Holley vacuum secondaries - Team Camaro Tech
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post #1 of 5 (permalink) Old May 11th, 04, 12:16 PM Thread Starter
Join Date: Jun 2001
Posts: 259

I suspect that my Holley 800 cfm factory carb has inop vacuum secondaries. What is a good procedure to follow to verify and fix the problem?
Thanks for your help
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post #2 of 5 (permalink) Old May 11th, 04, 01:33 PM
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Location: LR AR
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Block them shut and see if the car runs different at WOT. Worth a shot.

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post #3 of 5 (permalink) Old May 11th, 04, 03:36 PM
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Location: Houston, TX USA
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Another idea-take a twist tie off of a loaf of bread and wrap it around the stem that actuates the secondaries where it comes out of the vacuum housing pot. Put it right up against the underside of the vacuum pot as I believe the stem goes up into the housing when it actuates the secondaries.

Wrap it tight enough that it won't move or fall due to it's own weight or vibration. Then go out and run the car hard and long. Try and get the engine to the point where you think the secondaries should be open. After that, raise the hood and look to see if the twist tie has been pushed down on the stem. If so, you now know that the secondaries are working.

1969 383CI, T-56, 12 bolt-3.31 posi, 13" C5 Rotors, PBR Calipers, rear disc system..
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post #4 of 5 (permalink) Old May 11th, 04, 04:52 PM
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Location: Austin, TX, USA
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After trying one of the other tests, if you suspect they are not working, remove the clip from the actuator rod and servo from the body. Make sure the little red paper washer is installed between the servo and body. While the servo is off, you can apply a vacuum to the port to be sure it will hold a vacuum.

68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
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post #5 of 5 (permalink) Old May 12th, 04, 09:25 AM Thread Starter
Join Date: Jun 2001
Posts: 259

Thanks for the great ideas!!!
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