Another Fuel tank thread - 71 Demon
I've run into an interesting issue on my 71 Demon 340. This car was purchased new in the Cleveland Ohio area - I've owned it since 1984 and is basically an all stock and original car. So it is not a California emissions car. I bought a new tank for it before I crawled under there and found the old tank has the 4 vent lines coming out of the side. Well of course I had ordered the wrong one as the new tank has the single vent line in the front by the sending unit. Not to worry, I'll just get the correct 4-vent tank and pop it in and life will be good. NOT!!! (Note that I got both tanks from AMD.)
I learned that the 4-vent tank and the 1-vent tank are called an 11D and 11E respectively. It seems that sometime in the middle of the 71 Model year, there was a change made to the location of the filler pipe hole. The later tanks moved the fill hole rearward by 1/4"-1/2". At the time the fill hole was moved rearward, the vent system was supposedly changed from a 4-vent to the single vent. Hence the sequence change from calling one an 11D (4-vent, forward fill) and 11E (1-vent, rearward fill). So the 11E should have the more rearward fill pipe. I measured the 2 tanks from AMD and indeed the 11E filler pipe hole is more rearward by 1/4"-1/2" (hard to measure perfectly). This explains why you can order a 70-71 tank or a 71-76 tank...they apparently verlapped sometime in the 71 model year.
My car is a late-built 71 (ordered in March, delivered in May 1971). And of course nothing is easy....my car has the 4-vent tank that uses the standpipe in the trunk for the 4 vent lines to connect to but uses the later rearward location of the fill pipe hole! So I apparently have an 11D vent setup with an 11E fill pipe hole location. Well when you try to put the fill pipe in with the 11D 4-vent tank, you can get it in and attach it to the quarter panel BUT when you go to install the trunk floor seal....nope, it's too far forward in the trunk. And there's no way to stretch that thick rubber to attach it to the trunk opening. And if you did, I'm certain the tank filler tube rubber gasket would be compromised and that $5/gallon fuel would be splashing out! Also, I don't want that stress on the pipe to damage the quarter panel tugging on those 3 little screws attaching the filler pipe!
Anybody else ever run into this on a Duster or Demon? I'm thinking to use the later 1-vent line tank so the filler pipe/trunk floor gasket line up and just run that single vent line to the standpipe. I would just need to know which of the 4 little tubes going into the standpipe was the lowest so that any fuel fuel going into it could then go back out of the standpipe. Anybody know which one of the 4 tubes it might be?
Here's a generic sketch for the 4-vent system from I think a 73 service manual - I couldn't find a manual for a 71. Those 4 lines actually come out just forward of the filler pipe.
Someone out there knows these fuel tank systems better than me and can maybe shed some light on this!!
I've run into an interesting issue on my 71 Demon 340. This car was purchased new in the Cleveland Ohio area - I've owned it since 1984 and is basically an all stock and original car. So it is not a California emissions car. I bought a new tank for it before I crawled under there and found the old tank has the 4 vent lines coming out of the side. Well of course I had ordered the wrong one as the new tank has the single vent line in the front by the sending unit. Not to worry, I'll just get the correct 4-vent tank and pop it in and life will be good. NOT!!! (Note that I got both tanks from AMD.)
I learned that the 4-vent tank and the 1-vent tank are called an 11D and 11E respectively. It seems that sometime in the middle of the 71 Model year, there was a change made to the location of the filler pipe hole. The later tanks moved the fill hole rearward by 1/4"-1/2". At the time the fill hole was moved rearward, the vent system was supposedly changed from a 4-vent to the single vent. Hence the sequence change from calling one an 11D (4-vent, forward fill) and 11E (1-vent, rearward fill). So the 11E should have the more rearward fill pipe. I measured the 2 tanks from AMD and indeed the 11E filler pipe hole is more rearward by 1/4"-1/2" (hard to measure perfectly). This explains why you can order a 70-71 tank or a 71-76 tank...they apparently verlapped sometime in the 71 model year.
My car is a late-built 71 (ordered in March, delivered in May 1971). And of course nothing is easy....my car has the 4-vent tank that uses the standpipe in the trunk for the 4 vent lines to connect to but uses the later rearward location of the fill pipe hole! So I apparently have an 11D vent setup with an 11E fill pipe hole location. Well when you try to put the fill pipe in with the 11D 4-vent tank, you can get it in and attach it to the quarter panel BUT when you go to install the trunk floor seal....nope, it's too far forward in the trunk. And there's no way to stretch that thick rubber to attach it to the trunk opening. And if you did, I'm certain the tank filler tube rubber gasket would be compromised and that $5/gallon fuel would be splashing out! Also, I don't want that stress on the pipe to damage the quarter panel tugging on those 3 little screws attaching the filler pipe!
Anybody else ever run into this on a Duster or Demon? I'm thinking to use the later 1-vent line tank so the filler pipe/trunk floor gasket line up and just run that single vent line to the standpipe. I would just need to know which of the 4 little tubes going into the standpipe was the lowest so that any fuel fuel going into it could then go back out of the standpipe. Anybody know which one of the 4 tubes it might be?
Here's a generic sketch for the 4-vent system from I think a 73 service manual - I couldn't find a manual for a 71. Those 4 lines actually come out just forward of the filler pipe.
Someone out there knows these fuel tank systems better than me and can maybe shed some light on this!!
