problems with my "new" carb

[megaladon6]

stock q-jet is 750 cfm but the metering rods and air-valve setup (also used in the edelbrocks) allows the use of too large a carb.

can you post a couple of pics of the links and lever?

 

[85 Cutlass Brougham]

The question of CFM is where a lot of people mess up. There are 750, 800, and 600 CFM Quadrajets, depending on application and year. The 800 is Cadillac only from what I have read, but the 600 and 750 were used on everything else. There is no physical difference in the castings or throttle blades between the 750 and 600. The actual difference lies in the air valve stop being longer on the 600 than the 750 and keeping it from opening all the way. There is an easy solution though: Grind down the stop with a die grinder and you have a 750 (Takes 5 min and can be done with the carb on the car and without removing a single part). I have no idea what the difference is between the 750 and 800, maybe the 800 is only a myth like the Loch Ness Monster or Toyota's claimed 65mpg for the Prius...

Oh, and there is a big difference between the Edelbrock Performer (Cough-Carter AFB) and the Quadrajet with respect to the air valve design. The AFB uses a counter weight to keep it closed and is not adjustable. The Quadrajet uses spring tension to keep it's valve closed and the tension is adjustable, so you can vary the actual size of the carb to suit your needs.

Like the AFB ( easier to type than Edelbrock Performer), the Quadrajet uses a power piston and spring setup to actuate it's primary metering rods. Unlike the AFB, the Q-Jet requires removal of the air horn to get to the pistons and springs. Also unlike the AFB, the amount of rise out of the hole that the metering rod can go is fully adjustable, so you can limit how rich it can go on the rod. I honestly forget how the secondaries work on the AFB and am just too lazy to look at the one I have in my tool cabinet right now. It may be the same as the Q-jet with the air valve door actuating it. The only tuning my AFB ever needed was a switch to one step weaker step up springs as it ran slightly rich on tip in.

I will also say that the Q-Jet's tip in response is just incredible-even with the original 79 van jetting it has. It chirps the 1-2 shift at 1/4 throttle because the high velocity through those small primaries creates an abundance of low RPM torque.

 

[Chillin014]

okay i'm back in this thread now.

I have the tv cable hooked up and out of pure ignorance as to how to adjust it i simply made the wire snug. I have like half a foot of extra wire coming out the top of the connector on this new tv cable im using so i just use this little cylinder with a screw in it to stop the line from retracting through the mounting fitting. I dont know how to adjust it though, it doesnt have the typical button on it, it has some other weird piece that is inside the housing and can be pressed through.

When i was driving hte car the first time (with a little slack between that tiny "cylinder" stopper and the fitting) the car seemed to studder this rapid hesitation feeling during downshifts and then continue on into the gear. I came back and readjusted it but havent taken the car out again. It seems to drive normal otherwise.

Also, to clear my fuel line I bought a small edelbrock air filter. this wont cause any kind of restriction will it?

hopefully in this pic you can see my linkage set up

 

[85 Cutlass Brougham]

What transmission do you have? If it is a TH 350 it is not a TV cable. Also, is the cable hitting the manifold runner? If so, that is not a good thing. That bracket is why you are having such a long cable. The factory one is out farther back. The air cleaner may cause a restriction at high RPM, but should be fine 99% of the time. You can't run a traditional 14 in open elemet air cleaner with that carb and a HEI ignition anyways unless you run a 1.5-2 in spacer at minimum. The HEI will hit it and not allow it to seat. Moroso offers an offset base air cleaner that solves this.

 

[Chillin014]

What transmission do you have? If it is a TH 350 it is not a TV cable. Also, is the cable hitting the manifold runner? If so, that is not a good thing. That bracket is why you are having such a long cable. The factory one is out farther back. The air cleaner may cause a restriction at high RPM, but should be fine 99% of the time. You can't run a traditional 14 in open elemet air cleaner with that carb and a HEI ignition anyways unless you run a 1.5-2 in spacer at minimum. The HEI will hit it and not allow it to seat. Moroso offers an offset base air cleaner that solves this.

yeah thats why i got the edelbrock one cause i knew it would fit since it was raised. i'll check into those other air cleaners later...

im not sure what you are asking about the cable hitting the manifold runner. yes i'm running a th350. and the cable you see is NOT the original cable, it came off the TCI th350 that was given to me and i assumed it was the same thing. I only put that cable on there because i think the other one is too short.
what is the cable then? here's a link i found and have been reading.
http://www.tvmadeez.com/article/index.php

 

[megaladon6]

the th350 and 400's have a kickdown/downshift cable, the 200-r4 and 700-4r a TV cable. the TV controls your shift points, hardness, and timing. a kickdown cable just makes the trans downshift when you tromp on the gas.

 

[Chillin014]

the th350 and 400's have a kickdown/downshift cable, the 200-r4 and 700-4r a TV cable. the TV controls your shift points, hardness, and timing. a kickdown cable just makes the trans downshift when you tromp on the gas.

are you sure? cause every website i read says thats the misconception is that its simply a kick down cable, but your probably right cause everytinme i have searched about it it only mentions the 200 and 700. am I probably good just making this wire snug with little slack in it? the kickdown cable i've got on there is a little different than gm's regular style, the housing "button" is this little piece that you actually push through the housing in order to move that little threaded shaft. i might just put the old one in to avoid myself the headache if it will reach.
i dont know what all that stuttering in the hesitation was about when i went for the first test drive. oh well.

 

[megaladon6]

unfortunately i haven't adjusted a kickdown cable so let's go to the repair manual..............pre 1980 .ok theres a "snap lock" that you need to pry up with a screwdriver, then compress the locking tabs ad disconnect from the bracket, set the carb to WOT and push the snap lock onto the cable into the locked position and you're done.
81 or newer: depress the pedal to WOT

 

[Chillin014]

unfortunately i haven't adjusted a kickdown cable so let's go to the repair manual..............pre 1980 .ok theres a "snap lock" that you need to pry up with a screwdriver, then compress the locking tabs ad disconnect from the bracket, set the carb to WOT and push the snap lock onto the cable into the locked position and you're done.
81 or newer: depress the pedal to WOT

hmm okay thanks. i think the cable just needs to not have too much slack in it for the most part. i need to get me a manual.