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-   -   any thoughts on my q-jet idling issues?? (https://forums.maxperformanceinc.com/forums/showthread.php?t=638370)

67cruiser 07-09-2010 01:40 PM

any thoughts on my q-jet idling issues??
 
IVE STUDIED CLIFF,S BOOK FOR HRS. & i still have a small idling issue id love to correct, In park my car idles about 950 rpm,s and when i drop it into gear it dyes on me. I don,t have a power valve and currantly running 65 jets, small float and a .140 fuel inlet needle seat combo.Idle tubes are at .037 Idle down channel,s set at .052, carb. comes on super strong, i just having fits with idling, any thoughts??? Going to check my float level again today, i had it set at 1/4.Timing set at 14, Both idle screws are all the way out, looking for a little help!!

bnorris_74 07-09-2010 02:06 PM

Are you using vacuum advance to the distributor? Full manifold or ported vacuum?
Is your vac advance (if you're using it) set to limit the amount of advance?

I don't believe your problem is associated with the float.
If you screw the idle mixture screw(s) in all the way, will the engine stall out?

With your screws all the way out now, sounds like you still have a restriction somewhere.

67cruiser 07-09-2010 02:09 PM

Just checked my float, At heel of float or about 3/16 its set right on 1/4, air bleed in the horn is at .070 idle down restri. set at.045 running ported vacum off base of carb.

462-6spd 07-09-2010 02:18 PM

Is it rich at idle? Does your carb have APT? If so, you might want to turn it in a little more to lean it out a bit, also check to see if the spring under the piston is too stiff to allow the piston to retract. Also, may want to lower your float a bit? I just rebuilt my Q-jet on my '79 TA and it was way rich at idle, I had my float set at 1/4" and it was too high for my carb.

Also, Cliff has a web site, and he has a forum that has a lot of good info, he seems to be on there quite a bit based on how many replies I see from him. Here is a link to his site. http://www.cliffshighperformance.com/

Murf'sDad 07-09-2010 02:24 PM

What have you got for idle air bypass? If your idle screws aren't having and effect I believe you need little bigger idle tube. This is off the top of my head without going back to Cliff's book to check.

Stewart

BVR421 07-09-2010 02:27 PM

take care of ignition problem first

67cruiser 07-09-2010 02:33 PM

No ignition ploblems at all, car seems to start right up, my apologies i believe i stated channel restriction was .045 i meant .054, typing skills suck!! Not running a power piston or metering rods.
No choke either.

Kenth 07-09-2010 04:07 PM

What engine size and camshaft used?

What carb-#?

Idle circuit upper and lower airbleeds sizes?

Vacuum present in "ported" tube at idle speed?

Idle mixture discharge ports sizes?

67cruiser 07-11-2010 11:03 AM

406 cubic inches, carb. 17046240, lower air bleeds .070 crower hrdraulic cam, sorry looking for my card?? As for idle ports .098 on both holes.

67cruiser 07-11-2010 01:59 PM

typed to fast 17056240 carb. my apologies

67cruiser 07-11-2010 02:36 PM

No. of the cam is 60916 Crower 278 H

Kenth 07-11-2010 04:48 PM

I would use at least .039" idle tubes, .059" idle channels, .110 bypass air and .100" mixture needle discharge ports.
After testing you may want increase the tubes to .040" and idle channels to .064?

Formulas 07-11-2010 07:52 PM

No power piston... did you plug the vacum feed to the power piston ?
If not then theres a vacum leak there.
If you didnt plug then just drop the piston back in there.


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