| quadrajet 1978 -1979 [message #355678] |
Sun, 14 June 2020 16:17  |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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I have a 1978 engine and carb in my 76 Birchaven. The carb has a rebuilt sticker on it.
My secondary air valve only opens about 1/3 (hard stop) of the way.All the adjustments are close, but does any one know how far the air
valve is supposed to open?
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: quadrajet 1978 -1979 [message #355679 is a reply to message #355678] |
Sun, 14 June 2020 16:26  |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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All the way, conditions permitting. Reving it in neutral will not meet those load conditions. The vacuum dashpot, wind up spring and downward air flow are a balancing act.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: quadrajet 1978 -1979 [message #355681 is a reply to message #355679] |
Sun, 14 June 2020 17:02 |
Wayne
Messages: 106
Registered: August 2004
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Thanks John,
That,s what I thought. The vacuum rod hits the end of the slot on the air valve lever @ about 1/3 of the way open.
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: quadrajet 1978 -1979 [message #355683 is a reply to message #355681] |
Sun, 14 June 2020 17:33 |
6cuda6
Messages: 975
Registered: June 2019
Karma: -6
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Is that when driving and going to WOT? Or just trying to open it with your finger or at idle?
BTW there are a couple really good QJet videos on you tube about proper tuning and setup.....i forget what the guys name is, he swears alot but he know his stuff and talks about all the things people do to the secondary air flaps thinking it makes the QJ work better when it doesn't.
Wayne wrote on Sun, 14 June 2020 18:02Thanks John,
That,s what I thought. The vacuum rod hits the end of the slot on the air valve lever @ about 1/3 of the way open.
Rich Mondor,
Brockville, ON
77 Hughes 2600
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| Re: quadrajet 1978 -1979 [message #355684 is a reply to message #355678] |
Sun, 14 June 2020 18:25 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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If OFF it won’t fully open by hand with choke open, something is wrong. I’ve seen them where all the parts were there but assembled incorrectly. We might need a picture.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: quadrajet 1978 -1979 [message #355691 is a reply to message #355678] |
Sun, 14 June 2020 21:05 |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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The rod from air valve and the pull off diaphragm was backwards . installed it correctly and now they open all the way.
Does the secondary lock out have a lever to move it out of lockout when the choke is open or does it depend on gravity to unlock it
when the choke opens?
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: quadrajet 1978 -1979 [message #355697 is a reply to message #355678] |
Sun, 14 June 2020 23:09 |
Wayne
Messages: 106
Registered: August 2004
Karma: 0
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Senior Member |
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The rod from air valve and the pull off diaphragm was backwards . installed it correctly and now they open all the way.
Does the secondary lock out have a lever to move it out of lockout when the choke is open or does it depend on gravity to unlock it
when the choke opens?
Wayne Lawrence
76 Birchaven
Bellflower CA
w.lawrence@verizon.net
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| Re: quadrajet 1978 -1979 [message #355699 is a reply to message #355678] |
Mon, 15 June 2020 07:12 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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You should be able to play with choke by hand and see how it opens the lock tang. Basically gravity closes the lock and the mechanism moves it open. So I guessed right on that secondary air valve linkage. I had bought a $750 winter beater a 77 Monte Carlo with 350/4 in Vegas and drove it back. It had same misassembled issue. Easy fix no cost.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: quadrajet 1978 -1979 [message #355700 is a reply to message #355678] |
Mon, 15 June 2020 07:18 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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Also in addition to what Larry said, you can get more throttle pull by slightly sliding rearward and slightly bending rearward the throttle cable bracket at left rear of carb. Engine OFF Hold the air valve open and operate pedal with your left foot as you shine a light down secondaries. The lower throttle plates should go vertical.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: quadrajet 1978 -1979 [message #355701 is a reply to message #355678] |
Mon, 15 June 2020 07:25 |
jhbridges
Messages: 8412
Registered: May 2011
Location: Braselton ga
Karma: -74
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Someone - Lenzi maybe? - removes the secondary lockout on his rebuilds. He says it iosn't really necessary in this service and as you're seeing can create troubles.
--johnny
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
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