Q-Jet Question
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
The most common cause with hard starts is either an incorrectly adjusted choke or leaking bowl plugs...which is very common on Q-Jets. They typically get replaced and epoxy'd during overhaul.
I'm in the Q-Jet camp if you're working to keep the car original and aren't doing a bunch of performance upgrades. I would plan to spend the $$$ to get it overhauled by one of the very few quality Q-Jet rebuilders - easy to find here on the Forum.
I'm in the Q-Jet camp if you're working to keep the car original and aren't doing a bunch of performance upgrades. I would plan to spend the $$$ to get it overhauled by one of the very few quality Q-Jet rebuilders - easy to find here on the Forum.
Le Mans Master
Joined: Oct 2002
Posts: 7,098
Likes: 378
From: Las Vegas - Just stop perpetuating myths please.
This is getting humorous.
Every time this thread bounces up with a new post i get a good laugh.
The OP has a big block car that runs great but with a small block Qjet carb asking if he is missing some power without the original carb. Yet some post like he wouldn't have to tune the carb for more hp. At the very least he needs to find check the tune he has now. And again he doesn't have the original carb so its set up is questionable for his BB (but is possible the previous owners did it right).
For his own experience he needs to learn to adjust and tune what he's got. The fact is no carb is 100% ready to bolt on without tuning/adjustments.
Why waste money while on the learning curve with Qjets.
There's plenty to adjust on what he has before hes spends more $$$ on another carb he will have to learn to tune anyways.
Let the guy sort things out. His carb is working fine now. Changing secondary rods takes no effort - just some fun. Then an intro to linkage bendology will keep him busy for a long time.
cardo0
The OP has a big block car that runs great but with a small block Qjet carb asking if he is missing some power without the original carb. Yet some post like he wouldn't have to tune the carb for more hp. At the very least he needs to find check the tune he has now. And again he doesn't have the original carb so its set up is questionable for his BB (but is possible the previous owners did it right).
For his own experience he needs to learn to adjust and tune what he's got. The fact is no carb is 100% ready to bolt on without tuning/adjustments.
Why waste money while on the learning curve with Qjets. There's plenty to adjust on what he has before hes spends more $$$ on another carb he will have to learn to tune anyways.Let the guy sort things out. His carb is working fine now. Changing secondary rods takes no effort - just some fun. Then an intro to linkage bendology will keep him busy for a long time.
cardo0
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
I hope you are right. I am in this boat right now. I bought an '80 on eBay (by accident, funny story) that had a great body and chassis rebuild before the guy ran out of money... It has a crate 350 with an '80 Qjet.
In an attempt to educate myself on the workings of the carb, I took an older '70s Qjet that my brother had lying around and overhauled it. I bolted it on and the car fired right away! It was running rich and had filled the garage with smoke but it ran for 5 minutes. I turned the car off to make some adjustments and ventilate the garage and haven't gotten it to fire up again. When it was running and when I crank on it now there is gas dripping from the elbow valve on the bottom of the vapor canister. I assume I don't have the APT deep enough. When I overhaul the carb that goes back on the car, I won't be removing the APT! The Ruggles book is ordered. Any other suggestions?
In an attempt to educate myself on the workings of the carb, I took an older '70s Qjet that my brother had lying around and overhauled it. I bolted it on and the car fired right away! It was running rich and had filled the garage with smoke but it ran for 5 minutes. I turned the car off to make some adjustments and ventilate the garage and haven't gotten it to fire up again. When it was running and when I crank on it now there is gas dripping from the elbow valve on the bottom of the vapor canister. I assume I don't have the APT deep enough. When I overhaul the carb that goes back on the car, I won't be removing the APT! The Ruggles book is ordered. Any other suggestions?
Thread Starter
Safety Car
Joined: Sep 2011
Posts: 4,115
Likes: 1,230
From: Madeira Beach, FL
2024 C8 of the Year Finalist - Unmodified
2024 C2 of the Year Finalist - Unmodified
2023 C2 of the Year Finalist - Unmodified
2020 C3 of the Year Finalist - Unmodified
Thanks everyone for the help. I'm going to get a good book as rec. on Q-Jets and rebuild what I have or if cheap enough get a spare carb and rebuild it while I continue tol drive.
The forum also saved my but in another post. I was interested in a 427/390 Q-Jet carb.
I had some forum members look at it on ebay. Turned out to be a restamp. Saved me $300.00 by asking first. Knowledge is good .
Marshal
The forum also saved my but in another post. I was interested in a 427/390 Q-Jet carb.
I had some forum members look at it on ebay. Turned out to be a restamp. Saved me $300.00 by asking first. Knowledge is good .
Marshal
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
I saw this book as well but more people have tended to recommend Ruggles. I'm sure both are enough to teach me LOTS about Q-J functions. Mainly, I need some recommendations regarding rebuilding and tuning these carbs without buying a ton of equipment. I have a vacuum guage, a timing light, and a couple of sorted through rebuild kits. Just want to know that if this car dies along the road I can pop the hood and have a chance to avoid calling for help.
Melting Slicks
Joined: May 2006
Posts: 2,590
Likes: 403
From: Nashville TN
St. Jude Donor '09
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
1. Doug Roe's book is invaluable for learning to work on Quadrajets and do basic performance modofications.
2. Cliff Ruggles is an expert on Q-jet performance, but his book can be a pandora's box for the average hot rodder. He goes into mods (idle circuit/ bypass air etc.) that are usually not needed or even desirable, with an emphasis that makes people feel they are a must. I'm sure a lot of good Q-jet cores have been trashed by people using his book.
3. Lars Grimsrud is THE MAN for Q-jets (and more). He does not have a book that I know of, but he has many articles he has written on Q-jets and will give them to anyone who asks FREE (try that with Cliff!). He specifically recommends tuning the carb from the stock configuration (NOT modifying the idle circuit/ Bapass air etc.).
Bottom line: Buy the Roe book and e-mail Lars. Study, then apply what you learn. Once you have expertice, get Cliff's book and gleen through it, using only what makes sense for the specific application.
God bless, Sensei
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Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
I am a carb tuner and here is my $.02 worth as far as books:
1. Doug Roe's book is invaluable for learning to work on Quadrajets and do basic performance modofications.
2. Cliff Ruggles is an expert on Q-jet performance, but his book can be a pandora's box for the average hot rodder. He goes into mods (idle circuit/ bypass air etc.) that are usually not needed or even desirable, with an emphasis that makes people feel they are a must. I'm sure a lot of good Q-jet cores have been trashed by people using his book.
3. Lars Grimsrud is THE MAN for Q-jets (and more). He does not have a book that I know of, but he has many articles he has written on Q-jets and will give them to anyone who asks FREE (try that with Cliff!). He specifically recommends tuning the carb from the stock configuration (NOT modifying the idle circuit/ Bapass air etc.).
Bottom line: Buy the Roe book and e-mail Lars. Study, then apply what you learn. Once you have expertice, get Cliff's book and gleen through it, using only what makes sense for the specific application.
God bless, Sensei
1. Doug Roe's book is invaluable for learning to work on Quadrajets and do basic performance modofications.
2. Cliff Ruggles is an expert on Q-jet performance, but his book can be a pandora's box for the average hot rodder. He goes into mods (idle circuit/ bypass air etc.) that are usually not needed or even desirable, with an emphasis that makes people feel they are a must. I'm sure a lot of good Q-jet cores have been trashed by people using his book.
3. Lars Grimsrud is THE MAN for Q-jets (and more). He does not have a book that I know of, but he has many articles he has written on Q-jets and will give them to anyone who asks FREE (try that with Cliff!). He specifically recommends tuning the carb from the stock configuration (NOT modifying the idle circuit/ Bapass air etc.).
Bottom line: Buy the Roe book and e-mail Lars. Study, then apply what you learn. Once you have expertice, get Cliff's book and gleen through it, using only what makes sense for the specific application.
God bless, Sensei
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,117
From: Crossville TN
The only other perspective that I would offer is that all of those fellows (plus many others) have knowledge, experience and advice that is of benefit to those wanting to work on Q-Jets. Also, none of them is perfect and their perspectives are all a bit different.
I choose to have reference material from all of them and will use whatever is needed to get the job done. To pick one "guru" out of the group is merely wasting 2/3 of the useful information on Q-Jet repair/rebuild/modification. Just my .02....
I choose to have reference material from all of them and will use whatever is needed to get the job done. To pick one "guru" out of the group is merely wasting 2/3 of the useful information on Q-Jet repair/rebuild/modification. Just my .02....
Melting Slicks
Joined: Jul 2006
Posts: 2,288
Likes: 489
From: Salmon Arm, BC
"I choose to have reference material from all of them and will use whatever is needed to get the job done. To pick one "guru" out of the group is merely wasting 2/3 of the useful information on Q-Jet repair/rebuild/modification. Just my .02....[/QUOTE]"
DING DING DING.....this is the best answer
DING DING DING.....this is the best answer
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
God bless, Sensei
Last edited by a1sensei; Oct 14, 2011 at 01:28 PM.
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
I agree
Well put. When I first posted I had already ordered the Ruggles book. Having read it I can now confirm that it is not a book for beginners. Start with a different book if you are looking to understand, overhaul, and tune your carb. The book doesn't even outline these topics much. It just briefly touches on the anatomy then dives into how to modify it for performance applications. It may be a great book for advanced users but I still don't know enough about setting up a stock QJ to know if I want to drill, tap, and saw my current carb!
Racer
Joined: Oct 2011
Posts: 318
Likes: 3
From: NP Nebraska
I need help adjusting the choke and warm idle. When my car has been run for about 15 minutes the primary throttle plate is wide open. The car idles smoother when I close it about half way. It will die if I try to pull the vacuum advance to the distributor to make adjustments. It is almost like it still needs choked to idle smoothly. How do I adjust this?
Safety Car
Joined: Oct 2000
Posts: 3,593
Likes: 103
From: Southern Indiana
If you pay $300 for a quadrajunk, new or not your ****** in the head in the first place, but its your money to waste so thats not the issue.
Heres what you do.
Buy a book and sit down one sunny Saturday afternoon and read it and mark the pages you might need.
Then round up the quads numbers and run down to a parts store and get a kit.
Then order some aftermarket parts and wait another week for them to come in.
Start the rebuild, by cleaning with carb cleaner and a brush, rag what ever. get it back together, and install on the car and take an afternoon and adjust, bend, take apart and adjust the float a couple of times.
Then test drive several times and a few days and then see what you got and if you like it.
Come back on this site and ask some more questions and go back to step one.
It only has to satisfy you.
By all means keep your quad and live with it.
Heres what you do.
Buy a book and sit down one sunny Saturday afternoon and read it and mark the pages you might need.
Then round up the quads numbers and run down to a parts store and get a kit.
Then order some aftermarket parts and wait another week for them to come in.
Start the rebuild, by cleaning with carb cleaner and a brush, rag what ever. get it back together, and install on the car and take an afternoon and adjust, bend, take apart and adjust the float a couple of times.
Then test drive several times and a few days and then see what you got and if you like it.
Come back on this site and ask some more questions and go back to step one.
It only has to satisfy you.
By all means keep your quad and live with it.
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
Lars has the best Q-jet choke set up proceedure out there. E mail him and ask for it (if you don't know his e-mail, PM me and I will give it to you). It is fast, simple and works.
God bless, Sensei
God bless, Sensei
