Quadra Jet secondaries don't work?

[mainelaker]

I just purchased my first Vette, it's a 1979 L82/four speed. I was going through the car today & after roadtesting I don't think the secondaries are opening. I haven't worked on a quadra jet in about 12 years but I don't think the secondaries will open while you rev the engine on a lift. So how do you check them quick & easy to confirm that they open properly? While driving the car it didn't seem to have the punch my old 1979 Z28 had when I still ran a quadra. In fact this car won't even break the tires free leading me to believe only the primaries are working. If it matters the car runs perfect otherwise & there is a new vacuum break installed by the previous owner.

 

[TOMMAY]

It's been a while since I worked on mine too,but you're right it's hard to get the secondaries to open just revving the engine without a load.But one thing fore sure,you can definatly hear and feel when the secondaries open,if you don't hear when they open they're not opening.

With engine off depress petal to floor and check to see that the butterflies on the secondary side are almost fully open,make sure your tv cable or kickdown cable is not restricting the throttle from fully opening.There's a little pin on the pass side of carb that fits into a notch to keep the the secondaries from opening when the choke is engaged,sometimes it stays engaged even when the engine is at full operating temp.

If all this seems ok,the secondary air door can be adjusted to open with less airflow,takes an allen wrench and a screwdriver and a mirror to see where the allen wrench goes to adjust the tension,go to a qjet web site to see a picture and direction to adjust.Just remember a little goes a long way.

Good Luck

Tom

 

[mainelaker]

I thought the secondaries will not open without vacuum applied, i.e. engine running?

 

[brusso]

Try this site for secondary operation/adjustment.

http://duzy.8m.com/monte/ccquadrajet.htm

 

[drags1998]

The secondarys (sp) on all quadrajets are mech. NOT vacume.The air dams are vacume. Check the vac. break to make sure it pulls the choke link completely off the forementioned pin.If memory serves me correctly the air dam ajustment should be 3/4-7/8 of a turn from just starting to close the valve!!!

 

[Greekman]

Mainelaker....mine was doing the same last year. On a road test I would floor it at about 20mph..and the secondaries should open up and if they do you WILL hear them! It's a deep "throaty" sound and you will feel the additional power.

My car when shifting on a hard acceleration was "falling on its face" between gears and I new that wasn't right. Took it to our Chapter Service Tech Advisor and his shop rebuilt the carb.

That did the trick. No complaints and I have to keep my foot out of it on hard acceleration between gears or I'm into the Red Line pretty fast and close to "floating" the lifters!


Good luck.


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