Vacuum secondary question
Thread Starter
Racer
Joined: Oct 2001
Posts: 317
Likes: 0
From: Gulfport FL
Vacuum secondary question
On the side of the carb there is a metal bar attached to a vacuum thingy, when I start the car, the vacuum pulls this bar all the way in and locks the secondary flaps on the top of the carb shut. Is this vacuum supposed to back off and allow the flaps to move when the engine warms up or what? Because I have never seen this bar in the up position so that it would allow the secondaries to open... How is this vacuum hooked up internally to the carb? is there some sort of temperature sensor that cuts the vacuum to it or is the vacuum cut off when you are at WOT or what? The vacuum thingy is hooked up to a vacuum port right above it and then it looks like the vacuum line keeps going up and makes a shark fin type thing on the top of the carb before going back down into the carb. Or another thought I just had... is the choke assembly somehow involved in cutting off the vacuum?
Any Help would be appreciated... Thx...
Any Help would be appreciated... Thx...
Drifting
Joined: Oct 2001
Posts: 1,699
Likes: 1
From: Westampton NJ
Re: Vacuum secondary question (RoyArms)
Let's see if I can say this right.
The secondary system consists of two "flaps," one is the throttle blades near the bottom of the throat, and the other is the set you describe at the top. The bottom vanes are weighted so they only open with heavy load (as does the top set by vacuum signal). You will not see the secondaries open unless you're driving WOT down the highway with the hood and aircleaner off...they require engine load to be high to open.
Make sense? Well, in any case whenever Lars comes on today, he'll correct what I said wrong. :D
The secondary system consists of two "flaps," one is the throttle blades near the bottom of the throat, and the other is the set you describe at the top. The bottom vanes are weighted so they only open with heavy load (as does the top set by vacuum signal). You will not see the secondaries open unless you're driving WOT down the highway with the hood and aircleaner off...they require engine load to be high to open.
Make sense? Well, in any case whenever Lars comes on today, he'll correct what I said wrong. :D
Thread Starter
Racer
Joined: Oct 2001
Posts: 317
Likes: 0
From: Gulfport FL
Re: Vacuum secondary question (rainman69)
I know they require engine load to actually open them, but they should not be locked with that vacuum thingy all the time should they? they should be free to move with load. When they arent locked with the vacuum, they still require pressure to open them, but when that vacuum is activated they are VERY hard to press open because you are directly overcomming the force that the vacuum applies to the rod. I guess my real question is what are the conditions for vacuum being applied or not to that vacuum lock? and what controls these conditions?
