misisng vacuum lines ? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bimaldo · 07-09-2009, 12:20 AM

Can anyone help me figure out what I am misisng? This is from my 72 c20 350.
Is there a vacuum line diagram available anywhere?
What is supposed to connect to the thing in red box?

mikajo39 · 07-09-2009, 12:26 AM

Do you have A/c? im just taking a shot in the dark but it looks like (thing in red box)an idle compensator for when the a/c is on. and im pretty sure that line is for your PCV valve(coming off the carb)

bimaldo · 07-09-2009, 02:15 AM

no a/c in this truck. i'm pretty sure this carb is not stock.
Looks like previous owner replaced the stock with a 1984 model?
Would that just be useless, then?
thanks

Jacfourteen · 07-09-2009, 02:55 AM

Is this the stock engine? That has alot more vac lines than my 68 does, I know the 72's have a few more but it doesn't seem like there would be that many. If it came out of something else you'd have to find a vac diagram for that engine. Good luck, and hopefully someone else can be of more help than me!

bimaldo · 07-09-2009, 03:46 AM

I am not sure if this is the stock engine. I guess I would have to find the code on the engine.

brak · 07-09-2009, 08:09 AM

that looks like the exact setup that was in my 84 camaro. it's definately a later smog engine.

Red box is the Idle compensator. if you've no A/C nor the computer to control it, remove it.

IIRC the nipple on the front of the carb is for the EGR (pancake thingy on passenger side of manifold) theres a flap valve in the top portion of the carb for returned gasses or whatever... just cap it and forget it.

the orange thing in the water neck is a temperature controlled valve for the smog system. remove it, replace with a shiny new waterneck, a pretty pipe plug, or just ignore it.

Bottom line, you have half an emissions system on that truck, and half won't help, so remove it.

bimaldo · 07-09-2009, 09:29 PM

Thanks, I'll be fixing up this soon.

dwcsr · 07-09-2009, 11:38 PM

My 72 doesn't look anything like that. I think you have a car motor in there.

bimaldo · 07-11-2009, 07:44 PM

I'd be curious to see what it should look like.

*vegaschevy* · 08-21-2009, 01:35 PM

Quote:

Originally Posted by bimaldo

I'd be curious to see what it should look like.

ME too

OhioDan · 08-22-2009, 03:15 AM

Hope this might help?

07-09-2009, 12:20 AM	#1
bimaldo Registered User Join Date: Feb 2009 Location: columbus, oh Posts: 18	misisng vacuum lines ? Can anyone help me figure out what I am misisng? This is from my 72 c20 350. Is there a vacuum line diagram available anywhere? What is supposed to connect to the thing in red box? Attached Images

07-09-2009, 12:26 AM	#2
mikajo39 Gearhead and audio junkie Join Date: Aug 2008 Location: nunyah Posts: 452	Re: misisng vacuum lines ? Do you have A/c? im just taking a shot in the dark but it looks like (thing in red box)an idle compensator for when the a/c is on. and im pretty sure that line is for your PCV valve(coming off the carb) Last edited by mikajo39; 07-09-2009 at 12:28 AM.

07-09-2009, 02:15 AM	#3
bimaldo Registered User Join Date: Feb 2009 Location: columbus, oh Posts: 18	Re: misisng vacuum lines ? no a/c in this truck. i'm pretty sure this carb is not stock. Looks like previous owner replaced the stock with a 1984 model? Would that just be useless, then? thanks Attached Images

07-09-2009, 02:55 AM	#4
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: misisng vacuum lines ? Is this the stock engine? That has alot more vac lines than my 68 does, I know the 72's have a few more but it doesn't seem like there would be that many. If it came out of something else you'd have to find a vac diagram for that engine. Good luck, and hopefully someone else can be of more help than me! __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

07-09-2009, 03:46 AM	#5
bimaldo Registered User Join Date: Feb 2009 Location: columbus, oh Posts: 18	Re: misisng vacuum lines ? I am not sure if this is the stock engine. I guess I would have to find the code on the engine.

07-09-2009, 08:09 AM	#6
brak Registered User Join Date: Apr 2006 Location: MinneSNOWta Posts: 1,381	Re: misisng vacuum lines ? that looks like the exact setup that was in my 84 camaro. it's definately a later smog engine. Red box is the Idle compensator. if you've no A/C nor the computer to control it, remove it. IIRC the nipple on the front of the carb is for the EGR (pancake thingy on passenger side of manifold) theres a flap valve in the top portion of the carb for returned gasses or whatever... just cap it and forget it. the orange thing in the water neck is a temperature controlled valve for the smog system. remove it, replace with a shiny new waterneck, a pretty pipe plug, or just ignore it. Bottom line, you have half an emissions system on that truck, and half won't help, so remove it. __________________ 2003 GMC Sierra 1500 WT 1995 Nissan Hardbody 2016 Hyundai Veloster Turbo DC2 (SW/AW) Clyde W. Harvey USN "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery" Winston Churchill

07-09-2009, 09:29 PM	#7
bimaldo Registered User Join Date: Feb 2009 Location: columbus, oh Posts: 18	Re: misisng vacuum lines ? Thanks, I'll be fixing up this soon.

07-09-2009, 11:38 PM	#8
dwcsr Hollister Road Co. Join Date: Apr 2005 Location: Houston Posts: 6,131	Re: misisng vacuum lines ? My 72 doesn't look anything like that. I think you have a car motor in there.

07-11-2009, 07:44 PM	#9
bimaldo Registered User Join Date: Feb 2009 Location: columbus, oh Posts: 18	Re: misisng vacuum lines ? I'd be curious to see what it should look like.

08-22-2009, 03:15 AM	#11
OhioDan Registered User Join Date: Apr 2002 Location: New Carlisle, Ohio,USA Posts: 1,404	Re: misisng vacuum lines ? Hope this might help? Attached Images __________________ LIFE AIN'T EASY WHEN YER FAT AND GREASY! GMC= Got More Class! 1970 GMC LWB, Fleetside, 350/4spd, Flowmaster "40's", 2002 GMC 16" Rallies, cowl hood,and added a bunch of options that weren't there when I started.



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