Quadrajet rebuild
10-18-2005, 08:06 PM
#1
Racer
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Quadrajet rebuild
How long does it normally take to rebuild a quadrajet? How long for a first timer?? I plan on rebuilding my quadrajet here in a few weeks. Thanks 
10-18-2005, 08:40 PM
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The first time I did it, I worked REALLY slowly. It took me a about 4 hours, but I didn't loose any parts and it ran perfectly after. (An experienced person could do it in A LOT less time.)
Make yourself a stand using a piece of wood and 4 long carriage bolts. Put the bolts through the board and put nuts half way down the bolts. Mount the carb on the four bolts so that it sits on the nuts half way down the bolts. Make the carb sit on the bolts as it would be on the manifold, but no need to bolt it down. The carb should sit a few inches off the board so that the butterfly on the undersde of the carb can move freely. This will make rebuilding much easier. Get a copy of Doug Roe's book on Rochester Carbs. It shows the whole process.
Make yourself a stand using a piece of wood and 4 long carriage bolts. Put the bolts through the board and put nuts half way down the bolts. Mount the carb on the four bolts so that it sits on the nuts half way down the bolts. Make the carb sit on the bolts as it would be on the manifold, but no need to bolt it down. The carb should sit a few inches off the board so that the butterfly on the undersde of the carb can move freely. This will make rebuilding much easier. Get a copy of Doug Roe's book on Rochester Carbs. It shows the whole process.
10-19-2005, 12:58 AM
#4
Drifting
Before you get too far into it, check for play in the primary and secondary throttle shafts. Excessive play could mean an incurable vacuum leak which can only be fixed through rebushing, which may be beyond a novices capability. Otherwise, just take your time. A good idea which helped me the first time through, is to take a bunch of digital pictures as you dissemnble, especially with all the little rods and linkages.
10-19-2005, 06:44 AM
#5
Safety Car
It takes me about a half-hour to completely strip and kit a Q-Jet...but that's only if the carb is otherwise clean and just needs a kit. If the carb is really nasty and crudded up, it takes a couple of days due to the soak time in the carb cleaner bucket. If the carb is functioning really bad, I'd plan on a good, long soak.
10-19-2005, 08:58 AM
#6
Drifting
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I rebuilt my first q-jet in about an hour or so. Used a couple of old cookie sheets to lay out the parts. There isn't as many parts as I expected. Went relatively easy, worked great when I put it back on the 68 chevrolet truck I took it off of. This q-jet in particular was a 1970 model.
10-19-2005, 09:36 AM
#7
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...and if you have any problems or run across anything you have questions about, you can give me a call - I'll be more than glad to walk you through it over the phone. I can send you my ph# in an e-mail.
BTW - The loose throttle shaft/vacuum leak thing is grossly over-rated. The Q-Jets had sloppy throttle shafts when they were brand new. The Q-Jets leak more air down through the power piston bore than they do through the throttle shafts. Combine this with the massive "leak" from your PCV, and the slight leakage through the shaft bores is irrelevant. Don't worry about the shafts unless they're so loose that the throttle blades don't close consistently.
BTW - The loose throttle shaft/vacuum leak thing is grossly over-rated. The Q-Jets had sloppy throttle shafts when they were brand new. The Q-Jets leak more air down through the power piston bore than they do through the throttle shafts. Combine this with the massive "leak" from your PCV, and the slight leakage through the shaft bores is irrelevant. Don't worry about the shafts unless they're so loose that the throttle blades don't close consistently.
10-19-2005, 01:59 PM
#8
Le Mans Master
Originally Posted by lowbuck72
Before you get too far into it, check for play in the primary and secondary throttle shafts. Excessive play could mean an incurable vacuum leak which can only be fixed through rebushing, which may be beyond a novices capability. Otherwise, just take your time. A good idea which helped me the first time through, is to take a bunch of digital pictures as you dissemnble, especially with all the little rods and linkages.
Put "leaky throttle shaft" in google and see what comes up.
10-19-2005, 02:47 PM
#9
Racer
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Thanks to everyone for the tips!! I was expecting this to be a nightmare, but I feel more comfortable now. Lars, if you want to e-mail me at 78vette@gmail.com with your phone # I'd appreciate it. I probably won't get to this for a few weeks. Thanks again!!
10-19-2005, 04:05 PM
#10
Safety Car
Mine took approximately 1 week to rebuild.
1) Step 1 remove carb from manifold.
2) find a box slightly larger than the carb.
3) Put carb in Box and Ship to Lars in Denver.
4) Drink beer while waiting for carb to return.
5) When carb arrives back one week later, reverse step one.
Now your carb is completely rebuilt.
1) Step 1 remove carb from manifold.
2) find a box slightly larger than the carb.
3) Put carb in Box and Ship to Lars in Denver.
4) Drink beer while waiting for carb to return.
5) When carb arrives back one week later, reverse step one.
Now your carb is completely rebuilt.
10-20-2005, 08:40 AM
#11
Melting Slicks
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St. Jude Contributor
I wouldn't think you'd need a book for a simple kit-install type rebuild. The kits come with a blow-up diagram and basic adjustment instructions. As long as you go by the numbers, you ought to be just fine--it's not hard.
One suggestion: instead of a cookie sheet, I use a medium sized terry cloth towel to put the parts on as I take them off. That way, you can lay them down on the towel in the order you take them off, left to right & top to bottom. The knap of the towel holds the tiny parts so they don't go anywhere (amazing how easy it is to misplace one of those little springs), and then you can just reverse the order to reinstall.
JB
One suggestion: instead of a cookie sheet, I use a medium sized terry cloth towel to put the parts on as I take them off. That way, you can lay them down on the towel in the order you take them off, left to right & top to bottom. The knap of the towel holds the tiny parts so they don't go anywhere (amazing how easy it is to misplace one of those little springs), and then you can just reverse the order to reinstall.
JB
10-20-2005, 02:35 PM
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St. Jude Donor '11, '16-'17
Originally Posted by JB
I wouldn't think you'd need a book for a simple kit-install type rebuild.
10-20-2005, 03:58 PM
#14
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St. Jude Donor '05-'09-'10
simple for some...
Originally Posted by The_Dude
I think it depends on your level of experience. I found the book quite useful. It helped me understand the basic workings of a quadrajet, has better diagrams, and also gave the order of disassembly and reassembly.
10-20-2005, 05:30 PM
#15
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Originally Posted by Stewart's74
Mine took approximately 1 week to rebuild.
1) Step 1 remove carb from manifold.
2) find a box slightly larger than the carb.
3) Put carb in Box and Ship to Lars in Denver.
4) Drink beer while waiting for carb to return.
5) When carb arrives back one week later, reverse step one.
Now your carb is completely rebuilt.
1) Step 1 remove carb from manifold.
2) find a box slightly larger than the carb.
3) Put carb in Box and Ship to Lars in Denver.
4) Drink beer while waiting for carb to return.
5) When carb arrives back one week later, reverse step one.
Now your carb is completely rebuilt.
I thought about that!!
But I would really like to learn how to do it myself.
10-20-2005, 05:35 PM
#16
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St. Jude Donor '11, '16-'17
I did an old Cadillac quadrajet to learn how to do it, then I had Lars do my Corvette carburetor. I got the Cadillac running ok, but not the same level that my Corvette runs. It's nice to get it back from Lars, bolt it on, and not have to touch any of the adjustments.
10-20-2005, 08:50 PM
#17
Drifting
Just a question while we're on carb rebuilding. Nowadays what do you use to soak the parts in. I have a 5 gallon Berryman Chem Dip that's about half full and 20 years old. It doesn't work as good as it used to, boy, when I pop off the lid that smell takes me back...
10-20-2005, 11:01 PM
#18
Team Owner
Originally Posted by lars
...and if you have any problems or run across anything you have questions about, you can give me a call - I'll be more than glad to walk you through it over the phone. I can send you my ph# in an e-mail.
BTW - The loose throttle shaft/vacuum leak thing is grossly over-rated. The Q-Jets had sloppy throttle shafts when they were brand new. The Q-Jets leak more air down through the power piston bore than they do through the throttle shafts. Combine this with the massive "leak" from your PCV, and the slight leakage through the shaft bores is irrelevant. Don't worry about the shafts unless they're so loose that the throttle blades don't close consistently.
BTW - The loose throttle shaft/vacuum leak thing is grossly over-rated. The Q-Jets had sloppy throttle shafts when they were brand new. The Q-Jets leak more air down through the power piston bore than they do through the throttle shafts. Combine this with the massive "leak" from your PCV, and the slight leakage through the shaft bores is irrelevant. Don't worry about the shafts unless they're so loose that the throttle blades don't close consistently.
10-20-2005, 11:02 PM
#19
Team Owner
Originally Posted by gerry72
It takes me about a half-hour to completely strip and kit a Q-Jet...but that's only if the carb is otherwise clean and just needs a kit. If the carb is really nasty and crudded up, it takes a couple of days due to the soak time in the carb cleaner bucket. If the carb is functioning really bad, I'd plan on a good, long soak.
