How to debog your Quadrajet part 3
In the first two videos we looked at operational theory of the Quadrajet. In this episode we'll explore a couple mistakes the home mechanic often makes in an effort to improve the performance of this unit.
How to de-bog your Quadrajet part 1
Sorry guys, I got the videos a bit out of order.
The Rochester Quadrajet has gotten a bad rap over the years, often called a Quadrabog or Quadrajunk.
In fact, this is a great multipurpose carbureter once you understand how they work and what not to do to them.
In this clip I introduce you to the Quadrajet and begin explaining the theory of operation of these units.
Identifying vacuum ports, late-style Quadrajet
I always see a lot of questions about what various vacuum ports do on a Quadrajet.
Here's a general guide that will point you in the right direction. Remember that there were many different Qjets over the years and vacuum port locations and number will vary. This video is representative of 1975-90 carbs.
750 vs. 800cfm Rochester Quadrajets-how to tell them apart
There exists a ton of misinformation regarding the actual airflow capacity of the Rochester Quadrajet. Not many people know how many variations there are or how to tell them apart.
Here is a simple video explaining how to identify each size based on casting design. I will cover the "cfm-limited" carbs in a separate video.
Quadrajet air leak fix and warped air horn repair tutorial.
How to identify a Quadrajet with a warped air horn without diss assembly or running it on a car. These tips would have saved me time and money which is why I made this video. I also discus how to repair a warped air horn and prevent your air horn from warping in the first place. If you have a whistling noise just off idle then you got some work to do. You will never get your engine tuned right, your cold start performing or decent fuel economy unless your four barrel carburetor is just right. Special thanks to Cliff Ruggles for his book Rochester Quadrajet carburetors and to my brother Adrian who spent hours on tuning and fitting.
See this video for description of the technique I used to straighten a warped air horn.
how to minimize engine bog with a Quadrajet carb
this is to minimize engine bog when the pedal is to the metal. do not over tighten, very small spring...you want to try 1/4 turns or 1/2...q-jets are good if tuned properly. also when you are tightening screw it will have tension on it so keep the screwdriver firm. 1986 gmc sierra single straightpipe to cherrybomb. you will need a small flathead screwdriver and a 3/32 allen key. be sure not to tighten to much or else your vacuum secondary flaps wont open.