Testing quadra-jet secondaries
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 952
Likes: 0
From: Morgantown,WV USA
Testing quadra-jet secondaries
All,
I was wondering if there was a way to tst the stock carb to see if the secondaries were operating. With the car in park I removed the air cleaner lid and held the throttle open to 25oo rpms and then reved it pretty sharply (probably to 4000 or 4500 rpm) and the secondary plates did not open up.
To be quite honest, when driving the car I can not hear if they are opening or not because of the stock induction system and aftermarket exhaust. I realize its vacuum so I will not feel a sudden "kick", but is there a way to verify their operation with the car in park and observing through the operation?
Thank you,
Dan
I was wondering if there was a way to tst the stock carb to see if the secondaries were operating. With the car in park I removed the air cleaner lid and held the throttle open to 25oo rpms and then reved it pretty sharply (probably to 4000 or 4500 rpm) and the secondary plates did not open up.
To be quite honest, when driving the car I can not hear if they are opening or not because of the stock induction system and aftermarket exhaust. I realize its vacuum so I will not feel a sudden "kick", but is there a way to verify their operation with the car in park and observing through the operation?
Thank you,
Dan
Racer
Joined: Jan 2006
Posts: 323
Likes: 4
From: McKinney Texas
With the engine off, and a helper in the drivers seat, make sure the choke plate is open and the secondary lockout lever on the passenger side of the carb is not engaged with the bar going through the end of the secondary shaft. Manually hold the secondary air valves open, and while looking down the barrels, have the helper press the throttle to the floor. The secondaries should open up all the way. If they do not, then the throttle cable needs "adjusting" (quoted, because my '74 does not have an official adjustment mechanism).
If the looks fine in the driveway, but you do not think they are working while driving, wire the secondary lockout lever in position, so the secondaries will not open, and go for a drive. If you do not notice a difference, then your secondaries are not opening, and you have carb adjustment/assembly problem.
Even with a quiet car (like my '74 454 vert) you should be able to distiquish the sound of the secondaries kicking in.
If the looks fine in the driveway, but you do not think they are working while driving, wire the secondary lockout lever in position, so the secondaries will not open, and go for a drive. If you do not notice a difference, then your secondaries are not opening, and you have carb adjustment/assembly problem.
Even with a quiet car (like my '74 454 vert) you should be able to distiquish the sound of the secondaries kicking in.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
I assume you are talking about the '78. Remove the air cleaner and drive the car for a short distance including a WOT blast. You should be able to hear the carburetor make that signature "WAHHHHHHHHH".
If the small primaries are the only thing opening you will not hear that.
cc
If the small primaries are the only thing opening you will not hear that.
cc
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
I assume you are talking about the '78. Remove the air cleaner and drive the car for a short distance including a WOT blast. You should be able to hear the carburetor make that signature "WAHHHHHHHHH".
If the small primaries are the only thing opening you will not hear that.
cc
If the small primaries are the only thing opening you will not hear that.
cc
The last thing they were supposed to do was flip it back before dad drove the car.
Safety Car
Joined: Apr 2000
Posts: 3,802
Likes: 61
From: Wichita KS
Now my uncle who owned an upholstery shop that I worked at had a '67 Caprice 4 dr. with a 396. I went to buy it after he passed away and I let his partner talk me out of it. He said my uncle never took care of it and it smoked etc. I wish I had gone ahead and taken it.
cc
Last edited by CCrane65; Nov 22, 2009 at 08:19 PM.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
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