70 L-46 quadrajet secondaries?

[Mike F.]

With a properly adjusted throttle cable; how far should the secondaries open with the gas pedal pushed to the floor? (I'm not talking about the air valve which is closed in this picture.)
Should the secondaries open 90* degrees/vertical or somewhat less?

The reason I ask is that my throttle cable needs to be positioned further back off of the metal ridge to get the secondaries to open 90*. Eventually the cable will slip forward until it hits the ridge after x amount of driving.

TIA,
MIke

[Dennis D.]

Re: 70 L-46 quadrajet secondaries?

somewhat less

[Michael W.]

Re: 70 L-46 quadrajet secondaries?

Somewhat less and I've adjusted the cable similar to what you've done.

[Duke W.]

Re: 70 L-46 quadrajet secondaries?

Your CSM should have the procedure/specs for setting up the throttle cable and link to the secondary butterflies.

Duke

[Robert N.]

Re: 70 L-46 quadrajet secondaries?

Highly recommend you read the Lars Grimsrud carburetor papers found at:

http://www.corvette-restoration.com/resources/how_to_articles.htm

From his "Q-Jet Troubleshooting" paper:


Secondary throttles adjusted to open over-center
Results in: Bog or hesitation going into the secondaries, poor WOT performance.
More common that secondaries that do not open fully are secondaries that open too far. Q-Jet secondary throttle plates should NOT open to the full vertical position or beyond. The secondary throttle plates should open to a position where the angle of the throttle plates points and aligns towards the lower edge of the secondary airflow baffle located in the secondary venturi bore. When the secondary throttle plates are opened beyond this point, turbulence in the secondary side actually decreases airflow. Also, if the secondary throttle plates are adjusted to open over-center, they will, as a result, also open too soon. This will cause a stumble or hesitation going into the secondaries. Adjust and align the opening by bending the primary throttle contact tang.