Harmonic Balancer Removal

[40]

"i know that you guys know what you are doing.."  

I don't know about that! You are correct......It's a 67 Coupe D'Ville. I could not find any AC-44 spark plugs anywhere in town......I was assured that the AC-R45's are nearly exactly the same other than being one heat range higher and resistor plugs.....Is this correct?? We'll get that carb rebuilt and adjusted properly and see if that smooths things out. I'll let you know!!

[wayne petty]

please... if you are going to tear the carb down...

assemble a spray bottle with some soapy water...

with LIMITed amount of airflow and pressure..   please blow into the top of the main wells both primary and secondary...

while you squirt soapy water at the plugs in the bottom of the main body..

to verify they are NOT leaking..   a serious problem on these ..

http://www.highperformancepontiac.com/tech/hppp_0311_rochester_quadrajet_carburetor/photo_25.html

this article above has some great resources for quadrajet owners and builders...   page though all the different photos.. you will see what i am talking about..

and from a different site...

http://www.underhoodservice.com/article/39766/diagnostic_dilemmas_servicing_quadrajet_carburetors.aspx



i missed one...  that might have some really good stuff...

http://www.florida4x4.com/tech/quadrajet/



oh... and this is a great file... 36 pages...

shows some info on main well plugs.. but also has the chart for secondary air door windup turns..   something NOT listed any where else that i have seen...

http://www.newagemetal.com/pages/Misc/71-77Bulletins/71-77Bulletins.pdf

[40]

UPDATE:
I rebuilt the Q-Jet and followed all of the suggestions in the above articles....good read by the way,Thanks.....and it ran really ragged.Messed with the float setting,air/fuel mix etc but could not get it right.After going completely thru it a second time with the same result....it now has a new 600 Edelbrock in place of the old Q-Jet.Even with the new carb it isn't quite right.It starts fine,idles good but it has a hesitation just after idle and has kind of a cavitation or lope when the speed is leveled off.No vacuum leaks,the timing is dead on and the vacuum advance is advancing the timing as it should.I did not mess with the carb adjustments as it starts  and idles so well.Any ideas???Thanks!

[wayne petty]

UPDATE:
..it now has a new 600 Edelbrock in place of the old Q-Jet.Even with the new carb it isn't quite right.It starts fine,idles good but it has a hesitation just after idle and has kind of a cavitation or lope when the speed is leveled off.No vacuum leaks,the timing is dead on and the vacuum advance is advancing the timing as it should.I did not mess with the carb adjustments as it starts  and idles so well.Any ideas???Thanks!

do you have a vacuum gauge... so you could hook up to intake manifold vacuum... you might want to pick up a set of primary piston springs..



SET-UP SPRING ASSORTMENT
Includes 3" Hg (blue), 4" Hg (yellow), 5" Hg (orange), 7" Hg (pink) and 8" Hg (plain) springs..  edelbrock #1464

http://www.edelbrock.com/automotive_new/mc/carbs_acc/images/1464.jpg

i am taking that you bought a model 1400 street legal edition..

EDELBROCK PERFORMER SERIES 600 CFM, STREET LEGAL ELECTRIC CHOKE CARBURETORS
CALIBRATED FOR FUEL ECONOMY
50-state street legal for all 1980 and earlier General Motors V8s (E.O. #D-215-10). Calibrated for maximum fuel economy. Includes timed vacuum ports, EGR and fuel vapor outlet. Not for computer-controlled engines. Comes with the following jets, rods and springs: Metering Jets - Primary .098, Secondary .095; Metering Rods - .073 x .047; Step-Up Spring - orange (5" Hg).

step up springs are easy to change.. minutes..

post your idle manifold vacuum readings..

and you cruise vacuum readings when the engine is surging..

just an idea.. there are a LOT more people better at tuning these here than i will ever be..

this carb is probably calibrated for a 350 motor.. so it might be a lean surge...

the flat spot might need a larger pump discharge nozzle..  if the flat spot is only temporary..  



but at low speeds slightly off idle..  if you have a lean flat spot. you might think about possibly enlarging the idle feed restriction behind the idle air bleed in the side of the booster venturi.. this is not something you want to do first..
blow it out via the removed idle mixture screws first.. dust and debris can collect..   this is why some AFBs and edelbrocks have terrible problems..



the idle feed restriction/idle jet is where the drill is hanging. the idle air bleed is removed and laying on the table..

let me explain this..  the idle mixture is calibrated with the idle mixture screw.. the idle transition is calibrated/limited by the idle feed restriction/idle jet.



this drawing is of a different model carb.. the but theory is the same..


there was... i cannot find it now.. a tuning manual..   on various edelbrock carbs.. which way to go .. the installation manual was a dozen pages..  the tuning manual was 32 pages.. if i recall..


here is the original version before edelbrock... another great read..

http://www.mymopar.com/downloads/carterafbtuning.pdf

[enjenjo]

The lope at cruising speed sounds like a lean surge. You can change the metering rods to ones 5 percent richer without getting into the carb. The instructions are in the owners manual. Or, you can find it here  http://www.edelbrock.com/automotive_new/misc/tech_center/install/1000.shtml