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Checking tank ventilation
- Thread starter oport
- Start date
robin collis
Active Member
I have an early P6B (1971) that used to suffer from Vapourisation very badly, despite fitting an electric pump (Facet) but... it would occur after only 2-3 miles driv9ign. and took longer than 5-mins resting to cure; often over 1 hour to allow all of the engine bay to cool.. Finallyraced to lack of coolant circulating through the Carburettor tower. Check that water is flowing from the tower back to the radiator, via the thin (2cm.) hose to just below the rad. cap.
Your problem does not seem to be Vapourisation, and is not like mine which was most definitely vapourisation. but only ever happened on English summer days, never in winter.
Are you getting a full flow of fuel in normal conditions? Could it be muck in he fuel tank partially blocking the fuel line? Does changing to reserve make any difference? In take is lower in the tank and more susceptible to blocking.
I remember a partly blocked fuel filter causing similar problems to yours.
Your problem does not seem to be Vapourisation, and is not like mine which was most definitely vapourisation. but only ever happened on English summer days, never in winter.
Are you getting a full flow of fuel in normal conditions? Could it be muck in he fuel tank partially blocking the fuel line? Does changing to reserve make any difference? In take is lower in the tank and more susceptible to blocking.
I remember a partly blocked fuel filter causing similar problems to yours.
mikecoombs
Active Member
The fuel return line doesn't actually make it back to the tank. the line runs with the two feed lines and joins into one of them under the tank just prior to connection.
the fuel tanks for V8 came in two types, one with a single vent fitting and one with two. One is for non emission cars with no vent tank at the rear of the main and the other for the emission cars. I forget which is which but I recall soldering a plate over one hole for my P6B which is an emissions car. This makes sense as the vapour tube goes up into the passenger (RHD cars) C pillar then back down and around the (two) tanks a few times and into the vapour tank. it then exits the vapour tank goes up the drivers side c pillar and runs along the inside corner of the the roof then through a fitting in the top drivers side corner of the roof which brings it out in the forward roof drain under the SS capping. finally running along the inner/outer guard join then turning left into the drivers side charcoal canister. The Canisters (one each side) are seperately connected to the inlet elbows. The Second canister is fed from the carburetter float vents. Note on cars with separate float bowls the vent pipes exit on the opposite side of the bowl (facing each other) to cars with simple drain vents. There is a pipe between them and a T intersection to take the gas to the cannister which is connected to the second carb elbow. The Cannisters also have a largish open fitting near the bottom which is there for purging the charcoal and left open.
the fuel tanks for V8 came in two types, one with a single vent fitting and one with two. One is for non emission cars with no vent tank at the rear of the main and the other for the emission cars. I forget which is which but I recall soldering a plate over one hole for my P6B which is an emissions car. This makes sense as the vapour tube goes up into the passenger (RHD cars) C pillar then back down and around the (two) tanks a few times and into the vapour tank. it then exits the vapour tank goes up the drivers side c pillar and runs along the inside corner of the the roof then through a fitting in the top drivers side corner of the roof which brings it out in the forward roof drain under the SS capping. finally running along the inner/outer guard join then turning left into the drivers side charcoal canister. The Canisters (one each side) are seperately connected to the inlet elbows. The Second canister is fed from the carburetter float vents. Note on cars with separate float bowls the vent pipes exit on the opposite side of the bowl (facing each other) to cars with simple drain vents. There is a pipe between them and a T intersection to take the gas to the cannister which is connected to the second carb elbow. The Cannisters also have a largish open fitting near the bottom which is there for purging the charcoal and left open.