More Quadrajet tuning, some things! Part one in this saga on Sept 13, 2010
The car has a slight stumble and surge at a light throttle cruise at about 55 to 60 MPH. By swapping out the .050 metering rods to .048 units, the stumble and driveability concerns are now gone. Going richer would mean worse fuel mileage one may think? No! Now that the mixture is right, LESS throttle opening is needed now, which means higher vacuum, and this way the metering rods will block off the correct amount of fuel, and in the proper timing and percentages, so the car runs much smoother. As stated many times, patience and reading up on, and understanding how these intricate carburetors work will help out very much! Enjoy!
More Quadrajet tuning, some things! Part two in this Saga Sept 13, 2010
With the camera sitting on the oil filler cap a few more things to show how
a metering rod system works on a carburetor. The car has a slight stumble
and surge at a light throttle cruise at about 55 to 60 MPH. By swapping
out the .050 metering rods to .048 units, the stumble and driveability
concerns are now gone. Going richer would mean worse fuel mileage one may
think? No! Now that the mixture is right, LESS throttle opening is needed
now, which means higher vacuum, and this way the metering rods will block
off the correct amount of fuel, and in the proper timing and percentages,
so the car runs much smoother. As stated many times, patience and reading
up on, and understanding how these intricate carburetors work will help out
very much! Enjoy!
The last thing to be looked at on the wagon, but really, no old car project
is ever done, things keep being played with and adjusted. This is a
correct Rochester Quadrajet 4-barrel carburetor I got some time ago, and
has been renewed with new seals. The bushings and other hard parts were in
good repair, so with the new seals. T o note, I called out the first three
serial numbers as being "701" when in fact it starts with "704" . When
building up a Rochester, one has to understand they can't just throw parts
into it, they may be unhappy with the results. They should also be ready
to have to change a jet here, a metering rod there, a spring or two after
the unit is on to get the car running perfectly. The Quadrajet is a sweet
carburetor, once you understand it a bit. As I am doing. It is running
well, but will need a bit more tuning in the way of a stiffer primary
metering rod return spring. Other then that, the car has more bottom and
top end power, mid range is the same, but the bonus is, fuel mileage has
picked up, the leaky bowl of the old unit is gone!
Replacing an HEI Coil & Quadrajet Comments (Not a "How-to")
The '77 Olds 350 suddenly developed a pretty nasty miss under load, which
slowly worsened to a miss at idle too. If you got close to the distributor
with the engine running, you could hear the coil arcing all over the place!
The Delta is equipped with the usual GM HEI distributor.
Rochester Quadrajet, the results!
Two mishaps, the first shown here, the choke coil I got was wound
backwards, it made the choke butterfly wind up TIGHTER as the engine warmed
up. I swapped on the one from the old carburetor fast enough, the second
mishap made me feel like a crud and what did I mess up later that evening.
The car would not start leaving the Etobicoke -Queensway show. It was not
getting gas. We got it running by priming the carburetor, and boy, was I
ticked at myself. In the end it was not my fault it looks like. The new
accelerator pump umbrella and rod was a very poor and frail design, the
umbrella came detached and stayed at the bottom of the of the pump well,
and was a distressed mess. The maker will get a note from me. The upshot?
The old assembly went in, all is perfectly fine, the slight tip-in
hesitation is gone now too. Stupid lack of pride it seems these days
making parts for even simple things like an old carburetor.
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.
first tutorial ever take it easy on me. i didnt have the luxury of a vacuum
gauge around so i did a general way of tuning a carb by ear. If u want a
more perfect tune i suggest you use a vacuum gauge and or take it to a
Auto Repair & Maintenance : How to Adjust Carburetors
Idle speed and idle mixture are the two most common adjustments made to
carburetors, and these adjustments start by warming up the vehicle to full
engine-operating temperature. Find out how to perform a lean-drop
adjustment with help from an ASE-certified master automobile technician in
this free video on carburetors.
Expert: Clark Mason
Bio: Clark Mason is an ASE-certified master automobile technician.
Filmmaker: Christian Munoz-Donoso