Quadrajet Questions

I didn't see a specific forum for carburetor questions so here goes.  I understand the bernoulli principle so take a look here.

http://www.highperformancepontiac.com/tech/hppp_0311_rochester_quadrajet_carburetor/photo_13.html

What should I see when shining a flashlight down nozzle port?  On my carb I see the emulsion tube.  I don't see a hole in the emulsion tube.  I don't see the top of the emulsion tube.  

Is the emulsion tube one or two piece?

Does the emulsion tube have just two holes; one at each end?

How can I tell if the emulsion tubes are pushed too far in the casting?

If I have to remove the emulsion tube or nozzle how do perform this?  With heat, pull and twist on the tube?

I am doing a carb rebuild and I can't tell if the emulsion tubes and nozzles are set up correct.  I have no idea what the previous owner may have done.

Thanks,
bt  

Beertracker

Is there a problem with the carburetor? It's fine you understand Bernulli's Principle. It will confuse more then help us more.

  If you want to see Brenulli's Theory or Principle in action do this.
1.Get a 500CI Pro-Stock engine at 11,000RPM+.
2.Now with your timing light hooked to the Coil
side of the ignition to replicate a strobe light
effect.
3.Now strattle the engine over the Tunnel and all
the other probes hooked up.
4.Watch the carb stray pattern at each nozzle with
the timing light. Remember the strobe light effect.
Watch the vacuum that is created, that is Bernulli's
Principle.
5.Now have the operator do this each time, so a high
speed camera can be used to see what each nozzle is
doing as it goes the phases of WOT and/or a very slow
WOT.
6.Remeber don't get burnt. Standing over the egine
while your trying to get a good picture of the spray
patterns.
7.A vacuum cleaner motor pulling the air out of a vacuum chamber
now this creates a low pressure area which pulls dirt and small
particles from a carpet. That's Bernulli's Principle.
8.But do you have a problem with the Q-Jet?

There are a few things that go wrong with a Q-JET Caruretor.

1.The throttle Shafts wear out, and create vacuum leaks
2.Accelerator pumps and their bores  wear out.
3.Then guys rebuild them, screw them up so they end
up in a junk box....I have bought boxes of parts from these guys...LOL...

Bob Aka-pepsi1  

What should I see when shining a flashlight down nozzle port?  On my carb I see the emulsion tube.  I don't see a hole in the emulsion tube.  I don't see the top of the emulsion tube.  

A.  which port are you looking down...  in a quadrajet the primary emulsion tubes are in the main body and not visible..

Is the emulsion tube one or two piece?

A.  in a quadrajet. one piece... others may have multiple components. it varies..

Does the emulsion tube have just two holes; one at each end?  

A.   in quadrajets.. they are usually just open at the ends.. others have fine holes drilled in the sides..

How can I tell if the emulsion tubes are pushed too far in the casting?

A.   there is a stop.. they can only go so far in a quadrajet..

If I have to remove the emulsion tube or nozzle how do perform this?  With heat, pull and twist on the tube?   \

A.   they are easily crushed.. wiggle while tugging slightly.. is how i get them out..  i rarely take them out ..

I am doing a carb rebuild and I can't tell if the emulsion tubes and nozzles are set up correct.  I have no idea what the previous owner may have done.

A.   the ONLY WAY to know it to put it on the engine and run it..    once installed.. there are devices called air fuel ration displays/gauges.. and oxygen sensors.. these can cost you between about 60 bucks to 500 bucks... depending on what you want..  most stores sell the least expensive gauges for 35 bucks.. and oxygen sensors start at about 20. and some money for a sensor bung installation in your exhaust pipe...

there are over a dozen quadrajet articles spread out thou the over 40 car and truck magazines on this site..  there are 6 or 7 just here in HPP..

 

Regarding first reply, you must have mis-interpreted my questions.

No, I do not want to see bernoulli principle in action.  Sorry I mentioned bernoulli; never know what words to use here to avoid confusion.  Not my intention to raise any eye brows here.

No, I don't know if the secondary side is working fine or not.  I am trying to figure out if the secondary emulsion and secondary nozzles are installed correctly before I pop it on the engine and crank it up.  I would rather take extra time now while the q-jet is apart and make sure the secondary side is set up right.  I hope this helps.

bt    

Here is the answer to question A. below.  I am looking down into the SECONDARY nozzle port as show in the photo link.  Thanks for the good answer. BT

What should I see when shining a flashlight down the Secondary nozzle port?  On my carb I see the emulsion tube.  I don't see a hole in the emulsion tube.  I don't see the top of the emulsion tube.  

A.  which port are you looking down...  in a quadrajet the primary emulsion tubes are in the main body and not visible..



Is the emulsion tube one or two piece?

A.  in a quadrajet. one piece... others may have multiple components. it varies..

Does the emulsion tube have just two holes; one at each end?  

A.   in quadrajets.. they are usually just open at the ends.. others have fine holes drilled in the sides..

How can I tell if the emulsion tubes are pushed too far in the casting?

A.   there is a stop.. they can only go so far in a quadrajet..

If I have to remove the emulsion tube or nozzle how do perform this?  With heat, pull and twist on the tube?   \

A.   they are easily crushed.. wiggle while tugging slightly.. is how i get them out..  i rarely take them out ..

I am doing a carb rebuild and I can't tell if the emulsion tubes and nozzles are set up correct.  I have no idea what the previous owner may have done.

A.   the ONLY WAY to know it to put it on the engine and run it..    once installed.. there are devices called air fuel ration displays/gauges.. and oxygen sensors.. these can cost you between about 60 bucks to 500 bucks... depending on what you want..  most stores sell the least expensive gauges for 35 bucks.. and oxygen sensors start at about 20. and some money for a sensor bung installation in your exhaust pipe...

there are over a dozen quadrajet articles spread out thou the over 40 car and truck magazines on this site..  there are 6 or 7 just here in HPP..

Read more: http://forums.highperformancepontiac.com/70/9372140/the-general-discussion/quadrajet-questions/#9443205#ixzz2LxOHqZP9  

These links are about the Q-Jet.,. might find what you're looking for.

Click on links.

http://www.highperformancepontiac.com/tech/hppp_0612_rochester_quadrajet_carburetor/index.html

http://www.highperformancepontiac.com/tech/hppp_0702_rochester_quadrajet_carburetor_tuning/modifications.html

http://www.chevyhiperformance.com/techarticles/0606ch_jet_performance_products/index.html

http://www.chevyhiperformance.com/techarticles/49860_rochester_quadrajet_carburetor/index.html

http://www.chevyhiperformance.com/tech/engines_drivetrain/shortblock/0403chp_1974_chevy_camaro_z28_quadrajet_rebuild/index.html

http://www.superchevy.com/technical/engines_drivetrain/induction_poweradders/sucp_0710_qudrajet_carburetor_rebuild/index.html

http://www.carcraft.com/howto/57178/index.html

http://www.hotrod.com/techarticles/engine/edelbrocks_q_jet_carburetor_replacment/index.html

http://www.circletrack.com/techarticles/ctrp_0607_quadrajet_tech/index.html

http://www.circletrack.com/enginetech/ctrp_1008_quadrajet_racing_carburetor_tips/index.html

http://highperformancepontiac.automotive.com/21165/hppp-0612-rochester-quadrajet-carburetor/carburetor-chart.html

http://www.corvettefever.com/howto/53360/index.html

rochester4barrel.pdf

All of these are mostly on quadrajet carbs... not including any electronic versions.,.

 
When The Flag Drops,,,



The Bull Chit Stops,,,


P. Engineer, Engine Builder

Beertracker I sent you 2 PM's

Bob aka-pepsi1  

I did a little more online research and this combined with your info I was able to find answers to my questions.  Thanks to all.

bt