Need some serious help... emission system !!!! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Vic1970 · 08-14-2002, 11:53 PM

I have a 1970 GMC C1500 pickup... with a emmission system that I can't figure out. The canister has three lines coming out of it. The tank and PCV lines I can handle --- it is the one mark air cleaner I can't sort out. It is connected to a metal tube that appears to bolt to the bottom of the passenger side valve cover... and then it connects somewhere. It appears it once connected to the air horn of the air cleaner... I know everyone thinks I'm crazy... I tried to attached some photos but could not make it to happen.. so I will be happy to email you a copy if it will help understand what I'm talking about. I would like to figure out how this monster once went together.... I think I'm missing a hose and a component that fits into the whole on the bottom of the air cleaner.... \

Check every book I can find in four libraries and no luck... can anyone HELP me...

Thanks

Vic 1970

O'l Buck · 08-15-2002, 01:32 AM

i'm kinda lost here....the only metal tube i can think of that would be in the vicinity of the valve cover is the heat riser for the choke, or possible the vacuum tube for the vacuum modulator.

colohusker · 08-15-2002, 01:42 AM

here's some pics I resized for vic1970. He can add the explanation tomorrow.

pic 1 - canister

colohusker · 08-15-2002, 01:43 AM

The tube it connects to:

colohusker · 08-15-2002, 01:44 AM

another view of the tube:

colohusker · 08-15-2002, 01:45 AM

bottom of the horn on the air cleaner:

colohusker · 08-15-2002, 01:46 AM

another view of the horn on the air cleaner:

colohusker · 08-15-2002, 01:52 AM

and here's the canister assembly:

O'l Buck · 08-15-2002, 01:54 AM

Ok, thanks for the pics Scott.....now i'm not so lost. I've never seen one of those systems working, but I think the tube comming from the canister that says "air cleaner" is supposed to run to a nipple on the breather snorkel which is apparently broke off or was a plastic piece that can be replace......

My thinking on this is it is a vent from the canister and it feeds to the air cleaner to draw the vapors and burn them instead of just venting into the air.

68 Suburban · 08-15-2002, 06:26 AM

Scott, that is an interesting shade of finger nail polish you are wearing!! :p

Vic1970 · 08-15-2002, 08:03 AM

Why is it, I get to have the only one in the world...??!!! @%#*

Scott thanks for posting the pictures.

I agree with o'l Buck that the system connects to bottom of the air cleaner... does anyone have a part number? or any idea where I can find one. I have been through all the junk yards in the area with no luck... I think it is an early Calif emission system, even my gas tank is mark "CAL", heck even the carb is different and have not been able to track down anything like it...

Thanks for your help up front...

Vic 1970

colohusker · 08-15-2002, 10:30 AM

LOL, isn't it though? Wish I was working on something that clean, but I just resized and posted the pictures, wasn't actually there.

Scott

Vic1970 · 08-15-2002, 10:48 AM

The finger nail polish is very nice on my daughters hands... and yes they are clean...

BUT what about the tube on the engine... LOL... somebody has got to know... right?

Vic 1970

**jerry moss** · 08-15-2002, 12:39 PM

i just checked my 72 that has a canister, one line tees into the pcv, one line to the tank and the third is hooked to a nipple on the side of the carb under the choke pull off. i'm assuming it's correct routing as it passed calif emissions last time we had to smog it and i have not changed anything since then. your canister is different than mine in appearance, mine has three different size hoses and the one hooked to the side of the carb is pretty small. i hope this helps but it probably makes it more confusing.

Michael A. K. G · 08-15-2002, 01:06 PM

Huh??

You never have to smog a '72 in California. Never.

Are you sure you're talking about the same year truck? The emissions systems changed very quickly in the early '70s.

**jerry moss** · 08-15-2002, 05:16 PM

Michael,
re-read my post !!!!!!!!
i know we don't have to smog them now, but there was a time, not too long ago, that we did. we had to smog anything 55 and newer for a while, even though 65 and older never had smog equipment on them. i work in a calif. certified smog shop and have been there for 17 years as a muffler/exhaust person. one thing for you to think about-- the new software we got for our smog machine has everything on it for 66-73s, i doubt they would spend the money to put that information on the updated software if there wasn't plans to use it in the near future.
and FYI--i do know a little about these trucks, i have been in and around them since 1969. in that time i've owned over 200 of them in one form or another.
have a nice day.

Vic1970 · 08-15-2002, 09:03 PM

Jerry, what do you think the hole in the air cleaner is for? I have looked many and I can find no other air cleaner air horn like it... we have owned the truck (Dad can't remember what was there and he did not drill a hole.

Also, I don't need the tube to run a line to the carb... and I have looked and I can find no connection on the orginal carb or manifold I have.

Tough one but I know that someone out there can tell us....

VIc 1970

Super Chevy · 08-15-2002, 09:06 PM

I have the same thing in my 72 chevy, i bypassed it, no emissions for trucks and cars 1975 and below here

**jerry moss** · 08-15-2002, 09:07 PM

Vic,
i've never seen the hole in the end of the air cleaner. hopefully someone here will be able to help. best of luck.

08-14-2002, 11:53 PM	#1
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Need some serious help... emission system !!!! I have a 1970 GMC C1500 pickup... with a emmission system that I can't figure out. The canister has three lines coming out of it. The tank and PCV lines I can handle --- it is the one mark air cleaner I can't sort out. It is connected to a metal tube that appears to bolt to the bottom of the passenger side valve cover... and then it connects somewhere. It appears it once connected to the air horn of the air cleaner... I know everyone thinks I'm crazy... I tried to attached some photos but could not make it to happen.. so I will be happy to email you a copy if it will help understand what I'm talking about. I would like to figure out how this monster once went together.... I think I'm missing a hose and a component that fits into the whole on the bottom of the air cleaner.... \ Check every book I can find in four libraries and no luck... can anyone HELP me... Thanks Vic 1970

08-15-2002, 01:32 AM	#2
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	i'm kinda lost here....the only metal tube i can think of that would be in the vicinity of the valve cover is the heat riser for the choke, or possible the vacuum tube for the vacuum modulator. __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

08-15-2002, 01:42 AM	#3
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	here's some pics I resized for vic1970. He can add the explanation tomorrow. pic 1 - canister Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:43 AM	#4
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	The tube it connects to: Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:44 AM	#5
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	another view of the tube: Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:45 AM	#6
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	bottom of the horn on the air cleaner: Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:46 AM	#7
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	another view of the horn on the air cleaner: Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:52 AM	#8
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	and here's the canister assembly: Attached Images __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 01:54 AM	#9
O'l Buck Recovering Truck Driver Join Date: Mar 2002 Location: Orleans, NE USA Posts: 1,883	Ok, thanks for the pics Scott.....now i'm not so lost. I've never seen one of those systems working, but I think the tube comming from the canister that says "air cleaner" is supposed to run to a nipple on the breather snorkel which is apparently broke off or was a plastic piece that can be replace...... My thinking on this is it is a vent from the canister and it feeds to the air cleaner to draw the vapors and burn them instead of just venting into the air. __________________ 67 K-20 350, SM465, Eaton rear, 4.56 no spin option 00 Dodge 2500 4x4, 24V cummins, 5 speed Chad South Central Nebraska

08-15-2002, 06:26 AM	#10
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	Scott, that is an interesting shade of finger nail polish you are wearing!! :p __________________ Just sitting here contemplating contemplation.

08-15-2002, 08:03 AM	#11
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	The only one? Why is it, I get to have the only one in the world...??!!! @%#* Scott thanks for posting the pictures. I agree with o'l Buck that the system connects to bottom of the air cleaner... does anyone have a part number? or any idea where I can find one. I have been through all the junk yards in the area with no luck... I think it is an early Calif emission system, even my gas tank is mark "CAL", heck even the carb is different and have not been able to track down anything like it... Thanks for your help up front... Vic 1970

08-15-2002, 10:30 AM	#12
colohusker Registered User Join Date: Apr 2002 Location: Longmont, CO Posts: 436	LOL, isn't it though? Wish I was working on something that clean, but I just resized and posted the pictures, wasn't actually there. Scott __________________ ------------------------------------------------ I say it's only money, my wife says it's only a truck.... '71 C10 Deluxe, factory ac, ps, pb, should be done by 2102 Longmont, CO husker95@hotmail.com

08-15-2002, 10:48 AM	#13
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	OK OK lets get to the issue The finger nail polish is very nice on my daughters hands... and yes they are clean... BUT what about the tube on the engine... LOL... somebody has got to know... right? Vic 1970

08-15-2002, 12:39 PM	#14
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,936	i just checked my 72 that has a canister, one line tees into the pcv, one line to the tank and the third is hooked to a nipple on the side of the carb under the choke pull off. i'm assuming it's correct routing as it passed calif emissions last time we had to smog it and i have not changed anything since then. your canister is different than mine in appearance, mine has three different size hoses and the one hooked to the side of the carb is pretty small. i hope this helps but it probably makes it more confusing. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

08-15-2002, 01:06 PM	#15
Michael A. K. G Registered User Join Date: Jul 2002 Location: California central coast Posts: 126	Huh?? You never have to smog a '72 in California. Never. Are you sure you're talking about the same year truck? The emissions systems changed very quickly in the early '70s.



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08-15-2002, 05:16 PM	#16
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,936	Michael, re-read my post !!!!!!!! i know we don't have to smog them now, but there was a time, not too long ago, that we did. we had to smog anything 55 and newer for a while, even though 65 and older never had smog equipment on them. i work in a calif. certified smog shop and have been there for 17 years as a muffler/exhaust person. one thing for you to think about-- the new software we got for our smog machine has everything on it for 66-73s, i doubt they would spend the money to put that information on the updated software if there wasn't plans to use it in the near future. and FYI--i do know a little about these trucks, i have been in and around them since 1969. in that time i've owned over 200 of them in one form or another. have a nice day. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

08-15-2002, 09:03 PM	#17
Vic1970 Registered User Join Date: Mar 2002 Location: Holden MO Posts: 82	Jerry, what do you think the hole in the air cleaner is for? I have looked many and I can find no other air cleaner air horn like it... we have owned the truck (Dad can't remember what was there and he did not drill a hole. Also, I don't need the tube to run a line to the carb... and I have looked and I can find no connection on the orginal carb or manifold I have. Tough one but I know that someone out there can tell us.... VIc 1970

08-15-2002, 09:06 PM	#18
Super Chevy Registered User Join Date: Feb 2001 Location: Ohio Posts: 1,025	I have the same thing in my 72 chevy, i bypassed it, no emissions for trucks and cars 1975 and below here

08-15-2002, 09:07 PM	#19
jerry moss Born Psycho Join Date: Feb 2001 Location: brentwood,cal,usa Posts: 4,936	Vic, i've never seen the hole in the end of the air cleaner. hopefully someone here will be able to help. best of luck. __________________ jerry moss 72 cheyenne super K20- tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,tow hooks,bumper guards,toolbox,aux. fuel tank,posi front and rear,plus other goodies!!! SOLD 69 suburban K20-tilt,tach,vacuum,speedwarning,buckets,shoulder belts,am/fm,4 inch all spring lift,4 speed, 14 bolt full floater, dana 44 HD,warn winch,posi front and rear,tow hooks,plus other goodies. 73/80 chevy/gmc K20 SB400,turbo 400,205,tilt,a-c,gas hog. 77 K/5 cheyenne blazer-daily driver/beater. SON HAS IT NOW BRENTWOOD,CALIFORNIA

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