need carb. help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

hdrider · 02-21-2008, 08:45 PM

havent had my head under the hood for quite some time...gotta 1982 GMC pick up with a 5.0...quadrajet took a dump...cant be rebuilt...friend of mine handed me a freshley rebuilt holley that i mounted...how do i reroute the vaccume lines like the brake vaccume assist & the pcv valve & that gas canister that is mounted by the headlamp...what lines or devices do i leave out or cap...is there a web site that has a diagram of this...dont want to do a sloppy job & leave things hanging...appreciate any help...thanks

James McClure · 02-21-2008, 09:48 PM

HD. Directly behind the carb mounting flange there should be a vacuum tree that will supply you with manifold vacuum. Any of the lines which need "ported" vacuum like the EGR you can find on the new carb. I'm not a big fan of Holley unless your into raceing and you like fooling around with jetting. If I were you I would have taken the old one to NAPA and swaped it out. jim

hdrider · 02-21-2008, 10:00 PM

are you refering to the port that is pointing up on the backside if manifold...is it ok to split off of this to whatever i need......thanks

Thumpin455 · 02-22-2008, 01:26 AM

Some things need timed vacuum, others ported. Timed is above the throttle plates and only gets vacuum when the throttle is opened far enough. On a Holley those are usually on the metering blocks. The ports in the base plate are usually the ported sources.

The way to be sure if its ported or times is to start the engine, then put your finger over the open port, If it is sucking at idle, then its ported, if you need to move the throttle to get some vacuum, its timed.

If you dont have a computer Qjet, you could mail it to me. I rebuild them in my spare time, and would do yours. Since my 87 had a regular Qjet on it, I doubt its a computer one. I am no fan of the 'rebuilt' carbs from parts stores and the like. They usually have issues, but will often work ok on a very mild small cid engine.

I like the Qjet, they arent that difficult to rebuild, the thing about them is they are so adjustable that you can go the wrong way so fast and easily that you get lost. Most people are clueless about a carb, its not a slam its just how it is. If you think about how many people can rebuild a transmission, then the number of people who can rebuild a carb right would be similar. Its not like changing a tire, and a huge number of people in the USA cant do that. It isnt taught in Votech schools anymore, everything is EFI and its tough to find someone who can adjust dwell on points. It isnt as prevalent as it used to be, so they dont teach it.

So if you dont know about carbs, its ok, it is something you can learn if you go about it the right way. You cant learn it by reading only, you have to do it, with your own hands, and test it on the engine you plan to use it on. You also have to learn how it works, that way you can figure out what it is doing wrong.

Wow went off on a tangent there..

Even if you dont want it rebuilt, send me your old carb.. I will take it off your hands rather than it getting scrapped.

benoit454 · 02-22-2008, 02:02 AM

I agree I hate reman. carbs from parts stores, and I just recently rebuilt my first carb and edelbrock to replace the q-jet on our 84. It was easier then I thought and works great.

I done away with everything, egr and all when I done ours, just used the vac. advance and power brakes and pcv and that was all. the rest i traced and removed.

My next rebuild I plan to attempt the quadrajet rebuild and see how it goes.

Thumpin455 · 02-22-2008, 05:03 AM

Quote:

Originally Posted by benoit454

I agree I hate reman. carbs from parts stores, and I just recently rebuilt my first carb and edelbrock to replace the q-jet on our 84. It was easier then I thought and works great.

I done away with everything, egr and all when I done ours, just used the vac. advance and power brakes and pcv and that was all. the rest i traced and removed.

My next rebuild I plan to attempt the quadrajet rebuild and see how it goes.

If you want to do it and do it right, buy this book. Amazon has them, as well as Barnes and Noble can order them. The man knows his stuff, and I dont get paid for tellin people about him either..

How to Rebuild and Modify Rochester Quadrajet Carburetors
by Cliff Ruggles

I bought it and learned more about them too, and I have been making them work pretty good since the mid 80s.

benoit454 · 02-22-2008, 08:15 AM

already got that book lol I picked it up at the local booksamillion store while out with my wife and my mom and grandma.

James McClure · 02-22-2008, 07:31 PM

Thumpin got it right except for this. Take the number of people who can rebuild a trans and devide by 4 and you'll have the number of folks who can do carbs and do them right. Devide by 10 and you'll have the number who even know what points are never mind adjusting them properly. I rebuild QJ's quite often, but am haveing greater and greater trouble getting GM rebuild kits and I don't like the one's offered by NAPA. If I find anymore for mine I'm going to snatch up as many as I can get my hands on.

Jim

hdrider · 02-22-2008, 08:01 PM

thanks for all the feedback...want to put a quad back on...but for now i just need it up & runnin.

Thumpin455 · 02-22-2008, 10:23 PM

The Holley will work to make it mobile, dont be afraid to use it, they are good carbs. Just dont junk the Qjet, they are good too.

James, Cliff sells complete rebuild kits, more parts than the GM kits and everything is quality. Call him with the number on your carb and he will send you a kit. It costs more but its much more than just a gasket set.

James McClure · 02-23-2008, 12:17 AM

Thump, you have his number?? Thanks, jim

Thumpin455 · 02-23-2008, 01:16 AM

http://www.cliffshighperformance.com/

paulrpjl · 02-29-2008, 11:04 AM

Q-jets are the best if you take all the steps to assure they run well. I work at the Carburetor Refactory over in Richmond, CA. (www.carbkits.com). Q-jets are our bread and butter, much preferred over any aftermarket carb, any day. All Holley's have throttle shaft play you'd expect on a carb that had at least 50,000 miles on it.

02-21-2008, 08:45 PM	#1
hdrider Registered User Join Date: Feb 2008 Location: oldsmar fl Posts: 22	need carb. help havent had my head under the hood for quite some time...gotta 1982 GMC pick up with a 5.0...quadrajet took a dump...cant be rebuilt...friend of mine handed me a freshley rebuilt holley that i mounted...how do i reroute the vaccume lines like the brake vaccume assist & the pcv valve & that gas canister that is mounted by the headlamp...what lines or devices do i leave out or cap...is there a web site that has a diagram of this...dont want to do a sloppy job & leave things hanging...appreciate any help...thanks Last edited by hdrider; 02-21-2008 at 09:30 PM.

02-21-2008, 09:48 PM	#2
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: need carb. help HD. Directly behind the carb mounting flange there should be a vacuum tree that will supply you with manifold vacuum. Any of the lines which need "ported" vacuum like the EGR you can find on the new carb. I'm not a big fan of Holley unless your into raceing and you like fooling around with jetting. If I were you I would have taken the old one to NAPA and swaped it out. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

02-21-2008, 10:00 PM	#3
hdrider Registered User Join Date: Feb 2008 Location: oldsmar fl Posts: 22	Re: need carb. help are you refering to the port that is pointing up on the backside if manifold...is it ok to split off of this to whatever i need......thanks

02-22-2008, 01:26 AM	#4
Thumpin455 My truck is an alcoholic Join Date: Nov 2007 Location: Marquette Mi Posts: 303	Re: need carb. help Some things need timed vacuum, others ported. Timed is above the throttle plates and only gets vacuum when the throttle is opened far enough. On a Holley those are usually on the metering blocks. The ports in the base plate are usually the ported sources. The way to be sure if its ported or times is to start the engine, then put your finger over the open port, If it is sucking at idle, then its ported, if you need to move the throttle to get some vacuum, its timed. If you dont have a computer Qjet, you could mail it to me. I rebuild them in my spare time, and would do yours. Since my 87 had a regular Qjet on it, I doubt its a computer one. I am no fan of the 'rebuilt' carbs from parts stores and the like. They usually have issues, but will often work ok on a very mild small cid engine. I like the Qjet, they arent that difficult to rebuild, the thing about them is they are so adjustable that you can go the wrong way so fast and easily that you get lost. Most people are clueless about a carb, its not a slam its just how it is. If you think about how many people can rebuild a transmission, then the number of people who can rebuild a carb right would be similar. Its not like changing a tire, and a huge number of people in the USA cant do that. It isnt taught in Votech schools anymore, everything is EFI and its tough to find someone who can adjust dwell on points. It isnt as prevalent as it used to be, so they dont teach it. So if you dont know about carbs, its ok, it is something you can learn if you go about it the right way. You cant learn it by reading only, you have to do it, with your own hands, and test it on the engine you plan to use it on. You also have to learn how it works, that way you can figure out what it is doing wrong. Wow went off on a tangent there.. Even if you dont want it rebuilt, send me your old carb.. I will take it off your hands rather than it getting scrapped. __________________ Too much stuff, too many projects to list everything. my 454 urged 76 swb beater

02-22-2008, 02:02 AM	#5
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: need carb. help I agree I hate reman. carbs from parts stores, and I just recently rebuilt my first carb and edelbrock to replace the q-jet on our 84. It was easier then I thought and works great. I done away with everything, egr and all when I done ours, just used the vac. advance and power brakes and pcv and that was all. the rest i traced and removed. My next rebuild I plan to attempt the quadrajet rebuild and see how it goes. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

02-22-2008, 08:15 AM	#7
benoit454 Chris Join Date: Nov 2004 Location: Monaville, WV Posts: 3,737	Re: need carb. help already got that book lol I picked it up at the local booksamillion store while out with my wife and my mom and grandma. __________________ Chris GIT R DONE!!!!!! Check out all our rides, http://www.cardomain.com/id/benwa454

02-22-2008, 07:31 PM	#8
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: need carb. help Thumpin got it right except for this. Take the number of people who can rebuild a trans and devide by 4 and you'll have the number of folks who can do carbs and do them right. Devide by 10 and you'll have the number who even know what points are never mind adjusting them properly. I rebuild QJ's quite often, but am haveing greater and greater trouble getting GM rebuild kits and I don't like the one's offered by NAPA. If I find anymore for mine I'm going to snatch up as many as I can get my hands on. Jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

02-22-2008, 08:01 PM	#9
hdrider Registered User Join Date: Feb 2008 Location: oldsmar fl Posts: 22	Re: need carb. help thanks for all the feedback...want to put a quad back on...but for now i just need it up & runnin.

02-22-2008, 10:23 PM	#10
Thumpin455 My truck is an alcoholic Join Date: Nov 2007 Location: Marquette Mi Posts: 303	Re: need carb. help The Holley will work to make it mobile, dont be afraid to use it, they are good carbs. Just dont junk the Qjet, they are good too. James, Cliff sells complete rebuild kits, more parts than the GM kits and everything is quality. Call him with the number on your carb and he will send you a kit. It costs more but its much more than just a gasket set. __________________ Too much stuff, too many projects to list everything. my 454 urged 76 swb beater

02-23-2008, 12:17 AM	#11
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: need carb. help Thump, you have his number?? Thanks, jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.

02-23-2008, 01:16 AM	#12
Thumpin455 My truck is an alcoholic Join Date: Nov 2007 Location: Marquette Mi Posts: 303	Re: need carb. help http://www.cliffshighperformance.com/ __________________ Too much stuff, too many projects to list everything. my 454 urged 76 swb beater

02-29-2008, 11:04 AM	#13
paulrpjl Registered User Join Date: Feb 2008 Location: Richmond, CA Posts: 1	Re: need carb. help Q-jets are the best if you take all the steps to assure they run well. I work at the Carburetor Refactory over in Richmond, CA. (www.carbkits.com). Q-jets are our bread and butter, much preferred over any aftermarket carb, any day. All Holley's have throttle shaft play you'd expect on a carb that had at least 50,000 miles on it.



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