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MG MGB Technical - fuel pump
hi 79 mgb. have been using an acdelco fuel pump(ep12s), but it is too powerful and will flood the carb if not careful. otherwise it works good. i want to install an old "walbro" pump (wep12)but the instructions read: "won't perform properly if used on a vehicle with a vapor return line" i really don't know what this is or if my mgb has one. if my haynes manual describes it, it calls it by another name. also, will todays gasoline with added ethanol affect this pump? thanks a lot for any help. john |
john |
p.s. the mgb has a standard z-s carb with most of the polution stuff and the automatic choke removed. john |
john |
Unfortunately saying 'most' of the pollution stuff has been removed doesn't help. A 79 did originally have a couple of 'vapour return lines', but I don't see how these would affect any fuel pump, they only do what the original vented fuel filler cap and float chamber vents on earlier models did and that is allow pressure equalisation with temperature changes and fuel usage. |
Paul Hunt 2 |
The pump is designed to work on a 'closed' system and not one where continuous pumping is required as a result of either a gas return line to the tank or evaporation lines. A closed system goes from the tank to the carbs and has no other lines. I don't know why but I guess it has to do with back pressure. |
Mike MaGee |
Why not put an original SU on? It is going to work right and will usually last 20-25 years or more Ralph |
Ralph |
hello again the polution stuff removed is: air pump, the manifold of four pipes to the passenger side of the block sealed with 7/16" bolts, the gulp valve off and sealed. thats all i did, i think, it's all i remember. the canister is still there, but the separation tank is not there, at least i don't think there is one. there was/is a separation tank ,un- connected, in the trunk of the car ever since i bought it. i hope this helps you all to decide if this bellows type pump will work with the above mentioned caveat about a vapor return. yes, i could simply install it to see if it works, but i'm too old to to want to put it back the way it was if doesn't work. i could also get an su pump, but i used this type of pump on an mg midget some years and i liked it. it had twin hs carbs. again, thanks for any insight. john |
john |
1980's subaru pump, locate in engine comartment. Works a treat. see archives ad nausium. |
Peter |
I used an SU unit which had the old points system changed to an electronic c/b. The unit has the same appearance, and everything attaches and fits just as the original. cheers gary :>{D 79 mgb |
gary n. hansen |
This thread was discussed between 31/10/2005 and 06/11/2005
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