paint/underseal where the fuel leaves the tank, and the connection was a bit loose. Is there a seal that is fuel resistant that can be used to make the joints more air tight? Also is PTFE tape compatible as one of my new pumps has narrower 1/4" pipes rather than the bigger 5/16" diameter?

When I was fiddling with a new pump and trying to position it correctly to align the bolts, I noticed small amounts of fuel coming out of the pump outlet pipe, as the activating arm must have been pushed, but as soon as I fit the pump to the engine the pump doesn't work. I have tried positioning the pump activating arm in different ways , but the pump only seems to go in place in one position. The Haynes manual says to make sure the arm is positioned on top of the camshaft, which is what I've been trying to do, but maybe I'm trying to position it too high, although the pump only seems to go in one way.


The car has done about 80,000 miles so I wouldn't have thought the contact area of the camshaft would have worn away so soon.


It's all very frustrating!

[tynelord1969]

Hi there.

Thanks for all the replies. I'll have another go at fitting a new mechanical pump, but I can't see it going in any other way as to how I've been trying. I've put my main reply to one of the member's comments.

Thanks,
Leon.

[ADRIAN]

When fitting the pump, put the spacer on the pump with a gasket either side all smeared with thin coat of Hermitite or Hylomar sealant equivalent. Put the operating arm into the hole at the very top of the hole, and once the assembly is up against the block push the body of the pump downwards in order to line up the two bolts in their holes then tighten them up with spanner whilst holding the pump with the other hand to stop it moving. Can be a bit fiddly and difficult but it ensures the arm goes onto and stays on top of the cam where it is supposed to be, Fit petrol pipes onto the feed side of the pump only, then, with ignition wires disconnected at solenoid for safety, operate the starter. The pump should eventually pump up, squirt petrol out with force like a fountain, not a dribble . If it doesn't squirt, - the pump is faulty.
Another thought to check, If the pump you have is the incorrect type, in other words for another car, like for instance a Triumph Herald pump, the operating arm will be at the wrong angle. Only a slight difference in the angle of the arm will mean that it wont pump fuel, as the arm will be pushed more sideways by the camshaft lobe rather than lifted up as it should be on a Viva engine.

[Paul Dawson]

Thinking back to when I fitted the pump to my Triumph I had the same issue, I tried several mechanical pumps all of which were supposed to fit the engine but none of them worked. Hence going electric. The joy of parts manufacturers in those days.