Getting the carb right the first time...
January 14th, 2011, 04:25 PM
#1
Got wood? I do! (an '89)
Thread Starter
Join Date: Nov 2010
Location: Southeast Michigan
Posts: 310
Getting the carb right the first time...
It has come down to this: my Angie needs a "new" carb, and it's looking like a $550-at-least kind of job. To say I want to get it right the first time is an understatement.
SO, I guess the first step is finding out exactly what I have now. Even though the 5-liter/307 was a pretty long-lived item the carbs were not, apparently, as there are TONS of different kinds/styles/whatever that aren't necessarily compatible even though they're all 4BBL Quadrajets.
Where are the numbers I need? If they're on the carb, is finding them as simple as removing the air cleaner housing and looking? Is there any kind of shopping-around I can do or do I have to replace it with exactly the same unit? [Seems like an aftermarket carb--at nearly the same price--would be good but will I have to redo everything else to use it?]
Then there's buying an already-rebuilt unit from a big-box-type auto store versus a professionally-rebuilt carb from specialist shops versus getting the original rebuilt by someone, etc.
I have never loved fuel injection more than I do now that I'm dealing with this issue. As with repairs to brakes, engines, suspension, etc., I subscribe to my patented "Someone Else to Blame" Rule*: If something goes south after the repair, I want someone else to blame for it so I don't have to go and re-spend the money to get it done right, as it should have originally been. [*Also known as the "Plumber" and "Roofer" rules.]
Oh, and then there are things that should be done at the same time as it's already apart, like the oxygen sensor, vacuum lines, etc., so the new carb has a fighting chance at running properly. Seems there's stuff you have to keep (one thing that says "AC" that sticks up through the bottom of the air cleaner housing) and stuff you NEED to replace. Ugh.
Something else: Nobody likes the carb I have now. It's "sealed", they say, so the kind of adjustments that MIGHT work to deal with my issues can't be made. I DO NOT WANT THAT. I want a carb that can be tweaked just-so as needed. Does that exist?
Anyhoo, as you can see, it's been on my mind for awhile now, though no amount of research I've done seems to arrive at the same answer. I just want my car to RUN WELL for a LONG time. Period. I want the carb to be like a water pump or an alternator: Here's the part, put it on, done.
Is that too much to ask?...
Drew
SO, I guess the first step is finding out exactly what I have now. Even though the 5-liter/307 was a pretty long-lived item the carbs were not, apparently, as there are TONS of different kinds/styles/whatever that aren't necessarily compatible even though they're all 4BBL Quadrajets.
Where are the numbers I need? If they're on the carb, is finding them as simple as removing the air cleaner housing and looking? Is there any kind of shopping-around I can do or do I have to replace it with exactly the same unit? [Seems like an aftermarket carb--at nearly the same price--would be good but will I have to redo everything else to use it?]
Then there's buying an already-rebuilt unit from a big-box-type auto store versus a professionally-rebuilt carb from specialist shops versus getting the original rebuilt by someone, etc.
I have never loved fuel injection more than I do now that I'm dealing with this issue. As with repairs to brakes, engines, suspension, etc., I subscribe to my patented "Someone Else to Blame" Rule*: If something goes south after the repair, I want someone else to blame for it so I don't have to go and re-spend the money to get it done right, as it should have originally been. [*Also known as the "Plumber" and "Roofer" rules.]
Oh, and then there are things that should be done at the same time as it's already apart, like the oxygen sensor, vacuum lines, etc., so the new carb has a fighting chance at running properly. Seems there's stuff you have to keep (one thing that says "AC" that sticks up through the bottom of the air cleaner housing) and stuff you NEED to replace. Ugh.
Something else: Nobody likes the carb I have now. It's "sealed", they say, so the kind of adjustments that MIGHT work to deal with my issues can't be made. I DO NOT WANT THAT. I want a carb that can be tweaked just-so as needed. Does that exist?
Anyhoo, as you can see, it's been on my mind for awhile now, though no amount of research I've done seems to arrive at the same answer. I just want my car to RUN WELL for a LONG time. Period. I want the carb to be like a water pump or an alternator: Here's the part, put it on, done.
Is that too much to ask?...
Drew
January 14th, 2011, 08:05 PM
#2
Moderator
Join Date: Sep 2006
Location: Medford, Oregon
Posts: 13,692
Hey Drew
I've only played with quadrajets from the 1960's and 70's so I don't know what kind of electronics yours has in it. That sounds like a lot of money though, so you might shop around a little more, maybe find someone who would rebuild the one you have.
On the older ones, and I suspect yours too, the number is stamped in the carb on the drivers side, toward the rear. The numbers run from down near the manifold and up toward the air cleaner. If you can't find it let me know and I'll get a photograph for you. John
I've only played with quadrajets from the 1960's and 70's so I don't know what kind of electronics yours has in it. That sounds like a lot of money though, so you might shop around a little more, maybe find someone who would rebuild the one you have.
On the older ones, and I suspect yours too, the number is stamped in the carb on the drivers side, toward the rear. The numbers run from down near the manifold and up toward the air cleaner. If you can't find it let me know and I'll get a photograph for you. John
January 15th, 2011, 07:16 AM
#3
Registered User
Join Date: Sep 2010
Location: Shorewood, Il.
Posts: 3,057
Back when I was paying with my '86 Grand Prix, [305 chev, computer carb] I almost ordered a carb from someone in California who said they tuned it to the car, not factory specs.
You shoud be able to find someone on the internet.
As far as your comparison to a water pump - ain't gonna happen - 1 moving part on the water pump [bearing], variable = coolant, vs 30 moving parts on the carb, with at least 7 variables = air, fuel, dirt, electric parts, voltage, fuel and throttle pressure!
Biggest problem I had was throttle shaft wear, but was in a position to get low mileage used ones cheap, luckily it was a standard 305 - they made a million of them!
You shoud be able to find someone on the internet.
As far as your comparison to a water pump - ain't gonna happen - 1 moving part on the water pump [bearing], variable = coolant, vs 30 moving parts on the carb, with at least 7 variables = air, fuel, dirt, electric parts, voltage, fuel and throttle pressure!
Biggest problem I had was throttle shaft wear, but was in a position to get low mileage used ones cheap, luckily it was a standard 305 - they made a million of them!
January 15th, 2011, 08:24 AM
#6
Registered User
Join Date: Feb 2008
Location: Plano, TX
Posts: 11,798
Rebuilding yours to factory spec by a COMPETENT shop is the way to do it right.
They can rebush the throttle shafts, too, if needed.
Search here for carb rebuilders - lots of threads. Many of the shops have great reputations.
You have the TPS and mixture control solenoids that might as well be done, too. You can get those from GM still I believe. Send 'em to rebuild along with the carb.
What are the problems you are having? Any shop that won't touch it because it is sealed just does not want to mess with it (cause they may know nothing about carbs!)
If you get yours rebuilt, do NOTHING to the rest of the car until you get the carb back on to compare how it runs.
Even with a 'perfect' rebuild, the mechanical state of the engine will require adjustments after installation. Use the methods in the factory service manual and all should go well.
They can rebush the throttle shafts, too, if needed.
Search here for carb rebuilders - lots of threads. Many of the shops have great reputations.
You have the TPS and mixture control solenoids that might as well be done, too. You can get those from GM still I believe. Send 'em to rebuild along with the carb.
What are the problems you are having? Any shop that won't touch it because it is sealed just does not want to mess with it (cause they may know nothing about carbs!)
If you get yours rebuilt, do NOTHING to the rest of the car until you get the carb back on to compare how it runs.
Even with a 'perfect' rebuild, the mechanical state of the engine will require adjustments after installation. Use the methods in the factory service manual and all should go well.
January 15th, 2011, 03:57 PM
#7
Hangin' out...
Join Date: Dec 2008
Location: Scottsdale, AZ
Posts: 608
Rebuilding yours to factory spec by a COMPETENT shop is the way to do it right.
They can rebush the throttle shafts, too, if needed.
Search here for carb rebuilders - lots of threads. Many of the shops have great reputations.
You have the TPS and mixture control solenoids that might as well be done, too. You can get those from GM still I believe. Send 'em to rebuild along with the carb.
What are the problems you are having? Any shop that won't touch it because it is sealed just does not want to mess with it (cause they may know nothing about carbs!)
If you get yours rebuilt, do NOTHING to the rest of the car until you get the carb back on to compare how it runs.
Even with a 'perfect' rebuild, the mechanical state of the engine will require adjustments after installation. Use the methods in the factory service manual and all should go well.
They can rebush the throttle shafts, too, if needed.
Search here for carb rebuilders - lots of threads. Many of the shops have great reputations.
You have the TPS and mixture control solenoids that might as well be done, too. You can get those from GM still I believe. Send 'em to rebuild along with the carb.
What are the problems you are having? Any shop that won't touch it because it is sealed just does not want to mess with it (cause they may know nothing about carbs!)
If you get yours rebuilt, do NOTHING to the rest of the car until you get the carb back on to compare how it runs.
Even with a 'perfect' rebuild, the mechanical state of the engine will require adjustments after installation. Use the methods in the factory service manual and all should go well.
I had my carb parts serviced by barker gang garage in Denver. They unwarped and repaired the castings, rebushed the throttle shafts, and shipped it back pretty quickly. I did the final cleaning, assembly, and adjustment. Dennis is a great guy to deal with. He can do a full rebuild, too. It will be less than $550, too.
http://www.quadrajetcarburetors.com/index.html
I've heard a lot of good things here about sparky's, but I don't know if they'll touch post-1980 unit. You may want to call them.
As far as the vacuum lines, go one at a time and take your time. It's really not that complicated. Take pictures. You're right in saying that they need to replaced to get the most out of the carb.
Seriously, don't remove anything. You have virtually no power to gain, and possibly some to lose in addition to time. If you want you car to go faster, don't invest in the 307. This is a very old subject around here.
It's a great workhorse, but your bang for the buck will be from a 350 or 403. It's a bolt-in and the computer shouldn't even notice as long as the cam isn't too radical. Get the 307 running as best as you can and drive it until it dies. Then replace it. The carb. number is located on the driver's side of the carb, near the rear. For a unit like yours, it should be something like 17088253. There's a ton of websites regarding Q-jet identification. Happy viewing and good luck!
http://www.recarbco.com/technical/rochester/qjet.html
http://www.4wheelnoffroad.com/qjetid.html
Thread
Thread Starter
Forum
Replies
Last Post
tannerblackart
The Newbie Forum
3
August 11th, 2014 06:41 AM
Slater442
The Newbie Forum
14
November 23rd, 2012 11:29 PM
