1972 GMC Q-Jet, Rebuild? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ed2552 · 02-06-2012, 04:42 PM

So my Grandpa's 72 GMC (350/TH400) is having carb issues. My plan is to tear the Q-jet apart over spring break and rebuild it, and do new cap/rotor/plugs/wires, but my question is where is the best place to get a rebuild kit/instructions for the Q-jet? The only other carbs I've worked on have been on B&S small engines, super simple carbs.

FWIW, the issue is it won't idle, period, and it doesn't want to go down into drive. I'm going to inspect/replace vac lines, but it definitely feels like more of a carb issue.

Thanks guys.

webfoot · 02-06-2012, 04:57 PM

Cliff Ruggles (q-jet expert and author of a few boks on them) sells various levels of rebuild kits on his website (just google his name) and I also recommend the book.

Otherwise NAPA will have a basic q-jet rebuild kit.

FWIW not going into drive doesn't sound like a carb issue.

ed2552 · 02-06-2012, 04:58 PM

It goes into drive, but immediately dies. I think the idle circuit of the carb is all gummed up, the truck rarely gets driven and sat for over 3 years at one point.

Thanks for the info.

webfoot · 02-06-2012, 05:05 PM

Oh I see, makes sense now. Carb could be all gummed up if it sat that long.

ed2552 · 02-06-2012, 05:08 PM

Yep, that's what we're thinking. At $40 for a rebuild kit I think that's the way to go.

webfoot · 02-06-2012, 05:11 PM

Good luck with the project. I just rebuilt my first quadrajet recently and am very happy with the results. Basic rebuild kit plus new jets and rods. truck runs better than ever and the smell of it idling doesn't burn my nose and eyes anymore.

There are some good videos on youtube as well if you need to see how it is done from something besides a picture.

MARKDTN · 02-06-2012, 05:48 PM

Rebuilding a Qjet is not always simple. I have had no luck building them myself. Don't get me wrong, it is an excellent carb when properly tuned. I can rebuild an engine, I can build a Holley, but I can't build a Qjet. I have had a few done by The Carb Shop in Ontario, CA with excellent results. There is also a guy named Lars in Colorado that has a good reputation in the Corvette community with building them. Good luck with what you do.

geezer#99 · 02-06-2012, 06:26 PM

A link for Lars.
http://www.digitalcorvettes.com/foru...ad.php?t=88376
And more info.
http://www.florida4x4.com/tech/quadrajet/

02-06-2012, 04:42 PM	#1
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	1972 GMC Q-Jet, Rebuild? So my Grandpa's 72 GMC (350/TH400) is having carb issues. My plan is to tear the Q-jet apart over spring break and rebuild it, and do new cap/rotor/plugs/wires, but my question is where is the best place to get a rebuild kit/instructions for the Q-jet? The only other carbs I've worked on have been on B&S small engines, super simple carbs. FWIW, the issue is it won't idle, period, and it doesn't want to go down into drive. I'm going to inspect/replace vac lines, but it definitely feels like more of a carb issue. Thanks guys. __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A

02-06-2012, 04:57 PM	#2
webfoot Registered User Join Date: Nov 2007 Location: Hermiston, OR Posts: 947	Re: 1972 GMC Q-Jet, Rebuild? Cliff Ruggles (q-jet expert and author of a few boks on them) sells various levels of rebuild kits on his website (just google his name) and I also recommend the book. Otherwise NAPA will have a basic q-jet rebuild kit. FWIW not going into drive doesn't sound like a carb issue. __________________ *Running in place gets you nowhere fast.* -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC.

02-06-2012, 04:58 PM	#3
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	Re: 1972 GMC Q-Jet, Rebuild? It goes into drive, but immediately dies. I think the idle circuit of the carb is all gummed up, the truck rarely gets driven and sat for over 3 years at one point. Thanks for the info. __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A

02-06-2012, 05:05 PM	#4
webfoot Registered User Join Date: Nov 2007 Location: Hermiston, OR Posts: 947	Re: 1972 GMC Q-Jet, Rebuild? Oh I see, makes sense now. Carb could be all gummed up if it sat that long. __________________ *Running in place gets you nowhere fast.* -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC.

02-06-2012, 05:08 PM	#5
ed2552 Registered User Join Date: Jan 2007 Location: Charles City IA Posts: 1,626	Re: 1972 GMC Q-Jet, Rebuild? Yep, that's what we're thinking. At $40 for a rebuild kit I think that's the way to go. __________________ '67 C20, Under the Knife!, LWB, Eaton HO-52, Rear Coil Springs 72' GMC C2500, 350, TH400(?), Dana 60 '67 K10 4-spd., 305, SM465, Dana 44, 12 Bolt, RUST! '65 C60 292, 4 spd, 2 spd Rearend, 15' Grain Box, MINT! 09 Yukon Denali 82k Miles 6.2L/6A

02-06-2012, 05:11 PM	#6
webfoot Registered User Join Date: Nov 2007 Location: Hermiston, OR Posts: 947	Re: 1972 GMC Q-Jet, Rebuild? Good luck with the project. I just rebuilt my first quadrajet recently and am very happy with the results. Basic rebuild kit plus new jets and rods. truck runs better than ever and the smell of it idling doesn't burn my nose and eyes anymore. There are some good videos on youtube as well if you need to see how it is done from something besides a picture. __________________ *Running in place gets you nowhere fast.* -me 1968 GTO 4-spd covnvertible 1970 K-20 4-speed, factory AC.

02-06-2012, 05:48 PM	#7
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,160	Re: 1972 GMC Q-Jet, Rebuild? Rebuilding a Qjet is not always simple. I have had no luck building them myself. Don't get me wrong, it is an excellent carb when properly tuned. I can rebuild an engine, I can build a Holley, but I can't build a Qjet. I have had a few done by The Carb Shop in Ontario, CA with excellent results. There is also a guy named Lars in Colorado that has a good reputation in the Corvette community with building them. Good luck with what you do. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

02-06-2012, 06:26 PM	#8
geezer#99 Registered User Join Date: Aug 2009 Location: Bowser Posts: 13,715	Re: 1972 GMC Q-Jet, Rebuild? A link for Lars. http://www.digitalcorvettes.com/foru...ad.php?t=88376 And more info. http://www.florida4x4.com/tech/quadrajet/

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