School me

[69 Rustang]

The filter is such a small obstruction to the airflow

I have actually seen dyno test results where the filter improves airflow. Apparently the theory is that the air filter tends to straighten the airflow out and cars will make more power with the filter in place than without it.

 

[Max Power]

Sorry dude. It just helps. There are two things I don't know: Tranny's and carbs, so this is a big time learning experience.

All I know is my Edelbrock carb sits under my airfilter and a small screw turned clockwise or counter clockwise effects my engines RPM's at idle

Cool, I'll give it a shot. I have to set up for some pics for an ignition article anyway, so I will set up a carb and take some shots. It works for Holleys, I have no clue about Edelbrocks.

I have to see if I have a paper clip around here...LOL!

 

[Max Power]

OK, here is your garden variety Holley Model 1850, 600cfm carb:
View attachment 450642

Here is the rod that connects the vacuum secondary diaphragm to the secondary throttle plates. Install the paper clip at the top of the rod as shown here. This paper clip is a little to big, but you get the idea.

View attachment 450644



When the secondaries open, the diaphragm goes up into the diaphragm housing, up like I am pushing them here. The primaries need to be open for this to happen, so if you are trying it on a bench like I am here, crack the primaries before pushing the rod up,

View attachment 450646

The rod going up into the diaphragm forces the paper clip down the rod. When you close the throttle and the secondaries return to the closed position, the paper clip will stay where it slid to. If your secondaries are opening, your paper clip should be at the bottom of the rod, as shown here.

View attachment 450648

 

[Cobain03]

done the paperclip trick. my paperclip does NOT move. we measured vaccum in park and drive.
park: 800 rpms and 16lbs
drive:500 rpms and 10 lbs

 

[Max Power]

Did you go out and drive the car with the paper clip on?

Did you do some wide open throttle blasts?

 

[Cobain03]

did one and the clip did not move. took the secondary diaphram apart and it had the yellow spring in it. so io switched to the white spring. 2nd time around it moved and all runs was at WOT.

 

[DJCarbine]

did one and the clip did not move. took the secondary diaphram apart and it had the yellow spring in it. so io switched to the white spring. 2nd time around it moved and all runs was at WOT.

There is a white spring?

 

[Max Power]

So you're all set then?

 

[19stang66]

Thanks for the pictures and description Max Power! Those helped me out a lot. I'm with geostang on not knowing a whole lot about carbs, so anything you guys post helps.

 

[Max Power]

No prob, 19stang66.