Are early gas tank vent systems simpler?

[mdbrandy]

I'm looking at my gas tank vent system now (I'm planning on draining and pulling the tank tomorrow), and finding that it looks much simpler than what the fiche shows. Essentially, there's the main filler tube, a vent that comes off the tank and back to the filler tube, and one other vent line that "T's" off the tank vent line, goes up in a loop and back down through the wheel well and just opens there under the car. (Picture attached). The fiche indicate that the "tank-reservoir" 17350-E4600 goes from "no date" to 6/71, which makes me think that I'm missing something . Has someone ripped out much of this system , or are the very early (11/69) systems just that much simpler :classic: .

Thanks.

[Bambikiller240]

I can't answer your question about if it has been modified, but I have never seen a set up like that. But, I've only seen cars that were manufactured from mid- 71 and newer. Thanks for posting the picture though, as I may try to duplicate that set-up to get rid of the vapor recovery tank on my car. The difficulty for me is going to be finding that "T" fitting that connects to the filler tube for the two vent hoses to connect to.

[26th-Z]

No Mark,

You have just discovered one of the fine intricacies of the early series one model. No venting system! The tube just comes down the wheel well as you describe. Do make sure all your hoses and fittings are secure and sealed when you reassemble or you will get gas fumes in the back of the car. Good luck. I found this job a real pain in the arse.

[26th-Z]

Mark,

I found gas tank vent hose boots - both large and small - at Banzai Motorworks in MD. It would be good to replace yours with their Part #'s GF-17 and 18 for about $15. I can't emphasize the need to seal the vent system. Check the T fitting and I would use a hose prep / sealer when I put it back together. I did this procedure in 92 and will do it again with the current project. Installation is a real pain. If you get gasoline fumes in the car after filling the tank, you have a vent leak.

Banzai is at www.zzxdatsun.com 301-420-4200 I have a big list for them.

You demonstrate to me the need to get a digital camera. I'm photographing the old way. I have the parts to send my carbs off to Z Therapy in July. Radiator is restored. Collected most of the parts for the engine bay and I'm focusing on collecting brake parts at the moment. I found a better shop to work on the car and made a major score on industrial shelving - a bunch of it. Work proceeds slowly. I pulled the drive and half shafts Saturday.

[mdbrandy]

Thanks Chris - good to know that the system hasn't been hacked. By large and small boots, do you mean the one that comes through the rear floor (big), and the one that goes down through the wheelwell (small)? I ask only because the wheelwell hose HAS NO BOOT AT ALL! I intend to replace essentially every piece of rubber on this car that I can obtain, so thanks for the source:classic: . I've been on Banzai's site, but hadn't looked for these specifically yet.

And I LOVE my digital camera. I currently have 373 pics of the car and it's systems as I've taken it apart. It'll be a lifesaver when I put it back together, I'm sure! I also use it for kids baseball games, concerts, birthdays, etc. I used the zoom to take a nice picture of a big blue heron on our pond the other day. I bought a nice one (Nikon coolpix 4500), but it gives me full manual control when I want it, which many of the less expensive cameras do not.

Bambi - zparts has a small page about vapor leaks, and seems to be into vent parts. Might ask there for the t-tube.

http://zparts.com/zptech/articles/gasfumes/gasfumetech1.html

Thanks all.

[26th-Z]

My parts fiche shows the fuel recovery system and is no help at all. If memory serves me, the gas tank vent hoses come up through the floor and then turn toward the filler inside the car. Your picture shows the T valve (Nissan part 17227-E4100) and the hoses, but not where they pass through the floor. There is a rubber grommet for the opening and the boot fits over the opening, sealing the hose on the inside of the car. I'm going to have to look at mine and take a picture. The hose just doesn't simply pass inside the car through a grommet. It is sealed with the boot.

[EScanlon]

From what I recall and what I've researchec on the Fiche, ALL the 240 Z cars had Vapor Recover Tanks. That yours does NOT have one shows that it has been removed and that arrangement you have is someone's idea of how to bypass the tank and not replace / cap hoses.

The EARLY VPRT were plastic, of a type similar to the Windshield Washer Fluid bottle. They got brittle with age and the fumes and would crack and literally crumble into dust, releasing fumes into the passenger compartment. Later ones were metal and depending on whether you are a Series I or II differed in shape.

FWIW

Enrique

[mdbrandy]

Originally posted by EScanlon

From what I recall and what I've researchec on the Fiche, ALL the 240 Z cars had Vapor Recover Tanks. That yours does NOT have one shows that it has been removed and that arrangement you have is someone's idea of how to bypass the tank and not replace / cap hoses.

OK. I have the tank out now. The difficulty I see with the assertion that all 240's had vapor recovery systems is that there are NO OTHER VAPOR CONNECTIONS TO THE TANK except for the one main one back to the filler tube. So. Either someone hacked the vapor system AND replaced the gas tank, or this car never had the multiple hose system that the fiche shows. There are two hose connections shown on the fiche that this tank never had. The parts fiche lists three different tank assemblies, the first of which is 17201-E4100. The second tank listed, under description, says "ASSY-TANK FUEL FOR EVAPO", which indicates to me that it may be for a vapor system, while the E4100 tank is not. Certainly not conclusive, but from what I saw under my car, if this is not the original fuel tank, it was replaced fairly early in the car's life.

So, any thoughts on what this new evidence means that are different than my interpretation?

Thanks.

[mdbrandy]

Oops. I forgot to attach the picture.

[26th-Z]

Thanks for the part # references. From the sound of it, I'll be looking for a vent tank. Scotty-the-Datsunmeister concurs that early tanks were plastic and that they broke. I won't get my gas tank out for another month, but I'll check my vent situation and let you know. I have only one vent hose through the rear floor just behind the tail light - where that boot goes. Glad to see you dealt with the straps.

[Bambikiller240]

While I have no definitive information, I do seem to remember someone (perhaps Carl Beck, owner of ZHome.com) stating that the very first Z's to arrive had no evaporative system. That it was added quite early in the 1070 model year.

I suggest contacting Mr Back on the ZHome mail list and asking for clarification.

Your tank certainly look just like the later ones except for the missing vent near the inlet/outlet fittings, and the vent at the driver-side rear of the tank. I doubt that it has been hacked.

[26th-Z]

Further,

Compare the part numbers of the gas tank to the corresponding vent tank numbers. The E4100 gas tank is listed up to 7/73 as is the second listing E4600 with evapo. The original vent tank, 17350-E4600 lists only to 8/71 and then E4601 continues to 7/73. E4600 doesn't list with Nissan but E4601 does; $127.29 if it is still available.