primary and secondary break
#1
primary and secondary break
I recently installed a non cc carb on my 83 ta. It only has the secondary vacuum break. I have heard that it is not necessary but by name and pictures a primary break is usually on the carb. Is the primary vacuum break necessary? Car seems to run correctly accept for one issue I am having. Whenever I floor the gas pedal,high idle cam kicks in.
Last edited by Rich1374670x; 12-17-2018 at 11:00 AM.
#2
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: primary and secondary break
the forward vacuum break on third gens provides two functions. it cracks open the carb slightly once it is started with the choke on (the motor starts and vacuum is applied to the diaphragm). it also works in conjunction with the secondary air valve spring to delay opening of the secondary air valve. under high throttle vacuum decreases and the break's plunger comes out releasing the air valve linkage.
not sure which rear break you have. some provided a 'dashpot' function to delay, or slow, the closing of the throttles.
not sure which rear break you have. some provided a 'dashpot' function to delay, or slow, the closing of the throttles.
#3
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Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: primary and secondary break
If the choke comes back on when the vacuum goes low, then its electrical function isn't working right. It should be completely opened by the thermostat and then never come back on once the engine has been running for more than a few minutes. It should take quite a while after the car is stopped to cool back down enough to close the choke again.
#4
Re: primary and secondary break
If the choke comes back on when the vacuum goes low, then its electrical function isn't working right. It should be completely opened by the thermostat and then never come back on once the engine has been running for more than a few minutes. It should take quite a while after the car is stopped to cool back down enough to close the choke again.
#5
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Car: 1987 SC/1985 TA
Engine: 350/vortec/fitech
Transmission: T56
Axle/Gears: 3.27 9-bolt
Re: primary and secondary break
no
power from the choke comes from the alternator. when the alternator is not spinning the choke doesn't get power
power from the choke comes from the alternator. when the alternator is not spinning the choke doesn't get power
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