Quadrajet
Thread Starter
Intermediate
Joined: Jan 2010
Posts: 26
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From: Balto Md
Quadrajet
OK, I have rebuilt my carb again and still runs rich. It is a 76 vette carb # 17056206. It has 76 jets in it and I'm thinking its to much. And now it looks like the power piston is stuck. I know I need to take it apart and replace the plastic retainer but does anyone know the right jet size before I take it back apart? And if I change the jets to smaller ones should I change the 44 26 tip metering rods?
Race Director
Joined: May 2006
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77 is the correct number download this document and scroll down
http://www.corvettefaq.com/c3/QJetTuningPaper.doc
http://www.corvettefaq.com/c3/QJetTuningPaper.doc
Tech Contributor
Joined: Aug 1999
Posts: 14,379
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From: At my Bar drinking and wrenching in Lafayette Colorado
If you're running rich, you have problems not related to the jets. You need the 77 jets in that carb for it to run right. The rods should be 48's (48K). There is no need to replace the plastic power piston retainer - it has no effect on performance or operation, unless it is broken in a way which jams the power piston.
Lars
Lars
Last edited by lars; Oct 23, 2013 at 01:13 PM.
Burning Brakes
Joined: Jun 2013
Posts: 1,076
Likes: 148
From: Hunterdon Cty NJ
Lars, I gave the paper a quick read and that is some great stuff! I have been thinking that I would really like to know about tuning Q-jets and tihis will be the ticket, thanks for taking the time to put this together.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
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From: At my Bar drinking and wrenching in Lafayette Colorado
I don't show that I have sent you a paper... Don't use any of my papers you find posted on the Internet, including the ones posted here on this Forum: Those papers are outdated and obsolete - don't use them. For current, valid papers, e-mail me directly a request for the papers you want.
Lars
V8fastCars@msn.com
Lars
V8fastCars@msn.com
Thread Starter
Intermediate
Joined: Jan 2010
Posts: 26
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From: Balto Md
Thanks I appreciate the help. Found a carb shop close by and they said the same thing. The 77 jets and 48k rods are right. But I have 76 jets in carb. Took the air horn back off and one of the metering rod arms was bent down. Bent it back in place and polished the power valve assembly to a mirror finish, recommended by shop to prevent sticking. Put everything back together and when for test ride. What a deference. I also tapped the air horn so I can adjust the auxiliary for power valve. Can't final tune car yet until MSD distributor comes in hopefully tomorrow. Old one just plain worn out. Thanks again. 
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
Yes. When the factory stuff is set up correctly, these cars will run and drive well. You don't have to drop a dumptruck load of cash into them .
You can spend a bunch of money on trick parts, and make the car DIFFERENT. But it's not so easy to make the car BETTER.
You can spend a bunch of money on trick parts, and make the car DIFFERENT. But it's not so easy to make the car BETTER.
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Tech Contributor
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From: At my Bar drinking and wrenching in Lafayette Colorado
Lars
Thread Starter
Intermediate
Joined: Jan 2010
Posts: 26
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From: Balto Md
I did run the APT deeper. I'm at 2 turns from bottom now. Put in MSD distributer tonight and hope to start it up and finish tuning tomorrow. I'm keeping my fingers crossed. I was getting to much advance at idle before.
Burning Brakes
Joined: Jun 2013
Posts: 1,076
Likes: 148
From: Hunterdon Cty NJ
Hey Lars, I was looking at the link that Melwff posted, if that is not correct info I will email you for the correct info. I see you also have timing info. I want my 70 454 to run correctly. Thanks
Le Mans Master
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From: Oxford MA-----You just lost the game!!!!
Scott
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From: At my Bar drinking and wrenching in Lafayette Colorado
Lars
V8FastCars@msn.com