MGB & GT Forum

I have two gt's, one '70' one '71. the '70's tank is vented, the '71's tank is NOT vented. I also have a '76 roadster whose tank IS vented and I am replacing the tank. Here are the questions that come up:
1. Why would the '71 GT not be vented?
2. Why would the two GTs be different than the '76 in that the '76 has a filler that is straight up, not angled as in the earlier tanks. ALSO the filler tube (which is not available) is a straight tube with a 90 degree filler hose while the other two are angled with a straight, and much shorter filler hose? The tank that arrived for the '76 has an angled tube on top requiring an angled filler tube and straight hose as the two GT's have. WHat gives...I am in a bit of trouble because the filler tube is not available and the one I have on the car is not compatible with the new tank. Clear? I hope so, what say you?

Just to be clear... by "vented"...you mean there is a fitting aft of the filler neck on the tank which is connected to a circulation tank mounted on inner RH rear wing?

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"It is a mistake to try to look too far ahead. The chain of destiny can only be grasped one link at a time."
Sir Winston Churchill
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"It all starts in your mind's eye, then it goes to your heart
and finally to your very soul."
G.S.George PHD

Exactly. the '71 does not even have the hole for the fitting in the "trunk".

The '71 has a vented cap.
I don't know when the changes occurred. But with the evap system and charcoal canister, the vented tank is used. No reason not to as it keeps gas fumes contained.
Also don't know if either of your present tanks have been changed from original. Someone here will surely know the changeover dates.

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"It is a mistake to try to look too far ahead. The chain of destiny can only be grasped one link at a time."
Sir Winston Churchill
---------------------------------------------------------------
"It all starts in your mind's eye, then it goes to your heart
and finally to your very soul."
G.S.George PHD

70 also has the canister in the trunk, 69 doesn't that I have seen so far.

Two issues in one post: the venting and the filler tube. Venting started in 1970, I had it on a march 1972 car, filler tube was also different. BUT with the RB cars yet another tube came in. The 1976 GT is a RB CAR!

OK but the '76 I have is a RD and the '71 is Not Vented, not even a hole in the floor for the fitting

Well the introduction of venting the gasoline tank, the addition of the overflow tank linked to the carbon canister (later even a valve was added for closing the canister with the engine off) were not all done simultaneously. Some measures for California predated those for other export markets, until at the very end only two main streams for the RB cars emerged: SU's and no extra's for Europe and Strombergs with all the emisson controls and catalysator for the USA/CAnada markets. CB cars like yours and mine had different arrangements fitted between 1970 and 1973..

Another issue is the difference between production dates and model years: the new model year started in august, so modelyear 1971 could've been produced in fall 1970

The main thing for you is finding the right filler neck. When I removed all emission control extra's on my CB car and wanted to mount a standard filler cap with a lock, the filler pipe could still be bought new, nowadays you have to find a second hand one. Andy Jennings in the UK supplies some 2hand parts via Web ordering and postage across the globe. Why not try it? The alternative is finding a scrap yard yourself with B's that were not sold for restoration (must be rare in the States by now)

UK ebay is a good place to find that steel filler neck & hose for a late car. It will also be the type that uses a vented filler cap that can be locking. I replaced the tank in my US 78B with a UK Heritage tank. It is non vented, I found the filler neck with out the internal "flap valve" on UK ebay and then fitted a locking vented cap. The car is in winter storage at the moment so I cant view it immediately BUT it seems to my memory that the steel fill pipe was straight the hose had a bend and matched up with the slightly angled intake to tank. If that helps..

Hi Joe,

Could it be that your '71 is not actually a '71? Perhaps it was titled later, in the year it was sold? What is the VIN?

On the fuel filler neck, I should still have this one in the barn if it helps out.

MGB Fuel Filler Neck 1970-75

Cheers,

Rick

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If I could get all the money back I ever spent on cars. . . I'd spend it on cars. - Nick Mason (Pink Floyd)

There was nowhere to go but everywhere, so just keep on rolling under the stars. - Jack Kerouac

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The journey is the destination.

the moss catalog says to use an earlier setup since they are the only ones available and they fit well....I will end up doing that I think....looking on ebay for used parts now

It is a '71 and there is not clearance in the deck for the vent fitting.