I have a 73 240-Z. Restoration getting out of hand, but I shall see it through. We dropped the gas tank and have the interior panels out. I am wondering what items can be eliminated completely or closed off with plugs, etc. There is a tank in the cargo area on the right side that is probably useless...maybe some of the gas tank fittings as well. I am running earlier SU carbs but have a new set of Weber downdraft carbs to install if they are a better bet. All comments appreciated...Ryals in north Georgia

Why do you think the expansion tank is useless? Be careful about plugging up vent holes. The mechanical fuel pump won't pull well on a vacuum.

As for the SU vs downdraft, most of the people who installed the Weber downdraft carburetors did so to work around the issues with the 73/74 flat top carburetors, or they didn't understand how the round top SUs work. No advantage for the Webers over round top SUs in good shape.

Seems like there was a recent thread about removing the expansion tank and all but one of the vents on the tank. Seems like @Carl Beck gave some direction on doing this and still keep the tank properly vented. The vent on the tank that was kept was also turned 180 degrees to eliminate the need for the horseshoe bend in the vent line. Hopefully Carl will jump in here and either enlighten the thread or tell me I just dreamed this up!

Thanks to both of you for chiming in. I am a Triumph guy venturing in to new territory with this Z project. EPA BS killed British Leyland as things got so complicated fuel system-wise. I am very familiar with SU's from my TR world, I bought a bunch of Z parts and a new set of Webers was included in the lot. I have round tops to fall back on...just wanted to see what the downdrafts would do. The tank issues with respect to venting are the big thing for me. Seems like the time to eliminate what I can as no EPA numb-nut is going to be knocking at my door asking to inspect the car. And if that expansion tank can be eliminated, I will put it on the shelf with the flat tops...! I am really enjoying working on the 240...a little tired of the same old British rut. Although I will never sell my TR4...!

Hi Tirnipgreen:  

The Gasoline Vapor Recovery System (GVRS) was required for cars manufactured in 1969 and early 70 only in California. Because California was a very large Sports Car Market most of the cars sent to North America get it as standard equipment. By late 1970 it was added to the Federal EPA Emissions Standards/Regulations. 

 

Yes, you can eliminate the entire system fairly easily. Here is a summary of much discussion.   This shows how to make the 180 degree turn on the one remaining Vent Line - although another person just had that vent tube re-positioned when the gas tank was out. Either way works..

 

http://zhome.com/Racing/FuelTankVaporLineMod/FuelTankVaporMod.htm

 

hope that helps, BTW - if you have the SU's I'd stick with them. If you go Webers - go triple side drafts.

 

Carl B.

Edited March 26, 20195 yr by Carl Beck

Carl...Thanks...! I am going to eliminate the vents all together when I have a shop clean the tank. I was thinking of having the outside waterjet blasted and powdercoated. Any thoughts...? Thanks again...Ryals 1973 240-Z 115 Blue / White interior

3 hours ago, Tirnipgreen said:

Carl...Thanks...! I am going to eliminate the vents all together when I have a shop clean the tank. I was thinking of having the outside waterjet blasted and powdercoated. Any thoughts...? Thanks again...Ryals 1973 240-Z 115 Blue / White interior

Bad idea to delete all the vents

I would never delete all of the vents. I will leave the big one that is connected to the filler neck. But the two small ones go nowhere with the elimination of the evap tank...which is EPA nonsense. If anyone ever wanted to put it all back, they will have the parts to do so...along with the flat top carbs.

I agree with Patcon, you need some sort of vent, or you get vapor lock = no fuel. 

Even with just one vent line tagged to the filler tube bung, it is the gas cap that does the venting. Check that as well.

 

 

 

In addition to the filler line vent pictured in Carl's post you should leave the top vent on the tank which T's into the fill line vent in Carl's picture. If you're going to have someone do the tank vent deletes for you, have them reverse the direction of the top vent like @z8987 did that then feeds to the vent line shown in Carl's link @ zhome.com. Here's a picture of @z8987 's tank with the single vent - top / rear of tank;

 

Edited March 27, 20195 yr by w3wilkes

6 hours ago, Tirnipgreen said:

Carl...Thanks...! I am going to eliminate the vents all together when I have a shop clean the tank. I was thinking of having the outside waterjet blasted and powdercoated. Any thoughts...? Thanks again...Ryals 1973 240-Z 115 Blue / White interior

I've never had anything waterjet blasted... so I don't know if that is a good thing or not.  A good powder coat application is hard to beat.  

Thanks for the pic, Wilkes. I like the reverse elbow mod.