General Category > Quadrajet Carb Talk and Tips
Setup Questions
omaha:
Ok, as far as the DCR's go, yes they can be removed and replaced. Little heat and tiny screw yada yada. Bypass can be resized at it's exit point by using a steel ball and peening it into the hole in baseplate, makesure to use a ball large enough so it don't get stuck in the hole, the idea is to peen the hole smaller, not jam a steel ball into it. so if bypass at .110 use a .150 ball at least maybe .175 even better. Alternative method would be to drill tap plug redrill etc.
The thing im lookin at here is where is that fuel coming from?? If the primary blades are closed AND the needles are seated the only ting left is the transition slot and it should only be showing about ~.020-.030 and with no extra fuel from the needles (which is normally there) the only thing I can think of is that the primary/idle well plugs are leaking OR the needles are the wrong type (don't know if that's possible, jus grabbing at ideas at this point).
Are you sure your secondaries are closing all the way? Kinda hard to blow a 10.2:1 on just the transition slot and bypass air. Got me stumped for sure!!
Chief_Wiggum:
Thanks, omaha. That's what has me confused as well. My carb number is 17059212 and the idle screws look like these:
http://cliffshighperformance.dreamhosters.com/metric-idle-screw_popup.html
but the ones that came out of it look like this:
http://cliffshighperformance.dreamhosters.com/early-idle-screw_popup.html
Is there a way to check to see if they're actually seating all the way? Since the ones Cliff sent screw right in, I would guess they're the correct metric idle screws. But at this point it sure seems like that must be the problem since there shouldn't be a way for it to get idle fuel except by the idle screws correct? Even with the idle down channel restrictions at that size I should be able to kill the engine with the idle screws seated correct?
I double checked the fast idle cam as well, and it's definitely off the fast idle cam when the choke is open.
When I rebuilt the carb I did double check that the primary and secondary throttle blades closed all the way as that is one problem Cliff mentions is common in the book. I also checked the idle well plugs and sealed them with epoxy. They were staked and weren't leaking.
omaha:
Yes I think you are onto something there. The needles should physically fill the holes if you look at the exit of the idle port (into the venturi area, from the bottom). you should actually see the needle's sticking out quite a ways when the needles are bottomed. I guess you could blow some air through from the top of the idle passage while spraying some soapy water at the exit point to see if they are actually closing the port. Of course, air will blow through the transition port too but try to concentrate on the idle ports exit. maybe block the transition port with some thing. You wont need much air, should have very little to no bubbles with the needles seated. makes me wonder about the base plate if it is the original one. different years had different needles and styles of needles. Good luck!
429bbf:
i think omahas on the right track . id install the old idle needles and screw them all the way in . ether someone tapped the holes for the old style needles or you got an old base plate . the metric needles will screw right in an old baseplate and act like there right . but they wont slow down the fuel.
Chief_Wiggum:
Ahhhh..
I'm hoping to work on it some tomorrow. I'll post back on results. Also, I called Cliff and he set me up with replacement down channel restrictions so I'll install those as well. He also indicated I can completely plug the bypass air as he doesn't think I'll need it with this engine at all. So, some work to be done yet.
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