General Category > Quadrajet Carb Talk and Tips

Upper Idle Air Bleeds

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jagness:
I'm working on a 17054907 for a 410 CID Olds with 10.3 : 1 compression, and this hydraulic flat tappet cam: 230/236 @ .050, 274/286 adv., .522/.522 lift, 112.0 LSA.

The owner rebuilt the carb sometime back and vacuum was very low at idle. When I took it apart, he had put way too much epoxy on the well plugs. The baseplate and main casting were glued together, but it also filled up the cavity in the baseplate so that the gasket couldn't seal. I've never seen one like that!

I have that problem fixed, but I just discovered that the upper idle air bleeds (in the airhorn) are .070". Way to big! How do I fix that?

Here's all of the idle circuit specs:
Idle tube, 0.038
Idle down channel, 0.059
Lower idle air bleed, 0.070
Upper Idle air bleed, 0.070
Idle bypass air, 0.110

Cliff Ruggles:
Are there brass inserts in the upper idle airbleed locations or just drilled in the casting?...

jagness:
No, it doesn't have brass inserts in the upper idle air bleeds.

Kenth:
Are you sure you are measuring the idle bleeds in air horn?
There are two sets of air bleeds in the air horn, sizes from factory are .053" idle air bleeds and .070" main circuit air bleeds next to the idle air bleeds.

If the idle air bleeds are enlarged to .070 you may take them up to .120" for .046" brass inserts.

jagness:
I tried to post a pic but it didn't work. I'm assuming that the bleeds closer to the front of the carb are the idle bleeds. The ones to the outside of the screw hole are the main bleeds. Those do have a brass insert and are .046".

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