Quadrajet Problem Solving > Dialing in your rebuilt Quadrajet carburetor

QJ on my SBC build for my 1986 Toyota Landcruiser

(1/3) > >>

dougbert:
I have been building my SBC 350 for sometime and finally got it started. I am currently using some QJ I bought off of ebay for now, but have been building the QJ that came with the old SBC.  I built it for torque on off-roading.

Vehicle:
1986 FJ60,  4.11 diff gears,  33x15 tires (sometimes will have 35x17s).  Toyota 4 speed, with Ranger overdrive gear splitter (27%).

Engine:
1973 4 bolt mains,  350 bored .060 over, so 360ci now
GMPP Vortec cast iron heads (http://www.strokerengine.com/VortecHeads.html)  180cc runners, 66cc chamber
compression 10:1

cam: retro roller lifters + roller rockers
lift: .458/.458
duration: 206/210 @ .050
LSA: 111
ICL: 107
RPM Range: 1000-5000

Rockers:  1.52

Now for the QJ:

Quadrajet  #17085231  1825  HMB
Has already been in to Cliff for base brass bushings, and plating.
Have kit as well.

Measured the following:

Attribute-----------Measured Value----------------------Recipe 1
Idle Tube                   .036                                           .036
Idle Channel              .055 < size < .059                       .046
Lower idle air bleed    .070                                           .070
Upper idle air bleed (main body)    .067 < size < .070     .067 to .070
Accelerator pump discharge holes   .073                        .026 to .028
Main air bleed (air horn)                .082 < size < .088     .070
Idle bypass air                .055
Mixture screw holes         .055                                      .090
Main Jet                          .067 < size < .070                 .073 (kit)
Fuel inlet seat                  .128 < size=.130 < .136        .125 to .130
Secondary POE well restriction     .039                          .032 to .038
Secondary POE restriction            .052                         .052 to .055
Secondary tube restriction           .025                          .036
Secondary hanger                      N                               K or higher
Secondary metering rods                                            .045-.055  (DA kit)


My caliper broke and am waiting for new one to show up, so I don't have measurements for the rods at this time

Now the issues I see are the ones in RED where they are larger than expected. I just did read a post by Cliff indicating a part he sells, that is a drive in or a screw in for Idle Channel

The Accel pump discharge holes are way big, but I have check them several times.  The lower picture on page 34 of the book, is there I measured the holes exactly where the red straws are pointing. They look and are larger - .073

And the main air bleed (air horn) is pictured on page 32, the right top pic with the pin vise inserted into the hole.

Comments, suggestions on what to proceed are welcome

dougbert



My aim is to get to Recipe 1, as noted in the right most column.

dougbert:
Also the secondary tube restriction at .025 seems small.

Cliff Ruggles:
The accl pump discharge holes are much smaller and deeper in the casting, you are only measuring the outer holes at the outer partition.

I'd leave the DCR's alone for the moment, they may be OK if you don't go too big with the idle tubes.

You should be using a .135" seat for that power level and that's what would be in a kit if we supplied it.

I'd leave the bleed tubes stock at .025", at least for initial testing.  If you are using DA rods .036" is fine....Cliff

dougbert:
Thanks for the insight

The Accl pump discharge holes come in at .026 with .028 being too big for the hole - those drills are as small as my diabetic needles, ouch!

Attached is a pic of the discharge with a .026 drill inserted.  The key was the angle of the hole.

dougbert:
(That post modification time window is too short)

1) The Accl pump discharge holes come in at .026 with .028 being too big for the hole - those drills are as small as my diabetic needles, ouch!

2) Ah,  DCR = Down Channel Restrictor.   Okay

3) Yes, I have the .135 seat and it came in the kit

4)  Okay will leave the bleed tubes at .025 for now, and yes the kit has the DA rods.

I think what you concluded with is that I could change the bleed tubes in the future upto .036, after testing.


Summary mods I will make:

1) I will enlarge the mixture hole to .070
2) Install the 73 jet
3) Install the .135 seat
4) Install the K hanger
5) Install the DA rods
6) Install the primary rods that also came in the kit

and leave the rest alone for now.

In addition:
This QJ is a M4MED (made only for two years).
I will also do as you told me a year or so ago, in filling the thermo switch valve cavity (pencil is in that cavity) with lead and basically make the connector inert.

That connector did some fuel throttling based on temperature, and you indicated that I don't need it - probably was emission control just prior to the computer controlled models.

Navigation

[0] Message Index

[#] Next page