In severe enough cases the baseplate can even crack. A soft-bristle brush helps with really stubborn deposits and corrosion. Take pictures of every hose, with the label clearly marked and showing in the images. When it is present, this port can be used for the power brake booster. Becoming familiar with the carburetor If you have never dealt with a carburetor in your life, it is important to familiarize yourself with the various components.
Working with a unit that is up to par, we can make metering and calibration changes to get the desired and predicted results. Rebuilding carburetors this way ensures the core is not only in good condition and can be restored or rebuilt, but also ensures quality control can be monitored. With the correct modifications in the right places, the Quadrajet has no trouble being up to the task of powering your new engine combination. The Teardown Process Armed with my new information, I set about removing the carb from the intake manifold. The carburetor should be placed on a wooden spacer or other suitable fixture, so that any downward pressure applied during disassembly is not transmitted to the throttle shafts.
Keep in mind that only very small changes are necessary to see big gains in part-throttle feel. There is also a dwell adjustment once the carb is back on the car, using this same idle bypass valve. Murphy grinds the tip of the nipple to expose the restrictor located inside and then drills this restrictor to 0. Several companies offer solutions designed for this purpose. Thread offers information on power piston springs in relation to tuning a Rochester Quadrajet.
One company that is proving the carburetor — especially the Quadrajet — is still viable, is Each carburetor is inspected and assembled by one technician. An example of how to organize photos into helpful folders on the computer. All other components are cleaned, tested or rebuilt to meet O. The springs vary in length, coils per inch, and wire diameter 0. Wow, did that ever make a difference! I'll find some books on carb rebuilds and look for that quadrajet book. The test is to hold the baseplate up to a light source to see minimum light around the butterflies with the throttle closed against the idle-speed screw. Sure, it has more moving parts than any other carburetor, but that just lends validity to its adjustability.
Murphy says this idle air bypass valve is the proper way to adjust the carb for idle quality, not with the idle-mixture screws. Old ice cube trays can also be used. Organize your tools for easy access. It starts with the unit being disassembled, cleaned, and then subjected to a rigorous inspection process. Some have two orifices like on the left right tab would be where the circle is. Most Quadrajets have experienced some wear through years of use and countless heating and cooling cycles in the engine compartment.
Once on the workbench, the Quadrajet caburetor rebuild quickly started, hence our carb was disassembled within 15 minutes and the parts soaking in cleaning solution. Quick cropping, sharpening and brightening of photos will turn many mediocre shots into useful images. Everyone has their favorites: Holley, Carter, Quadrajet, Edelbrock and more. I must reiterate that going into this project, I knew nothing about carburetors or how they worked. The use of latex gloves and a full-sleeved shirt is highly recommended when working with this chemical.
All bolts and linkage parts are zinc plated. You can do this either as you are taking pictures or when you upload them to your computer. Another highly reviewed title is by Doug Roe. Most were built by the Rochester Division of General Motors, but some were also made by Carter. Make sure to keep the camera fully charged and as often as possible. If something doesn't match up, return it for the right part before beginning re-assembly. This is fine for most applications and makes sure that it does not require turning the mixture screws out four, five, or even six turns to get enough idle fuel to the engine.
Then make like a boy scout starting a fire or like you're lapping a valve. If there is enough length before the bend, the 90 degree can be cut off in order to reach the orifice. The amount of bypass air to use varies greatly for different applications. Care must be taken to protect the skin and eyes, and provide proper ventilation. It is useful for testing out all linkages before re-installation. Become familiar with the camera you have and use it to photograph everything, from every angle, every step of the way. The image to the right shows three different types of power piston.
The completed rebuilt carb looking much better in the engine bay. Basically if it idles good and the idle is steady even when the throttle shaft is moved fore and aft, it's good to go. Modifications to the different systems within the carburetor now become mandatory if one is to extract the full performance potential from the engine in all areas. In the future, as time allows for updates, the article will cite sections and passages from related books to help the reader follow along with ease. These kits include more parts than found in over-the-counter kits and are well worth the additional expense. Unfortunately, trying the carb on your running engine is about the only way you can know for sure, unless the desired orifice sizes are known ahead of time. Fortunately if need be, the lead can be fairly easily removed, or drilled to give bypass air.