sdyck

Fuel Tank Vent Lines

31 posts in this topic

I do have a fuel smell in the cabin of my car: I expected to take off the panels at the back and find a bunch of rotten hoses. But they look pretty good as you can see from the attached pictures. The hoses are pretty hard, are the cloth hoses very pliable when new? There is one long line that runs along the back panel that goes through the floor that should have a grommet at the floor but doesn't, not pictured. I might try just changing this and renewing the grommet to see how it does.

Are there any of the lines that cause particular problems?post-29415-0-01387300-1416089791_thumb.jpost-29415-0-06147600-1416089841_thumb.j

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Check your fuel/air/vapor separator for any cracks or defects in the braze joints.  Mine had a crack where one of the nipples was brazed on.

 

Even though you say your hoses look good, they shouldn't be hard.  If those are the original hoses, one of them could be cracked or split.  I'd replace all of them with new.

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I can't seem to find any old threads, "404 Not Found", keeps showing up this morning but there's alot of info on that.  I cleaned my tank and replaced all those hoses a few months ago.  Mine were original and hard as a rock, all cracked on both ends.  There's only 1 you can get to easily, 1/2" that comes out the top driver's side of the tank.  The others are a PITA but doable with the tank out.  here's the only one I can find, http://www.classiczcars.com/topic/24181-rating-the-factory-240z-fuel-vent-hoses/

 

I think replacing the hatch gasket would be my 1st attempt at getting the smell out of the cabin. 

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Thanks guys. Siteunseen I have both an exhaust smell and fuel smell. I'm going to redo all the rear light gaskets and hatch seals as well as make sure all the holes in the hatch floor are well sealed for the exhaust issue.

For the gas smell I've read every post I can find. I see most of the hoses are nla and many have crazy bends. I did find one post that listed replacements from McMasterCarr but it was old and most of those are Nla too. McMaster has some great alternatives with low bend radiuses.

I guess I'll get stuck in on taking it all apart and checking the hoses before I order anything.

My car is from Arizona with pretty low on rust so I'm expecting the gas tank to be pretty clean. If I empty it and drop it off the car for a while is there something I should fog it with t keep the rust at bay over the winter?

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Today the best thing to do with an old gas tank - is buy or rent a good inspection camera and look inside - then decide what you need to do. There are lots of different processes to be considered  - depending on what you can see. 

 

I think the hose that is the more difficult to deal with - is the one that come off the top of the tank - and required a tight 180 degree bend. Various ways of accomplishing that.. several documented here on the forum.

 

Personally - on the 240Z's I drive fairly often - I just eliminated the vapor recovery lines all together. But even so you still have to deal with proper venting of the tank, so it can be filled. Which means you still have that long line with the 180 degree bend to deal with.

 

good luck,

Carl B. 

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What is this fitting called? It's about 3/4" and joins the main fuel filler hose to the thick line that goes to the vapour tank. It's got a nice big crack in it.

I don't see it listed at the z store. Is it a standard item I could pick up at an auto parts store

Thanks.

post-29415-0-76198600-1416167626_thumb.j

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I don't know where you'd find that coupling but when I did mine I used brass "PEX" fittings.  Any plumbing supply or hardware store should have them.  https://www.google.com/webhp?sourceid=chrome-instant&rlz=1C1BOFA_enUS494US494&ion=1&espv=2&ie=UTF-8#q=3%2F4%22%20pex%20coupling

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That looks to be the JOINT-TUBE BREATHER  17227-E4100 or 17227-E4600 per the online catalog up to 7103.  For 7104 and after it is 17227-E4101 or 17227-E4601.  The catalog shows this as a "T" fitting, mine is also a straight fitting.  Unfortunately I can't do a paste from IE to get the catalog link to you.  The "T" fitting might be the 4100/4101 and a straight fitting might be 4600/4601 or vice-versa.  This is probably a Nissan-only part, see if your dealer can help.

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Thanks, It looks like I'll need to come up with an alternative. The brass fitting looks like it would work.

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Here's some Sta-Bil fogging oil for winterizing engines, it should work for your tank.  I've never used it but it got 5 stars from amazon.com

 

https://www.google.com/search?q=STA-BIL%2FFogging+oil&rlz=1C1BOFA_enUS494US494&oq=STA-BIL%2FFogging+oil&aqs=chrome..69i57j69i58j69i60j69i61l2&sourceid=chrome&es_sm=93&ie=UTF-8

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 Considering eliminating the vent tank. According to a search there are supposed to be instructions at this link;
http://www.classiczc...light=fuel vent
 

But the link doesn't work. Does anyone have a better link?

 

Thanks

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Just did this due to the issue of a full tank and a left turn would release gas fumes into the interior. While I had the tank down, had it boiled out and sealed at a radiator shop that also did the Renuzit (?) tank treatment. When the guy looked at the tank, he said it didn't need the full treatment for around $300+ (which I would gladly have paid) but instead boiled it out, coated the inside and painted the outside. Still paid about $200 but should be good for another 20+ years. Also replaced all vent lines and the filler tube (MSA and aftermarket generic fuel lines). Still able to get about 2 of the lines from MSA but got creative with the bends needed for the unavailables. Used a spring inserted inside generic fuel line for the big bend to prevent collapse of the line. Also read you can use the PEX/plumbing brass 90deg elbow to make the sharp corner. Result is a full tank, left turn and no gas smell inside the cabin. Exhaust smell would def benefit from a redo and seal of all tail/hatch gaskets. I'd already done that part in addition to adding an extension to the exhaust and seal of the antenna drain tube grommet.

You can get away reasonably cheap except for the tank boilout/treatment. But I look at it this way. I'll prob never have to d*** with this again in my lifetime.

sorry for the long post but go for it.

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Thanks Bart, will probably go the same route. Considering just eliminating the vent tank and lines and capping things off. Always worried this will lead to other issues, so will probably do the whole thing.

Steve

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Use Goodyear E-Z coils for the bends:

 

http://www.veyance.com/productsDetail.aspx?id=17254

 

You can get larger size fuel hoses from a tractor supply house.  You can also buy some really nice marine-grade hose from a marine supply store.  If it's USCG marine-rated, then it's fuel resistant.  DON'T use heater hose!

 

I think your decision to keep the little tank is probably a good one.  I think it courts problems to buck the design.

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post-24724-14150829135495_thumb.jpg
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I bought all my hose at an O'Reilly's Auto Parts store.  They had all the way up to 5/8" on hand.  Hoses and clamps were around $60, quart of Red Kote tank liner was $30.  I have hundreds of PEX fittings, so $100 and a week of time.  If I can find some of the pics.

Don't forget a Fram G2, $3 bucks, coming out of the tank's supply side.  That picture isn't my 240s G2, thats a 280 with the G3.

Nissan still has the fuel sending unit, $50.  The wires going to it are what they call "nail head" connections and they are a PAIN.  When you get them on slather them up with liquid electric tape.

 

Picture: I used a 1/2" pex 90 degree for the small vent line above the sending unit.

You'll need two 3/4" pex 90s for the 180 turn on the top of the tank, it's the 5/8" hose connection.  I'll find a picture of that somewhere, I know it's on my computer!

That box has the Nissan part number for the sending unit.  You'll also need an O ring, p/n 17342-18000

Gotta go, more when I get time.

 

Cliff

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Fastwoman, definitely looked at the E-Z coils. I felt since they're only vent lines (no liquid to worry about flow restriction) and the bend was so extreme, I'd rather worry about the inside diameter collapse. Plus the stainless springs were cheaper. :D 

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Not cheaper than my EZ Coil!  The auto parts guy had a couple of samples, didn't figure they could sell any, and said, "Here, try this doodad.  It might work."  And it worked great.  Seriously, I have no idea what they cost.  They look a bit pricey.

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Cool, love the pics. Took a look for the EZ coil. Canadian tire sells them for $7.00 a pop up here might give them a try

FastWoman, did you use the EZ coil so the 180 degree bends? and no issues?

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Her 280 doesn't have all that mess, fuel injected.  ;)

 

Finally found a good thread with pictures for reference, http://www.classiczcars.com/topic/17542-treating-insideoutside-of-gas-tank-with-por15-products-and-removing-evaporation-tank/

He's deleting the tank though but still has some useful info.

 

Here's another picture that'll make you cringe.post-23570-0-43768900-1416482847_thumb.j

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Sdyck, I seem to recall the EZ coil instructions saying you can bend 90 deg max, but I think I could get nearly (not quite) 180 out of mine.  No issues that I know of.  ;)

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Use Goodyear E-Z coils for the bends:

 

http://www.veyance.com/productsDetail.aspx?id=17254

 

You can get larger size fuel hoses from a tractor supply house.  You can also buy some really nice marine-grade hose from a marine supply store.  If it's USCG marine-rated, then it's fuel resistant.  DON'T use heater hose!

 

I think your decision to keep the little tank is probably a good one.  I think it courts problems to buck the design.

I removed the vent tank with no problems whatsoever.  It is a U.S. Emissions device.  Non U.S. vehicles leave them out, per Nissan's design.  I even used a Nissan hose from a non-U.S. spec vehicle that deleted the tank.  That was many years ago and I don't have the P/N any longer.  It may be in the parts manual though.

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I eliminated all the vapor recovery lines etc - about 20 years ago. Never caused any issues/problems.{as long as you keep that top tank vent open - i.e. making that 180 without kinking the hose}.  Many of the 69 production 240Z's didn't even have it to begin with. Canada didn't require it, nor did the US in 1970. California did... and the rest of the US followed, so it became standard on all North American models.

 

So it isn't so much a design element - as a last minute add on for California in 1970. 

 

FWIW,

Carl B. 

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Be sure to inspect/replace all you rubber grommets in the back hatch as well - watch out - there are a couple that are hidden.  It will help with the fuel/exhaust smell

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