I love the quadrant. I had one on my 308 Holden (Australian car) and it ran so well. I had mine tuned and set up. Awesome throttle response for cruising around town on the primaries and the sound when I’d push it and the secondaries opened.
Know a guy who bought a brand new 69 corvette 427/390 horse. Came with a Quadrajet. On the way home from Porter Chevrolet in Delaware he said "it will run clean out of numbers" it was a 4 speed and pretty sure it had 336 rear gears. Quadrajets work just fine!!!!
I would love to have a Quadrajet builder i know help me fix mine but it doesn’t seem to want to do what it needs to. Going to try a quick fuel 680 really quick to see if it is indeed my botched rebuild. Also one of my dreams is to run a big block chrome bumper c3 at laguna seca.
I own a 1978 Chevy c10 and I just put a kit in my quadrajet and I'm having the same problem my secondarys are getting suck on the bottom plate I just shave the butterfly and it works great.
On the rochester i set up a vacuum guage and achieved 17 inches of vac with if i remember right 5 turns on left and 4,5 on right screw, one is idle speed screw and the other is fuel mixture screw, dont ask me which its been a while since i adjusted it. the rochester is a good carb, i've had zero issues with it other than putting a new float, gaskets and needle in when i bought the truck bc it had sat for a long while in the woods. since i tuned it up its been great. sbc 305 w/ 357,000 mi and still going.
Something I always used was the tip that comes with gear oil.It usually screws on a drink bottle.Easy way to fill the float bowl through the vent tube.hardly any fuel spill.
Q jets are great carbs, but take a fair amount of research to really understand them. Once you get them right they're the best factory carb that GM ever made.....and they made a ton of them.
You need to learn about qjets. The secondaries can only open when the choke is completely off. You need to adjust the fuel ratio, and then the idle, then you can test the secondaries. They should be locked closed at idle, expecially cold.
I have read the Q-jet book multiple times and there are certain styles of chokes that people will completely get rid of. The one I had was one of them. I have an electric choke I intend to use when I get back to that point
I actually have 2 qjets on my table right now. One has the choke removed, and one doesn't. You have a choke that appears to be working fine. Your secondaries won't open because your engine is idling. You're fighting against them being held closed by vacuum, as the original design is supposed to do. When you try to open them, the engine dies from too much air. You need to adjust your idle mixture screws so the idle is the highest, then get your idle screw set. After that, you should be able to see if your secondaries work. A carb works when you floor it by: first accelerator pump squirts gas, then primary and secondary throttle plates open, then vacuum is relieved on the secondary top plates so they can open, then the engine is pulling as much air and fuel as it can. You need to snap open the throttle and keep it there for a couple seconds to see the secondaries work.
When I was driving it back from Oregon in my first video on this truck the secondaries weren’t opening then either. They may have just been getting stuck though I suppose.
Next time you are at the parts house, buy a bottle of Bottle Jack Oil then go home and replace the oil in your bottle jack. Save the bottle with the filler tip and use it to put gas in so you can fill the float bowl and also a little squirt down the barrels. A lot easier than trying to pour from a pop bottle. Everyone loves a Fat Motored C10.
Opening the secondary air flaps manually on a vacuum secondary carb is the same as introducing a "vacuum leak", and leans the mixture out. They only function under FULL THROTTLE!
Hey dude you probably already know what the problem was about your secondarys not opening it because the chock has to be totally open to the secondarys and it will scream.
Thank you yeah i didnt end up getting the right choke setup for it and eventually just put on a newer carb, i will probably revisit the quadrajet when i get another project that needs it
Wow who said gently seat them and leave it lol gently seat them and back out 3 turns is a good starting place it will start and run usually then go from there what carb is that I've not seen a q jet w that square thing on the top front and what big block motor nice truck
May wanna properly adjust the mixture with vacuum gauge, then adjust idle screw if needed,,then check ignition timing with gun. 😅😅really easy when you know what your doing 😅😅😅
Your timing sounds kinda low once you get it idling good id take it down the road and advance the timing. Once you get it right you’ll have to reset the carb.
Yeah? I don't see myself using it or doing the rebuild it needs. I would love to see it go to a person who actually wants it. O think it's RAD but I don't think i will be keeping it for what I am planning.
