72 Nova Fuel line routing [Archive] - Chevy Nova Forum

: 72 Nova Fuel line routing


RStephen
8th-July-2010, 01:16 AM
I have a 72 and am replacing my stock small fuel lines and sending unit to larger diameter line/sending unit. The original sending unit had one small fuel line coming out and the replacement with larger fuel line has an extra smaller line coming out which i think would be a return line???
Also... Located behind the back passenger seat is a canister that has 4 lines coming from it. Does anyone have a diagram of where these lines go and if they are all necessary?

veno
8th-July-2010, 09:30 AM
the small line is a vent... that hooks to the canister

RStephen
8th-July-2010, 09:42 AM
The canister has 4 lines. The fuel tank has 3 lines. The new sending unit has one small line as well as the fuel pick up. That's 9 lines. I know where the fuel pick up line goes :yes: but the other 8 :no:. Anyone got a assembly guide for this? or... Anyone have a diagram of a good working system that can steer me in the direction of what goes where?

sbc1320
8th-July-2010, 09:49 AM
The other lines hook up to the gas tank and I'm guessing to the evap. cannister in the engine compartment. Sorry, no diagram. Years back I bought a new tank for the my 71 and I sumped it and ran a 1/2" aluminum line to the front. My orginal was a 5/16" (factory 307) line and sending unit. I remember there were something like 4 outlets on the corners of the old and the new tank. There were something like 2 on each side and connected to the EEC or whatever you call that piece behind the seat and inside the trunk. I did hook all those back up, but up front I did away with the evap. cannister and just left the metal vent line unplugged. Hope this helps anyways.

waverous
8th-July-2010, 10:39 AM
I have a 72 and am replacing my stock small fuel lines and sending unit to larger diameter line/sending unit. The original sending unit had one small fuel line coming out and the replacement with larger fuel line has an extra smaller line coming out which i think would be a return line???
Also... Located behind the back passenger seat is a canister that has 4 lines coming from it. Does anyone have a diagram of where these lines go and if they are all necessary?
Good question - I would like to use the vent line as a return line as well. I have a new sending unit and the vent is unobstructed (as far as I could tell blowing through it before I mounted it) so why not? I'm not running an EFI setup but I am using a HVLP pump and regulating pressure to my dual quad setup and I would like to drain back into the tank via the vent tube

veno
8th-July-2010, 10:43 AM
should not be a problem.. but be sure to use a vented gas cap...

walkerjay
8th-July-2010, 05:05 PM
Not sure these are helpful but here are a couple of my "before" pics. I may have some more. They also have all the EEC routing in the assembly manual so I can snap a pic of that next time I make it to the garage. It clearly shows where all that stuff goes.

I have a 71 and decided to buy a 70 tank and eliminate all the EEC stuff.

http://i79.photobucket.com/albums/j151/walkerjay/nova%20archive%20photos/fueltankbody.jpg

http://i79.photobucket.com/albums/j151/walkerjay/nova%20archive%20photos/fueltank1.jpg

http://i79.photobucket.com/albums/j151/walkerjay/nova%20archive%20photos/fueltanktop.jpg

http://i79.photobucket.com/albums/j151/walkerjay/nova%20archive%20photos/fueltankold.jpg

RStephen
8th-July-2010, 06:06 PM
ok... this helps a lot. One question... the line on the far left, was it going to the tank driver side corner or was it the one going up to engine compartment to charcoal canister?
Thanks...

walkerjay
10th-July-2010, 06:16 PM
I wish I could tell you for sure but I don't recall. I do know that the vent line to the engine compartment canister was a smaller diameter than any of the lines in the pics. Seems I may have removed that one first.

The loose line in the bottom pic does not look like the same line in the second pic because the second pic line clearly has a sharp bend to it. The loose line in the bottom pic is straight before it gets to the rubber hose and sure looks like it goes to that empty line on the eec trunk unit.

I will get a pic of the assembly manual for you. It shows where everything goes.

walkerjay
11th-July-2010, 09:39 AM
Fuel system pics from 1971 assembly manual. Hope I'm not causing trouble but I see nothing in the manual about unauthorized reproduction or copyright infringement...

Firstly....here is my setup and I too am wondering where the small line with the gray cap should go. I have a GM46B 1970 style tank with vented cap. thx.

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuellinenew.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel1.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel2.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel3.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel5.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel9.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel11.jpg

the rest are here....

http://s79.photobucket.com/albums/j151/walkerjay/Fuel%20system/

RStephen
11th-July-2010, 05:12 PM
Looks like we have the same sending unit. I talked with a friend of mine that has a BBC in his Nova. We were discussing the fuel lines and he brought up a very good valid point. The small line is for a fuel return. He told me that Chevy decided (later on) for their high performance cars that a return line was needed to keep the fuel cool up to the carb. He said they used two options. 1. They had some fuel pumps that had the return on them and 2. they made a fuel filter that mounted close to the carb that had a return line on it. He also mentioned to me and suggested that I continue to use the ECC as a tank vent. He said that with my big block and a vented gas cap I would leave fuel snail trails behind on hard launches. This conversation has convinced me into running a second line up front to utilize this sending unit return line. ARGGG... back under the car! I'll post pictures later. Thanks for the pages they will be a big help.

walkerjay
12th-July-2010, 01:31 AM
sounds like a good way to go.

GM does things for a reason and it's usually a good one. If I could do mine over, there's a good chance I may have left it alone and hooked up the eec again....mainly to keep me from having to plug the hole in the trunk, and also respect for the vehicle the way it was made. It's just one more thing on my to do list. really 6 of 1, half dozen the other.

back under the car??????where else would you rather be?

bullette
12th-July-2010, 03:08 AM
Veno - Walkerjay - Anybody,

I have a 68, single supply, no return lines. I am going to change the tank and the lines soon. Is there any advantage (performance or otherwise) to changing to a multi-line system? I'd rather buy once, install once.

walkerjay
12th-July-2010, 08:54 AM
Not sure...a single line system designed that way from the factory seems the simplest way to go. Sounds like your system may use a vented cap...? And simple is always a good approach in my opinion. Unless of course your adding power, fuel injection, elec fuel pump and actually NEED the return lines. The only thing i can think of is to upgrade to a 3/8" line if yours is smaller.

FYI: Wherever you get your tank, do your best to get a compatible gas cap at the same time. Perhaps from the same manufacturer. That way you don't have to scurry around later to try to find the proper one. Then again, you always have your original to fall back on.

bullette
12th-July-2010, 09:02 AM
Thanks Jay. Back to plan "A".

RStephen
13th-July-2010, 10:37 AM
Bullett... To answer your question I noticed that you are in Texas running a BBC. I live in Oklahoma and also see my share of tripple digit summer days. My last BBC was in a 68 camaro. I did have occasional fuel problems in summer months with an occasional and very inconvenient vapor lock issue. BB cars have a lot less clearance between the fuel line running up the passenger sub frame rail and the motor/exhaust. The reason I decided to run two lines with my 496 in my Nova is to prevent potential vapor lock by recirculating the fuel so it wouldn't turn into vapor on me and... I also like the performance aspect of having cool fuel to my intake. Hope this helps...

sYcNova
26th-January-2012, 09:35 PM
Fuel system pics from 1971 assembly manual. Hope I'm not causing trouble but I see nothing in the manual about unauthorized reproduction or copyright infringement...

Firstly....here is my setup and I too am wondering where the small line with the gray cap should go. I have a GM46B 1970 style tank with vented cap. thx.

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuellinenew.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel1.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel2.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel3.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel5.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel9.jpg

http://i79.photobucket.com/albums/j151/walkerjay/Fuel%20system/fuel11.jpg

the rest are here....

http://s79.photobucket.com/albums/j151/walkerjay/Fuel%20system/

Huge help in my current need, referred from another post.

Thanks Jay.