QJ on my SBC build for my 1986 Toyota Landcruiser

[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.

[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

[dougbert]

well I screwed my base plate on carb #1

following the numbers on page 94, in my rote process, I drilled out my mixture holes to .090 up from .055

Instead of just bumping the size by .015, I went to an absolute size increase to .090

I guess I just paid some tuition on my skills and blew the baseplate

[429bbf]

.090 is just fine just make sure you don't have coil bind on your spring. you may have to clip a couple of coils off so your idle screws will seat. also isn't that a single mab carb?

[dougbert]

had to cut more than a couple of coils, 1/2 the spring. It is a metric screw, the small one.  The tapered section doesn't even touch now.  the springs don't bind, but it bottoms out. 

MAB = Main Air Bleed, ah.  Yeah, has MAB in the horn, projecting out in each venturi

I just spaced it and it was late at night. I checked and double checked, but the "example" was right in front of me and I just followed its .090 value.  Afterward,  I then re-read and saw the .020 increase in the example.  That is the ONLY place in the book where it says how much to increase. Its not even in recipe 1 table.

Ah experience, sometimes hard to get.

thanks