LarryH57 Posted February 7, 2015 Share Posted February 7, 2015 (edited) We are fitting an electric fuel pump to a Hillman Tilly, in place of an AC engine driven pump, and I'd like to know what psi approx. would do. I imagine its got to be fairly low pressure for the type of engine. Has anyone done this to a Tilly or similar type of vehicle? Once I know what psi, I can then order one from firms like Southern Carburettors, who have a few positive earth types. BTW I have also seen pumps rate in litres or gallons per hour. Which is a better way of assessing an electric fuel pump? Edited February 7, 2015 by LarryH57 Quote Link to comment Share on other sites More sharing options...
fayjo56 Posted February 7, 2015 Share Posted February 7, 2015 Burlen Fuel Systems of Salisbury would be a good place for advice. Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted February 7, 2015 Share Posted February 7, 2015 Burlen Fuel Systems of Salisbury would be a good place for advice. Agreed. They supply S.U. pumps, now in both mechanical and electronic form. Here is link to the technical data: http://sucarb.co.uk/technical-su-fuel-pumps-history Note Low press pumps are rated at 1.5psi, plenty good enough to replace a mechanical lift pump (I've used them on a couple of ww2 engines). I believe 3 - 4 psi is enough to overcome the float shut-off needle valve of most ww2 carbs? So best steer clear of the HP version. Quote Link to comment Share on other sites More sharing options...
RMS Posted February 8, 2015 Share Posted February 8, 2015 I find it best to use a good quality (Facet/SU) low pressure pump and then fit a filter/regulator (Filter King) after the pump, it reduces the pulse effect of the pump on the needle valve and you can set the pressure from 1-4 psi, works great. Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted February 8, 2015 Share Posted February 8, 2015 (edited) I find it best to use a good quality (Facet/SU) low pressure pump and then fit a filter/regulator (Filter King) after the pump, it reduces the pulse effect of the pump on the needle valve and you can set the pressure from 1-4 psi, works great. I tried this on a recent job, but had to abandon the very nice Filter King filter/regulator because it is just about impossible to alter the angle of inlet / outlet pipes due to filter housing construction and we only had one suitable place to locate the unit. The filter on the S.U. pump is not the best to rely upon and needs a better filter somewhere in the line. :argh: We used an inline filter between tank and pump to save potential problems with clogging the minuscule pump filter but your point about reducing pulse between pump and carb is a very good one. Despite looking hard, there doesn't seem to be a decent alternative to the Filter King out there. :??? Edited February 8, 2015 by N.O.S. Quote Link to comment Share on other sites More sharing options...
RMS Posted February 8, 2015 Share Posted February 8, 2015 yes i know what you mean, you can get inline pressure regulators as well, they work just as well and can be hidden quite easily. Quote Link to comment Share on other sites More sharing options...
Don Robert Posted February 8, 2015 Share Posted February 8, 2015 I don't know why everyone is making this so complicated. A standard electro-mechanical or solid state fuel pump SU. pump, pumps at 3-4 psi...broadly compatable with the output of a good AC type engine driven pump. Millions apon Millions of British cars from the 1930's to 1970's ran either into a SU or Solex type carb with a bogo float chamber and needle valve . From my own experience these did not flood at the drop of a hat or needed "Pressure damping " or additional filters. Filter kings etc were intoduced into the market initially to help "extreme " operation vehicles such as Land Rovers or Competition cars which experienced high "G" loads that could cause temporary unseating of float chamber needle valves and subsequent "over rich" operation. A SU pump readily available new or second hand will work fine. If you need a filter sort the tank out. If it floods sort the carb. out. Keep it simple. Quote Link to comment Share on other sites More sharing options...
Blackpowder44 Posted February 8, 2015 Share Posted February 8, 2015 I don't know why everyone is making this so complicated. A standard electro-mechanical or solid state fuel pump SU. pump, pumps at 3-4 psi...broadly compatable with the output of a good AC type engine driven pump. Millions apon Millions of British cars from the 1930's to 1970's ran either into a SU or Solex type carb with a bogo float chamber and needle valve . From my own experience these did not flood at the drop of a hat or needed "Pressure damping " or additional filters.Filter kings etc were intoduced into the market initially to help "extreme " operation vehicles such as Land Rovers or Competition cars which experienced high "G" loads that could cause temporary unseating of float chamber needle valves and subsequent "over rich" operation. A SU pump readily available new or second hand will work fine. If you need a filter sort the tank out. If it floods sort the carb. out. Keep it simple. I couldnt agree more, all this angst over pressure etc. I have fitted Su electric pumps to jeeps, and if i could not one I fitted an electric pump from a Jap saloon, make unknown. All the jeeps have been fitted with an electric pump for years and have not given any trouble, John. Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted February 8, 2015 Share Posted February 8, 2015 (edited) So to summarise, Larry - You need a low pressure (1.5psi) pump You could use a high pressure (4psi) pump You could fit a filter which incorporates a variable pressure regulator so if need be you can adjust You don't need a regulator You need a filter You don't need a filter That about covers it I think? :rofl: Edited February 8, 2015 by N.O.S. Quote Link to comment Share on other sites More sharing options...
paulbrook Posted February 8, 2015 Share Posted February 8, 2015 Most engine driven fuel pumps of the day were rated at 2psi if that's any help... Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted February 8, 2015 Share Posted February 8, 2015 I've put Facet solid state pumps on loads of vehicles, from Land Rovers to Ward laFrances and never used any form of external pressure regulation. You just need to be sure your needle valve is in good nick. If you size the pump correctly from the huge range available you won't need anything else. I agree the little filter that screws directly into the pump is inadequate - fit a good quality 1.5" diameter clear plastic one in-line before the pump and carry a few spares in the glove box. 1.5 to 2 psi should be fine but talk to Southern Carbs if you're unsure. - MG Quote Link to comment Share on other sites More sharing options...
Starfire Posted February 9, 2015 Share Posted February 9, 2015 Just make sure you avoid the real high pressure EFI type pumps, they will cause all sorts of problems with a carb (such as large quantities of uncontained fuel and fires). The other thing to be wary about with electric pumps is that unlike a mechanical pump, or a modern EFI pump hooked up to an appropriate computer, they do not stop pumping in the event that the engine stops. This is particularly dangerous in the event of a crash or fuel leak, as fuel will continue to flow until the ignition is turned off. There are a number of products available that will cut off fuel pumps in the event of an accident. Cheers, Terry Quote Link to comment Share on other sites More sharing options...
Ron Posted February 9, 2015 Share Posted February 9, 2015 (edited) I worked as a motor mechanic in the 60's/70's. A Morris Minor is an equivalent size engine and they always had an SU electric fuel pump mounted on the bulk head. Mini's and Jags for instance had them at the rear of the vehicle and were therefore pushing rather than pulling and I think were rated differently. They all had to be mounted horizontal. So I would just buy the one suitable for a Moggy as they must still be available above all others and mount it in the engine bay. Ron Edited February 9, 2015 by Ron Quote Link to comment Share on other sites More sharing options...
paulbrook Posted February 9, 2015 Share Posted February 9, 2015 Oh and I forgot to ask - why are you doing away with the original pump? They are easily refurbished and kits are available (and a kit only has about 5 parts in it!) Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted February 9, 2015 Share Posted February 9, 2015 While you wait for Larry's reply, the reason I've done away with some pumps is because I was unable to source a pump with a priming lever. On an infrequently used vehicle this is a flippin' nuisance. When I can get a priming type pump I'm happy to use one. Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted February 9, 2015 Share Posted February 9, 2015 The principal advantages to me of installing a solid state pump on an older vehicle are that it replaces the rubber in the lift pump diaphragm which is one of the favourite foodstuffs of ethanol fuel; it also virtually eliminates vapour locking on vehicles prone to this. NOS's point about priming levers is also very important as it avoids unnecessary churning of a cold, tight engine just to get fuel up. It is good to get the oil moving around an engine before starting from cold but I prefer to so this on my own terms by cranking the engine with the ignition switched off rather than being forced to by the fuel having evaporated or run back. - MG Quote Link to comment Share on other sites More sharing options...
LarryH57 Posted February 9, 2015 Author Share Posted February 9, 2015 Guys, firstly thanks for all your replies. Sadly the cam on the camshaft in the engine of the Tilly must be worn down as it no longer pushes on the push rod sufficiently to pump the AC fuel pump, which itself is in good order. We may decide to go back to the AC if the engine needs stripping. But for now we want to get the old girl mobile hence the need for an electric pump. BTW - Regarding the problem that electric pumps do not stop pumping in the event that the engine stops, we propose to have one connection attached to the coil, so in the event of a stall or crash, the pump will stop. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted February 9, 2015 Share Posted February 9, 2015 Guys, firstly thanks for all your replies. Sadly the cam on the camshaft in the engine of the Tilly must be worn down as it no longer pushes on the push rod sufficiently to pump the AC fuel pump, which itself is in good order. We may decide to go back to the AC if the engine needs stripping. But for now we want to get the old girl mobile hence the need for an electric pump. BTW - Regarding the problem that electric pumps do not stop pumping in the event that the engine stops, we propose to have one connection attached to the coil, so in the event of a stall or crash, the pump will stop. Larry, you seemed to have condemned the camshaft, but doubtful if you have physically seen it. Have you measured the stroke of the pushrod? Then measured distance from pump mounting face? Once you have these details, then measure the pump and see far it strokes the diaphragm lever. If the cam is worn it might send alarm bells ringing as to wear on other lobes of the cam. Regarding your wiring idea, the pump will still get power from the coil terminal until the ignition is turned off. Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted February 9, 2015 Share Posted February 9, 2015 The best solution is to fix whatever is wrong with the original setup, pushrod, cam, whatever. Every time I have seen someone retro-fit an electric fuel pump to a system not designed for it they have had problems, nearly always related to excess pump output pressure overwhelming the carb. If you have to go electric, low pressure ... Quote Link to comment Share on other sites More sharing options...
LarryH57 Posted February 9, 2015 Author Share Posted February 9, 2015 With the AC pump off and the engine turned over, the push rod hardly moves. I put my finger over the end and there was so little movement it was understandable it was not going to move the cam on the pump. With the pump in place it was possible to hand pump the carb but as soon as I stopped the engine dies. So what else can I do? Quote Link to comment Share on other sites More sharing options...
Starfire Posted February 9, 2015 Share Posted February 9, 2015 Is the cam lobe worn or is it the follower on the pump? I would say that is much more likely. If you're looking for a device to control the fuel pump based on an ignition signal, you need a tachometric relay. Cheers, Terry Quote Link to comment Share on other sites More sharing options...
TooTallMike Posted February 9, 2015 Share Posted February 9, 2015 The cheap way to do it is to use an electric oil pressure sender to fire a relay when there is oil pressure. This can go in a spare port in the block or tee into the pressure gauge line or whatever. If the engine dies the pump is switched off. The big disadvantage is that you're back to churning the engine before you have enough oil pressure to fire the relay to get fuel up, but as I say, it's a cheap solution if it worries you. - MG Quote Link to comment Share on other sites More sharing options...
Ron Posted February 10, 2015 Share Posted February 10, 2015 Live dangerously! Millions of cars were produced without the need for the fuel pump to switch off automatically. Ron Quote Link to comment Share on other sites More sharing options...
Sean N Posted February 10, 2015 Share Posted February 10, 2015 Or the other way of doing it is just use an inertia switch to interrupt the feed as many fuel injected cars do. Quote Link to comment Share on other sites More sharing options...
Starfire Posted February 10, 2015 Share Posted February 10, 2015 Live dangerously! Millions of cars were produced without the need for the fuel pump to switch off automatically. Ron Which millions were those, Ron? Mechanical pumps driven off the engine stop when the engine does and most of the rest were fitted with tachometric relays or other safety devices, to the best of my knowledge. There may well have been a transitional period in the 50s or 60s where this was not the case, but the electric fuel pump didn't go mainstream until close to the widespread adoption of EFI. Quote Link to comment Share on other sites More sharing options...
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