Charcoal Canister on rebuild

I'm about to start putting the fuel lines back in to my 72/304. Should I keep the 38 year old charcoal canister or is it fine to bypass it?

 

It does serve a purpose in keeping gas fumes down. If you don't mind a Jeep that reeks of gas every time you stop, you can get rid of it. They are easy to rebuild, the brillo-pad type filter on the bottom is still obtainable, and the canister is filled with activated charcoal, which you can buy at any pet store for aquarium filters for a couple of bucks.

 

I'd keep it. It's entirely passive, has no effect on performance, vents your gas tank properly, and helps clean the air. Plus rather than throwing away gas as fumes, they are returned to your engine and burned. Thus you save money ... though it's likely aminiscule savings.

I don't think they wear out. Run air through the charcoal for a while and it should revitalize it. The later ones have a flap valve in the top that wears out, but a '72 does not.

Realize that you must use the factory air cleaner for the canister to work properly.

What's not to like?

 

I had read somewhere that a canister from an old mustang would work if the old one is missing or in disrepair. I found one on eBay with just 2 ports like mine in my 73 304. I plan to try that out when I put my fuel system back together. My old cannister is brittle and missing parts.
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They are a commodity item, so it should work ok. The Jeep ones are Delco, at least in the later years. Some have 2 ports, some 3 and some 4, depending on the age. The main functional difference is that the later ones need a manifold vacuum signal to open a flap valve in the top of the canister. The early ones do not have any kind of valve in them, AFAIK.

 

If you go to a bone yard I'm sure you can find one that will work on your jeep.
They are all bascially the same system, vac from the engine pulls vapor from the canister.
Mount it up (or the line IN) higher than the tank or everytime you fill your tank to above that level it'll fill and when the engine draws the raw fuel in, it'll run crappy.
Try the old one and see if you smell fuel....
Many states now have emission cyctem checks when they do inspections and you'll need it.
Joe
it's a jeep, it really doesn't need anything but duct tape!

 

Please note... as on my 72' CJ5 Jeep.... The canister located under the rear drivers fenderwell... THIS CANISTER is a "VAPOR CANISTER (no charcoal within due to design... can verify this as I have owned this ol man since delivery at factory." and only purpose is to contain and direct hydrocarbon light end vapors safely back into the engine for disposal (via the shut-off valve .. ie: purge valve) during normal operation. Later year CJ power plants started utilizing the "Charcoal canister" to contain and also direct the vapors as the EPA has directed for their operation.

Hope this assists!

My suggestion is to NOT ByPASS... Suggest reinstalling and replace all 1/4" vapor hoses with appropriate Fuel quality vapor automotive tubing and appropriate clamps... ALSO, please ensure the Shut-Off valve (usually mounted on firewall) assembly is intact and operational on the firewall... the far-left pipette on the Vapor Canister is the outlet that directs (via fuel-vapor tubing to the Shut-off valve (purge valve) in the engine compartment on the firewall... this Shut-off valve then outlets into the engine via tubing and an appropriate Valve Cover grommet. The vapors are then consumed during normal internal combustion operation...

DO NOT BY_PASS the canister... fuel vapors are unpleasant and possibly become dangerous in appropriate quanity... should a spark or a cigarette/cigar smoker join your journey! ;o)

Gunner (EE, ME AE and PHD major: Hi-Energy Physics)

As one of the Sponsor on this website has also noted... Highly educated... but spend every day on or actually under my 1972 CJ-5. Would not want anything else... would not change anything!

Semper Fi to everyone on the Early CJ website!

 

Hey Gunner could you email me a picture of the shut-off valve on your firewall? I'm not entirely sure I have one.

 

Per Gunner, yes, the '72 setup is wierd compared to the later charcoal canisters. The '72 manual at www.trailforge.com will show the entire system. There's a canister, but I had not realized that it contains no charcoal.

The '73 and later canisters use charcoal to absorb the vapors, and the purge signal (a weak vacuum) comes from the air rushing into the air cleaner through the air cleaner snorkel. Later canisters use a valve and a connection to manifold vacuum for purge. You need to use a passive canister if you have the snorkel connection (2-3 nips, early style), and an active canister if you have a manifold vacuum connection (3-5 nips, later style).

Standard ignition sells a new canister for the later style that could be adapted if you have the early or late style canister - too much text needed to explain that here, but I'll make some discussion/references later if someone is needy and interested.

 

Certainly.... drop me an email with a web email address for attachment of the shutoff valve assembly located on the 1972 CJ's firewall... actually is mounted directly above the ignitions' resistor. banjo_pkr@me.com

Gunner Semper Fi to all.... Happy New year!

 

I have 2 cannisters on my 75.... 1 in the drivers side rear wheelwell.... and another attached to the radiator.... I reinstalled both... but didn't really feel a need to...

Gasseous

 

As of yet, I have not found any information on how each of the 5 ports on my 72 CJ5 vapor canister should be plumbed.

I am guessing that plumbing should be 1>2>3>vap-pipe-to-rear>C
- 6>A 7>B 8>D AND 9>E

I am hoping 72_CJ5_MUD is around and has documentation

 

Do you have the TSM? Do you have the charcoal canister? This is a V8 -




The tank with 5 connections is just an expansion tank. Connection C goes forward to the limit fill valve.

 

Thanks, that is what I was looking for. What source do those figures come from?

 

The TSM ...

 

I am working from a 1973 Technical Service Manual. Is there a source for a 1972 TSM?

 

Try here. Massive inventory. I've toured his inventory as it's in my home town.
I've also bought and sold manuals to them.

Faxon | Shop Manuals for Car & Truck Owners | DIY Service, Repair or Maintenance

 

You can buy it on CD from RockAuto for about $25. Printed copies are available from there and the Jeep retailers at a higher cost.

 

Just a comment - your '73 TSM will be fine for most things. However, emissions requirements and efforts to meet them were changing rapidly in that era, and you need the TSM for your exact year for that. '72 was the watershed year, and '73s are pretty much the same car... for '73, the colors change, the clutch linkage changed, Jeep added a float damper spring for the V8 (initially under a service bulletin), dash layout, trim and knobs changed, including heater controls and location of the optional gauges, and emissions/fuel/exhaust changes. That's all I can think of off the top of my head. The Wagoneer got the optional Quadratrac first in 1973 - a big change - but that does not affect the CJs. hth!

 

Reviving a very old post. For some reason my 71' has the Expansion tank but not the fuel tank vapor system. I have 5 outlets on the expansion tank. I am going to try to plumb it like the above diagram for 72 and see what happens. A line may have been misplaced when I dropped the tank. The line that goes to the engine is cut and has bee since I bought it 25 years back.