Secondaries not engaging?

[Alarus]

How can i tell if my secondaries are engaging? other than climb out wile a friend is on the gas to look at it how would i tell? i dont think there engaging...

 

[johnsstang04]

get some tie straps and stop them from opening, then take it for a ride. if there's no difference than they aren't opening. (easy way for passing smog too)

 

[Alarus]

Dont have to pass smog, live in the mountins (superior) if they arnt opening, how would i fix that?

 

[johnsstang04]

you obviously have vacuum secondaries, so there should be a diaphragm with a spring that regulates when the secondaries open. you might want to pull the diaphragm off and see if its seated properly or torn. this should be included with any standard carb rebuilding kit, so you might just want to replace it. the car generally needs a load on the engine before the secondaries will open, so revving your engine and watching the carb is useless.
you're lucky u live in superior.... stupid maricopa county!!!

 

[Alarus]

alright, ill have to check it out when i get it back on the street, i have the steering box removed right now for rebuild, the back seal is shot...

 

[D.Hearne]

If you've got a Holley, remove the secondary diaphram housing, remove the top cover and look to see what spring is there. If it's a black or brown spring and your motor is stock or mildly built, the secondaries will not open until the engine hits around 4500-6000 rpms ( if at all) install a white or purple spring ( you'll need a Holley spring assortment kit to get these) and I guarantee they'll open fully and about a second or two after you nail the throttle. There's usually two different white springs in the pack, chose the one that looks to be the lightest.

 

[Alarus]

not a holly, traded my 2bbl out for a carter 4 bbl, the holly i have is in good shape it was just a nusince to keep getting under the hood to retune it....if i remember right its done with a waight...

 

[D.Hearne]

Why'd you keep retuning it? Once a Holley is set it stays that way. Only thing that happens that would require fiddling with one, is dirty gas, or the ignition getting out of tune.

 

[rbohm]

on the carter, you actually have mechanical secondaries, but it uses an air valve to control the secondary airflow. make sure this air valve is operating freely. once airflow overcomes the weight of the bobweights on the air valve, the plate opens, and you should hear a hissing sound that gets louder as the plate opens.

 

[Max Power]

If I remember right, you have mostly a stock 302. Quite often people new to this hobby, especially those with milder engines, expect a lot more than they get when installing a 4 barrel carb. I have heard a hundred times over the years when people first put on a vacuum secondary carb (or smooth mechanical one) they they don't think the secondaries are opening. 99.9% of the time they are.

Alarus, why do you think they are not opening? Are you comparing this with previous performance on the same car or woth your expectations?

 

[Alarus]

performance between the 2bbl and 4bbl and the intakes, it accually droped a little, that and its a used carb (out of a yard) i did rebuild it however, im looking at getting a new edelbrock 4bbl but thats quite a wile away