Venting about Venting - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jcfoote60 · 08-07-2005, 10:00 PM

OK so my Blazer tank install is almost done....I have went at this from all angles but am getting little response and seeing a few others out there with similar questions on venting these tanks. If you don't use a different fuel filler with vent tube already there and just use a bed or customer filler neck, what is being done with the large vent tube? I have just plugged the two small emission vent tubes for blazer use, but am left with the big vent tube. I had one reply that I could run it to a carbon canister....did my 72 come with one? I don't see it, just a metal line from my old saddle tank going forward to nowhere, also I got a response to just grab any canister from the bone yard...I guess I am concerned on how/where to connect the lines of a carbon canister and I plowed through 60 pages of posts and see one guy having problems with filling his tank even with the vent hose just hanging open venting to the great outdooors. The response in the thread said that until this guy moved his vent hose higher he would experience problems filling his tank.................

This is a big question mark for more than just me and although many cool conversions are going on out there with marker light fiillers, bed fillers, etc., there is litttle or no information on how and what to do with venting these gas tanks.

Trying to get good responses for all.................to benefit from.

JC

jhow66 · 08-07-2005, 10:19 PM

All we did on my son's (orangeuavol) was just use a vented cap. Plugged all the others except overflow (1" line) line that goes from tank to fill pipe.

**Tom Vogel** · 08-08-2005, 10:53 AM

My vent line went forward to the charcoal canister in the front passenger side of the truck. Ive ripped all that out though.
Since the new engine is supercharged, we had a custom stainless tank made to accomidate the required extra fuel flow. We have vented this tank (all tanks must be vented to allow fuel delivery), by installing a 3/8" npt fitting on top of the tank that will have an aluminum tubing coil with a breather to keep out dust.
If you have a stock type tank and are not worried about smog (if you are worried about passing smog, you will have to hook up the charcoal canister), then you can just hook a coil of some sort to the vent next to the pickup, and any small breather to keep out the dirt. All you are trying to accomplish here is to allow a way for air to enter the tank to take the place of the fuel that the engine is consuming.

sdredneck · 08-08-2005, 11:24 AM

My Charcoal Canister is located beneath the battery tray. My recomendation is you just fuel inject it and use the big vent for your fuel return.

jcfoote60 · 08-08-2005, 03:06 PM

Tom can you post a pic of this breather? What is it exactly and where can I get one? Also you mention a coil coming off of the NPT fitting.......again I am not getting a visual. Thanks for your help everyone!

jcfoote60 · 08-08-2005, 03:16 PM

Second thought.....based on what was said could I just attach a breather to the rubber vent hose, use nylon ties to secure it up alongside the fill hose to just where the fill hose goes into my bed area? It would be out of sight, out of mind and be elevated similar to the heighth of a normal Blazer setup.

PS- this is actually on a Blazer tank install in my 72 SWB not a Blazer or Jimmy. I was hopping between forums and posted this here in addition to over there. However I am not getting much feedback on the truck forum but you guys ROCK............Thanks!

08-07-2005, 10:00 PM	#1
jcfoote60 Active Member Join Date: Jun 2005 Location: Idaho Posts: 263	Venting about Venting OK so my Blazer tank install is almost done....I have went at this from all angles but am getting little response and seeing a few others out there with similar questions on venting these tanks. If you don't use a different fuel filler with vent tube already there and just use a bed or customer filler neck, what is being done with the large vent tube? I have just plugged the two small emission vent tubes for blazer use, but am left with the big vent tube. I had one reply that I could run it to a carbon canister....did my 72 come with one? I don't see it, just a metal line from my old saddle tank going forward to nowhere, also I got a response to just grab any canister from the bone yard...I guess I am concerned on how/where to connect the lines of a carbon canister and I plowed through 60 pages of posts and see one guy having problems with filling his tank even with the vent hose just hanging open venting to the great outdooors. The response in the thread said that until this guy moved his vent hose higher he would experience problems filling his tank................. This is a big question mark for more than just me and although many cool conversions are going on out there with marker light fiillers, bed fillers, etc., there is litttle or no information on how and what to do with venting these gas tanks. Trying to get good responses for all.................to benefit from. JC

08-07-2005, 10:19 PM	#2
jhow66 Registered User Join Date: Jun 2002 Location: Knoxville Tenn. Posts: 3,058	All we did on my son's (orangeuavol) was just use a vented cap. Plugged all the others except overflow (1" line) line that goes from tank to fill pipe. __________________ 56 Chevy Bel-Air 2dr. HT (purchased new) 71 Chevy Cheyenne SWB PU (502HO) 65 GMC short bed step--work in progress and my gofer

08-08-2005, 10:53 AM	#3
Tom Vogel 2WD Jimmy Join Date: Mar 2005 Location: Davis County, Utah Posts: 2,563	vents My vent line went forward to the charcoal canister in the front passenger side of the truck. Ive ripped all that out though. Since the new engine is supercharged, we had a custom stainless tank made to accomidate the required extra fuel flow. We have vented this tank (all tanks must be vented to allow fuel delivery), by installing a 3/8" npt fitting on top of the tank that will have an aluminum tubing coil with a breather to keep out dust. If you have a stock type tank and are not worried about smog (if you are worried about passing smog, you will have to hook up the charcoal canister), then you can just hook a coil of some sort to the vent next to the pickup, and any small breather to keep out the dirt. All you are trying to accomplish here is to allow a way for air to enter the tank to take the place of the fuel that the engine is consuming.

08-08-2005, 11:24 AM	#4
sdredneck The Crazy Kracka Join Date: Dec 2003 Location: San Diego, Ca Posts: 60	My Charcoal Canister is located beneath the battery tray. My recomendation is you just fuel inject it and use the big vent for your fuel return. __________________ My goal in life is to be as good of a person as my dog already thinks I am. 68 GMC LWB 396 BBC Camper Special 72 Chevy Blazer 4x4 with 406 SBC 73 Dodge Dart Sport with 340

08-08-2005, 03:06 PM	#5
jcfoote60 Active Member Join Date: Jun 2005 Location: Idaho Posts: 263	Tom can you post a pic of this breather? What is it exactly and where can I get one? Also you mention a coil coming off of the NPT fitting.......again I am not getting a visual. Thanks for your help everyone!

08-08-2005, 03:16 PM	#6
jcfoote60 Active Member Join Date: Jun 2005 Location: Idaho Posts: 263	Second thought.....based on what was said could I just attach a breather to the rubber vent hose, use nylon ties to secure it up alongside the fill hose to just where the fill hose goes into my bed area? It would be out of sight, out of mind and be elevated similar to the heighth of a normal Blazer setup. PS- this is actually on a Blazer tank install in my 72 SWB not a Blazer or Jimmy. I was hopping between forums and posted this here in addition to over there. However I am not getting much feedback on the truck forum but you guys ROCK............Thanks!



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