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View Full Version : A little help please


Richard Dryden
9th July 2011, 06:37 PM
trying to sort out fueling for my 1.8 cvh currently, assuming the the fuel vaporisation pot needs to be included am i correct in thinking that the 3 pipes on the top should be connected to fuel pump outlet, carburetter intake and fuel tank return.

Many thanks in advance richard

baz-r
9th July 2011, 08:58 PM
yep if your using the std carb
feed from tank > pump > vapour pot then > carb with other pipe returning to tank from pot
i think :rolleyes:

davedew
10th July 2011, 07:09 AM
You don't need it. Gus's car has been running fine for the last six months without it fitted. Just connect pump straight to carb

baz-r
12th July 2011, 06:16 PM
this is an old on going arguement but the way i see it as a automotive engineer is there is a risk of vapor lock and the sierra carb has no return line point unlike some other 2e3 pierburg carbs (vw,vaux) not to mention mech fuelpump design alowing it to folow the cam so i would be fitting it
when webber did conversion kits for the 2e3 thay had a plastic tee with a brass jet fitted in one of the holes (just like a carb jet) this was conected to the return line and you chucked the plastic version of the sierra bit (bmw,vw,vaux)
im sure thay know thair stuff when it comes to fuel systems and a plug for the return would have been easyer to supply
also its handy to have a return pipe if you ever plan on changing to injection or a diffrent setup in the future
for the hassle i would be fitting it

twinturbo
12th July 2011, 06:58 PM
When starting the engine fuel and fuel vapor, from the pump, gets into the reservoir of the vapour separator. Fuelalready in the reservoir will be forced via the riser tube to the carburettor. in this way, the chamber recives, in the first stage of a hot start, fuel which would tend not to vaporise in the float chamber.

Simultaneously, the fuel vapour is returned to the fuel tank via the open ball check valve until a continuous fuel flow occurs. Thereby malfunctions with a hot idling engine and when pulling away are counteracted.

As soon as there is a continuous flow of fuel, the ball check valve closes this assures a good constant flow of fuel by full load throttle. the bypass, in the return connection, allows a continuous, but small quantity of fuel to return to the tank. This prevents a pressure build up to the carburettor when at a standstill with a hot engine. The pressure could otherwise force the float needle valve open and allow the carburettor to flood,which in turn would tend to impede hot starts

TT

Richard Dryden
13th July 2011, 11:53 AM
thankyou for all your help got the chamber mounted there now and putting the fuel lines in, at least i'll have a return for if i swap to a zetec or similar. Many thanks for the help