what could the problem be for this? its not a cc carb, someone swapped it outta there before i bought it and its just a normal q-jet.

 

how do you know they are not opening?

the secondary air valves dont normally draw enough vacuum to open while sitting in park or neutral.

 

i have had lots of problems with quadrajunk's secondaries, they will only open under lots of load (high vaccume) and dont do anything till above 3000rpm which the vacume is low again...

 

the carb is a good carb, one just needs to learn how to tune them I have seen 11 second and 10 second cars in the quarter use them. Find yourself a great carb guy who is willing to teach you how to tune the carb. also there is books out there to help you. I do know that on a holly vac seconday you replace a spring for opening the secondaies. just food for thought

later and

GB

rick

 

just so ya know.....Q jets secondarys do not work on vacuum
Either hi or low. They work on airflow. Engine air flow.
When the engine is reving up while at WOT the sec air door will open as the engine requires more air. The air door has a little vacuum delay pot connected thru linkage that delays the air door from opening for a split second so the car does not bog. The air door spring tension is adjustable. It sets the rate of opening. All the linkage on the side of the carb has to be connected and functioning for the secondaries to work right ( choke, vacuum brake delay pot, choke pull off pot etc etc) Lots of people like to yank off this and that thinking they are carburator engineers and can make it better.

The air door does not open just by winging the throttle open in neutral and reving the engine. ( the delay pot prevents this). the door will open as the motor needs more air under load as the rpms come up. A adjustable spring controls the rate of opening. The vacuum controled delay pot/choke pull off diapharm controls the amount of door opening delay when you punch the throttle. Yes the engine does not need the extra secondary airflow till near 3000rpm. (especially on a stock motor) Different pots have different sized holes. If you have low rear gears and a stock stall converter don;t play with the hole size. Just make sure all the choke/secondary linkage is hooked up right and fuctioning and adjust the air door tension.
If you have a high rear gear ratio like 4.10's and a very high stall converter (3000+rpm) you can make the air door react faster by drilling the vacuum delay pot's restriction hole larger. If you make the door react too fast the car will bog.

 

the easy way to make sure your back 2 are opening is:

go for a spin, WOT test. time it or something.

then use a twist tie, or the like, and use the lockout tang to lockout your secondaries. Then do the same test, you'll probably notice the performance is pretty dismal.
ergo, your secondary's were opening (unless performance is the same, then yea, report back and we can tell you what to check)

Quadrajets rock BTW.

 

The #1 offender when a QJet's secondaries aren't opening (if that is truly the case) is that the choke isn't getting open fully. It might seem very odd the two systems affect eachother, but there is a little "arm" over on the pass. side of the carb that locks out the secondary throttle shaft from opening unless the choke is FULLY open. A shot or mis-adjusted choke element can be at fault, as can the 12V electrical connection that heats the choke element (the wire going to the round, black thing on the pass. side off the carb).

Beyond that it's very unusual for QJet secondarys not to open unless there's physical binding in the linkage somewhere or the vacuum canister on the pass. side of the carb has frozen in it's retracted position (very very rare).

 

Any update on this?
Problem solved? What was it?
Although a long time ago, my experience with Q-Jets is great. As was said previously, you need to know how they work. They're far from "Quadrajunk", just need some respect, that's all ;-).

 

Some respect and someone that knows what they can do and how to make them do it.
Notice in this picture that this guy can afford ANY carb, and what he has on the manifold...

 

Ah, yes, Supervisor. You brought back another fond memory: the "more often present than not" gasket leaks!
Nice pic, btw.