Quadrajet Problem Solving > Buy Quadrajet Parts, Quadrajet Kits, Service
jet and rod advise needed
REFORMULATED:
I have a 69 Grand Prix 428 all stock Q- jet Part 7028276/1717 that's running a bit lean. I recently installed a Cliff kit with HP accelerator pump, no problems. Has a very slight flat spot just off idle and plugs reveal lean condition, pings more than I would like at 9 BTC vacuum advance disconnected , no surprise with lousy modern CA fuel. I also own a 70 Formula 455 comp 268 cam 6x- heads approx 9.7 to 1 compression that Cliff did the entire Q-jet part 7040563 /563 that has 71 jets, 39 primary rods, and DA secondary rods. I don't know what other "magic" Cliff performed on it, but it works great. I installed it on my GP and boy it runs a lot better, was able to increase timing to 10 BTC connected the vac advance no pinging and way more responsive overall and no flat spot . My GP carb has no markings on the jets and rods so I have no clue where to start.Any advise would be most welcome.
Ethan1:
--- Quote from: REFORMULATED on November 27, 2013, 11:02:50 PM ---I have a 69 Grand Prix 428 all stock Q- jet Part 7028276/1717 that's running a bit lean. I recently installed a Cliff kit with HP accelerator pump, no problems. Has a very slight flat spot just off idle and plugs reveal lean condition, pings more than I would like at 9 BTC vacuum advance disconnected , no surprise with lousy modern CA fuel. I also own a 70 Formula 455 comp 268 cam 6x- heads approx 9.7 to 1 compression that Cliff did the entire Q-jet part 7040563 /563 that has 71 jets, 39 primary rods, and DA secondary rods. I don't know what other "magic" Cliff performed on it, but it works great. I installed it on my GP and boy it runs a lot better, was able to increase timing to 10 BTC connected the vac advance no pinging and way more responsive overall and no flat spot . My GP carb has no markings on the jets and rods so I have no clue where to start.Any advise would be most welcome.
--- End quote ---
Stock jets and rods for carb 7028276 is, .073" Jets, Primary Metering Rods 41, Secondary Hanger K and Secondary Metering Rods BE.
Cliff Ruggles:
You will find some control of idle/off idle fuel delivery via the screw under the triangular cover. Might want to check the PP arms to verify they are exactly even, and rods not too low in the jets. I just finished a 7028276 carb yesterday, and it required bending the hanger arms up slightly, and seating the screw under the cover to get the A/F where it needed to be......Cliff
REFORMULATED:
Thank you Cliff, Checked the PP/Rods and sure enough one was slightly lower, then backed the idle/off idle adjustment screw off a about 1/2 Turn from seated and the flat spot is completely gone and it idles very smooth. My 428 is very responsive thanks to your kit, HP pump and most of all guidance. I would like to richen the secondary circuit slightly to reduce slight pinging when they open, primary is fine. What rods would I purchase?
Your tireless assistance to others is truly commendable and seldom seen anymore. I will always buy your kits and parts from here on out and recommend others to do the same.
Cliff Ruggles:
What metering rods are you using in it now?....Cliff
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