Rebuilding my own carb.

[Ajillag]

Decided to rebuild my own carb this weekend. Would any one be kind enough to tell me all the tools and materials I'll need. I bought the kit from autozone already. I'm a lil nervous but confident I can do it properly. All tips and advice is appreciated. I'm just trying to get a much life out of her as I can. Plan on replacing all hoses, sensors and gaskets. Replacing the valve covers and giving the motor a good cleaning. Need her to get me through the winter......hopefully

[2dooreighty5]

be sure to sort everything into categories which you will remember....
i used plastic bags and labeled when i rebuilt mine...

I sugest taking photos of stuff as it comes off so that u can get everything back to where it needs to be...

as far as tools i did mine with your basic set of screw drivers and ratchets but you do need some more specific ones for adjusting the jets and some other key components...

im sure someone more knowledgeable on here will help u with that...but take your time forsure dont rush it

[Ajillag]

Ok thanx

[MagicRat]

A couple of spray cans of carb cleaner, and a source of compressed air.

Also a new fuel filter, if your kit does not have one. Most kits don't, in my experience.

The Q-jets (and other Rochester carbs, too, I think) have a ridiculously small fuel filter in the carb at the fuel inlet, which can only hold a thimble-full of dirt.

[j cAT]

Originally Posted by Ajillag

Decided to rebuild my own carb this weekend. Would any one be kind enough to tell me all the tools and materials I'll need. I bought the kit from autozone already. I'm a lil nervous but confident I can do it properly. All tips and advice is appreciated. I'm just trying to get a much life out of her as I can. Plan on replacing all hoses, sensors and gaskets. Replacing the valve covers and giving the motor a good cleaning. Need her to get me through the winter......hopefully

with the questions you have asked here I strongly recommend you have this done by a repair shop that is qualified to rebuild this carb. not any auto repair shop.

also by having the GM part number on the carb get the many spec adjustments needed so that this is set up correctly.

this work is not for persons with no experience and/or the proper tools.

what could happen if you just do it ?

engine could go up in flames .

[Ajillag]

Thanx j cat. u dont have to tell me twice. I was looking forward to doing the task myself tho. Oh well

[Blue Bowtie]

Before starting the rebuild, read the complete instructions in the carb kit first so you know exactly what will be involved. If you read about the necessary adjustments after installing the rebuilt carb, you may want to perform those adjustments first. That alone may solve many or all of the operational issues you are experiencing, saving you from a complete rebuild. It would also be very good practice since you would have to do it all regardless once the carb is rebuilt.

There a a few special tools needed to do this properly, including a couple sizes of double-D sockets, a dwell meter (or duty-cycle meter), and it would be easier to use a straightedge and caliper to set the float drop and level instead of using the paper gauge provided with the rebuild kit. Feeler gauges will be handy to have if you don't have a wire gauge set. You will also need the correct size flare nut wrenches to remove the fuel line and possible the brake booster vacuum line. A small punch or pick will be needed to remove some Welch plugs for adjusting the rebuilt carb. A voltmeter will be needed to adjust the TPS. You will also need a tachometer and a timing light.

As for supplies, it will be good to have some fuel resistant epoxy on hand, anti-seize compound to apply to all the fasteners on assembly, and penetrating oil for removal of some of the stubborn fasteners and the throttle plate screws.





FLOAT CHECK

1. Remove the air cleaner and cap any vacuum lines that were disconnected;
   
2. Unplug the Throttle Position Sensor and enrichment solenoid connectors;
   
3. Remove the choke pull-off actuator and linkage rod (25 & 28);
   
4. Remove the secondary metering rod cam follower (10) and metering rods (9);
   
5. Remove the choke lever screw and lever, and the linkage rod (29, 30, & 31);
   
6. Remove the air horn screws (5, 6, & 7) and the two front carburetor to intake bolts;
   
7. Carefully lift the air horn (1) off the carburetor body. As you do, pivot the air horn to allow the accelerator pump linkage rod to be removed from the top lever (3, 69);
   
8. Hold down the float hinge pin (57) and simultaneously hold the front end of the float (56) closed against the inlet needle and seat (55), to raise the float to its maximum position. Verify correct float level by measuring the rear edge of the float to the top of the carburetor body with no gasket in place. Gently bend the float tab to raise or lower this setting to the specification;
   
9. Replace the gasket and reassemble the carburetor, being careful to properly align the metering rods, pickup tubes, and TPS actuator plunger;
   
10. Reconnect the hoses and electrical connectors;

TPS ADJUSTMENT

1. Start engine and allow it to reach normal operating temperature;
   
2. Set engine timing at the specified RPM;
   
3. Set base idle speed with the A/C off and idle speed solenoid disconnected;
   
4. Turn off the engine;
   
5. Insert the probes of a digital voltmeter in terminals ‘B' and ‘C' on the TPS connector (center and bottom terminals). You may have to insert a paper clip or similar object into the rear of the connector to make contact;
   
6. Turn on the ignition but do not start the engine. Read the voltage of the TPS. Remove the top plug (19) and adjust the TPS screw (18) to obtain a reading of 0.48VDC across the terminals.
   
   NOTE - If your meter probes are reversed, the reading will be -0.48VDC. The important factor is the number.
   
7. Replace the hole plug in the adjustment screw hole when the position is set;
   
8. Connect a dwell meter or oscilloscope probe to terminal ‘B' on the enrichment solenoid connector;
   
9. Start the engine and allow it to reach normal operating temperature. Start the engine and reset the base idle if necessary. The dwell meter reading should vary while this is occurring, or the oscilloscope square wave frequency (pulse length) should vary;
   
10. Set the parking brake, block the drive wheels, and place the transmission in DRIVE for an automatic car, NEUTRAL for a manual car;
    
11. The dwell meter reading should fluctuate between 10̊ and 50̊ on the 6 cylinder scale, the oscilloscope should indicate a 15-85% duty cycle. Adjust the idle air bleed valve screw (12) in 1/8th turn increments to obtain a dwell reading between 25̊-35̊. The optimum setting is 30̊ (50% duty cycle), so get as close to this as possible. Adjust the screw only a little at a time and allow the system to react between adjustments;
    
12. If the desired reading is not attainable through this method, the idle mixture screws will have to be adjusted (87). This will require removal of the carburetor and cutting the throttle body away around the steel plugs. Then reinstall and adjust the idle mixture screws evenly , then adjusting the idle air bleed screw as described above to obtain the correct readings.

[DeltaP]

Having that GM part number tag is sooo critical for correct parts and set up. Unless you've done alot of 'em have a specialist do it for ya. They made a ton of versions of that Quadra-leak!

[j cAT]

Originally Posted by DeltaP

Having that GM part number tag is sooo critical for correct parts and set up. Unless you've done alot of 'em have a specialist do it for ya. They made a ton of versions of that Quadra-leak!

if he is smart he will do as we have suggested and have an experienced shop with this carb do the work.

that carb number is not optional !