Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

QJ on my SBC build for my 1986 Toyota Landcruiser

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Cliff Ruggles:
All looks good, and yes the area under the solenoid can be filled, that system is not needed.....Cliff

dougbert:
thanks cliff

I got a new caliper and measured my rods. I also was confused as to just how to measure the rods.
I found a page  http://www.carburetion.com/rodshang.asp  which showed a method.

Is this the proper location to measure the primary?

My primary rods measured .044 at this measure point and .036 at the tip.  That would put the rods .029 inches smaller than the main jet of .073

My secondary rod measured .067 inches at the measure point. Looking it up, it shows it is a very lean rod. Moving the DA rod (.044) will enrich it a lot

Cliff Ruggles:
The upper section on the primary rods is in the jets at idle and light load (high vacuum).

The later carburetors could have used quite a few different metering rods.

They will have a secondary stamp, J, K, L, M, P.

The "M" series have .036" tips, the others will have .026" tips.

"K" metering rods are only tapered .005" on the upper section, the "P" rods have a .010" tapered section then "step" to .026" tips.

The J and L rods have a tapered section between steps.

Motorhome carbs use a special primary metering rods that is full taper from around .060" to .036" (nearly as I can remember).

Some early carbs also used tapered metering rod, and an APT system in the baseplate.  "B" series rods are common in early carburetors when APT was used, they have a tapered section between the upper and lower sections...Cliff

dougbert:
Thanks cliff  - lots of info.

I am currently doing the carb because I had foot surgery and am desk bound, so I have done the prior carb.  In addition, I am doing a 2nd carb to develop my QJ skill set. Therefore, below is another carb core I have which I aim to rebuild for the same vehicle above (its the only SBC I have).  I figure doing more than just one carb will re-enforce my knowledge on rebuilding the carbs.

The 2nd carb number is listed as a checker/marine and I don't know if that makes a good vehicle carb or not. If not, I have other cores I can use.

The cores I do have:
17085231 - 1985, M4MED, Federal, Cadillac, manual??: free with engine, has been serviced by cliff, in rebuild stage now Receipe #1
17081283 - 1981, Federal, Checker/Marine, manual tranny: $20
17080504 - 1980, California, Chevy, auto tranny: $49.88
17059508 - 1979, California, Chevy, auto tranny: $23
17058229 - 1978, Federal, Chevy, manual tranny: $27.50
17057213 - 1977, Federal, Chevy, manual tranny: $15 bought Jan 2015 broke air horn in shipment, now parts carb

Below is the 17081283 carb and its attributes:


Attribute--------------------Measured Value--------------------Recipe 1
Idle Tube --------------------------  .030 ---------------------- .036
Idle Channel  (DCR)  ----------------.045 < size < .048 --------.046
Lower idle air bleed -----------------.074 -----------------------.070
Upper idle air bleed (main body)-----.066 < size < .068 --------.067 to .070
Accelerator pump discharge holes --.023 < size < .026 ---------.026 to .028
Main air bleed (main body) ----------.116  ----------------------.070
Main air bleed (air horn) -------------NA-------------------------.070
Idle bypass air ----------------------.108 -----------------------.055
Mixture screw holes -----------------.080 < size < .084 --------.090
Main Jet ----------------------------.072 -----------------------.073
Primary metering rod ---------------.041-.036, .025 tip  (K) ----.044
Fuel inlet seat ---------------------- .125 -----------------------.135
Secondary POE well restriction ------.036 < size < .038 ---------.032 to .038
Secondary POE restriction ----------.052 ------------------------.052 to .055
Secondary tube restriction ----------.025 ----------------------- .036
Secondary hanger -------------------J -------------------------- K or higher letter
Secondary metering rods -----------.056 (CH .057) ------------ .0443

The questions I have concern the attributes in RED above:

is that main air bleed too big?  The type I have is on page 32  lower right picture.

is that IDLE bypass air too big?

will the existing primary rods work  (41K) or should I move to the 44K?

related then, is the existing jet of 72, depending on the rods above, leave alone or go to 73 jets?

thanks

dougbert

dougbert:
Your book is great, it has the info, just hard to find what one needs - lol - needs a Index, mmm sounds like a good project.............

Anyway, found the "large main air bleed" side bar on page 112  which lists the 3 options for the large air bleed. 

dougbert

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