The Rochester Quadrajet has gotten a bad rap over the years, but it's actually an excellent carburetor once you understand how they work.
Often referred to as "Quadrabog" or "Quadrajunk", many of the issues these units suffer stem from neglect, or "modifications" that do more harm than good.
Being a spreadbore, air-valve secondary design, the Quadrajet is capable of flowing 750 or 800 cfm of airflow, eliminating the need to buy different carburetors when your set-up changes. In addition, the small primaries make for great drivability and fuel economy.
In this clip, I'll discuss theory of operation on the secondary side, since that's where most problems arise. So, leave your preconceived notions at the door and let's see what makes these carburetors tick.
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.
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.
How to adjust Quadrajet/Dualjet fast idle
Quadrajet/Dualjet Rochesters have a fast idle adjustment screw that is
separate from the base idle screw.Here's how to locate it.
NOTE THAT THE CHOKE ITSELF MUST BE WORKING IN ORDER FOR THE FAST IDLE TO
Most relaxing sound for men - Old-School American V8 Corvette C3 1979 (Stingray)
Includes Cold engine idle, warm idle and a bit of revving to about 4500
RPM. I decided to create this video since my Vette now sounds quite loud
thanks to the Cherrybomb glasspack Exhaust and removal of the catalyst. The Exhaust is basically stock. I think this is
one of the most relaxing sounds for men who are into cars and machines :)
Engine: 5.7 L (350 cid) V8 L-48
Transmission: Warner 4-Speed Manual
My Corvette is generally in very good condition and it has already been
restored once in USA some years before it arrived in our country. I got the
car in a state where the exterior + drivetrain were fine, but the interior
needed new carpet, some painting and several other components in order to
look great. I'm now pretty much done with the interior. The engine used to
have issues but those were mostly external (bad thermostat housing, bad
spark plug wires etc.). By now the engine is a pleasure to drive, but the
Rochester Quadrajet carburetor has hard time keeping the pre-selected idle
speed and sometimes wants to hold it higher, then lower. It might be also
some extra fuel leaking in from somewhere occasionally. There used to be
some vacuum leaks but I've taken care of them. Perhaps I will replace the
intake + carb with an Edelbrock setup for next driving season. The engine
compression has been measured recently and the results were perfect for all
NB! We will soon try to film the Vette from another car when driving on a
motorway. I'm hoping to get some good footage that way.
For more information and work history on my Corvette, Suburban and ex-Jeep
Grand Cherokee, please visit my blog at http://www.georgescarblog.com .