Right away I was reminded that Carter AFB/Edelbrock 1400s don't work very well for wheeling. On the way from Sacramento I went from 350' to over 7600' elevation and maaaan did she get fat up on Donner Summit!
So, having pretty much exhausted my savings account I was looking for a low buck, but sensible solution for these two VERY aggravating issues.
I knew that one can make a Holley 4150/4160 work exceptionally well as an extreme wheeling/crawling carb with modifications. I'd driven my brother Ray's very bada$$ 401 CJ-5 on the Rubicon and knew his 750 Double pumper worked very well even when all I could see up front was blue sky. I asked him to show me what he did to that carb to make it work so well. His solution was simple: He added two pieces of clear vinyl fuel tubing to threaded nipples screwed into the bowl vents and tied together with a tee, then a 2" or so vertical piece of tubing from the tee zip-tied to the air cleaner stud that ended just short of the air cleaner lid.
That's it, nothing fancy, no razoo off-road needle and seats etc. His solution performed the same function as the Holley Truck Avenger, and perhaps even better since both bowl vents had an effective height of 4-5" above the fuel level compared tot he TA's 2" max.
OK, so I had that part figured out. A Truck Avenger carb was running about 425 I recall so that was out. I ended up buying a Holley 4160 600CFM carb with non-adjustable floats from Summitracing for 268.00. I don't need a big carb because my engine develops torque at low-ish RPMs and I just don't like to rev past about 3500 RPM unless something is on fire, Zombies are chasing me or somebody's life is in danger. So yeah, a 600 would suit my needs and then some.
I stress tested the stock Holley in the spring by getting myself burind in deep snow drifts on a fairly steep, off-camber road. I had the old girl bucking and bouncing fairly good and the carb didn't flood, sag or cause any problems compared to my Edelbrock that would have flooded the moment I even looked at that hill.
OK, so the next thing to tackle was the mixture issue. I had previously used the Percy's Adjust-a-Jet kit on my drag car and knew they worked great for quick jetting changes without spilled fuel and torn bowl gaskets...but I wanted something more.
I wanted to be able to adjust the air/fuel mixture from the driver's seat. I am a bit of a Control Freak thus the name of my project
I knew that running too lean or rich for even a short amount of time can wreak havoc on an engine I knew I would need some way of monitoring my Air/Fuel ratio while driving. I thought about adding two Pyrometers, one for each headpipe, but that idea got shelved. I ended up going with an Edelbrock AFR meter from Summit for 100.00 but after seeing just how cheesy it was and that it was narrow-band I bit the bullet and went with the Innovate Motorsports G3 AFR gauge kit.
I installed it with the stock carb and after some very annoying ground issues, got it working. I placed the controller box on the rear slope of the pass side inner fenderwell where it was protected from dirt, mud and water.
Next up was the Adjust-a-jet plate install.
The kit comes with the plate, gaskets, longer bowl screws and a modified accelerator pump arm. I had to purchase the extended fuel transfer tube separately which was annoying, but it makes sense because the kit will fit a variety of Holly 41XX series carbs and not all use the tube.
In the photo above you can see the mixture adjustment screw set for approximately a 64 jet size which is a good baseline for 350' sea level.
I adjusted the mixture while driving, then stopping, getting out, removing the air cleaner and twisting the screw...then repeating. Yes, this was much faster and cleaner than popping a bowl off or having to hang metering rods etc but still took too long and put me in a foul mood.
Once the jetting was set, I adjusted the idle mixtures for best vacuum, RPM and a 14.7:1 ratio.
While I was working on the plate install my mind was pondering how I would control the mixture from the cab just like I did in aircraft.
I had a Holley 3BBL carb off a B-17 radial engine and a Stromberg off of something else in storage so I grabbed them and found their mixture control setups.
Both used a simple needle and port just like the Percy's plate that connected to a spring loaded and dampened lever/bellcrank with a 4:1 ratio with a cable connection at the long end.
Now I had an idea of how I would rig up a control linkage.
About the same time, I remembered that I'd worked on Holleys that had a lever actuated bowl vent!
I ran outside to the Ramcharger and promptly removed the vent lever and retainer plate.
I located the retainer plate on the jet plate and drilled holes for the sheetmetal screws.
I bent up some 1/8th" brass rod for the linkage, removed the threads from the needle with a lathe and soldered a brass washer to the top.
With that working, I went to NAPA and bought a kinda-expensive vernier control cable.
I removed the cigar lighter assembly from the dash and mounted the cable head in it's place. No drilling required!
I fed the cable through the firewall above the pedal bracket and made a loop around the engine compartment until the end was alongside the carb on the passenger side.
I robbed the choke cable bracket off the Edelbrock and welded it to a tab for mounting on the passenger rear carb mounting stud. The control cable was now in place with a nice clear shot forward just above the intake runners. I wanted at least a 4:1 ration for precise control but found I'd made the vertical rod a bit too long. I left it that way because I knew this was just a proof of concept and not even a prototype.
I robbed the choke cable end and soldered it to the end of the vertical rod and connected the cable.
In the photo above you can see where I had to go back and add a 1/4" long piece of .250" solid brass rod to the mixture needle to get the washer loop at the same level as the control rod. I wanted the two to be in the same plane during normal operation and without this, the alignment was all messed up.
I buttoned everything up and began a series of test drives. I immediately learned that there was way too much slack or baklash between my lean and rich adjustments leading to too rich or too lean woes but the concept worked. I topped off in Sacramento and drove to Fresno and back on Highway 99 which is just about flat the whole way. I watched my vacuum gauge and never applied enough throttle to drop to more than 20" manifold vacuum while maintaining 55MPH when at all possible due to traffic. My previous highway runs netted 11-13 MPG with 4:27 gears and 33x12.50 AT tires. measuring a true 32" height. This run just a week later netted 19MPG for the trip! I did my best not to worry the AFR too much but managed to keep it at the 14.7:1 ration for most of the trip.
Life intruded and it was almost 2 years before I could get back to this project. In the meantime I had been playing with a new design for the system that would eliminate the backlash issues and provide better control. What I was after was essentially a full jet size with every full turn of the vernier cable knob. After some calculations and measurements I found the right length of vertical rod and lifting arm to cable movement. It ended up being very close to my original 4:1 ratio.
I went into 3DsMax and laid out a crude new design.
My criteria were that it should be made from off the shelf materials available at Ace Hardware, be workable enough to be built with basic-intermediate tools and be as simple as possible for cost and reliability.
After many months of giving this design 30 minutes at a time I came up with the basic design as shown below.
I thought placing a piece of drilled flat stock between the choke lever assembly and the carb body would be simple and strong enough to support the control rod and not require much effort to build. Well, that worked, but I was getting some resistance from the mixture needle as I raised and lowered it due to the slight amount of threads left over from the lathe job. As the needle moved those thread remnants were hanging up on the viton seals down inside the jet plate and there was enough resistance to cause my mounting plates to twist and raise off the carb bowl...bringing me back to a backlash problem that made accurate mixture adjustments darn near impossible.
Then about the same time I started experiencing MEGA flooding issues that would begin at random....so rich that I couldn't keep the engine running in gear and choking out from the raw fuel and smoke.
My project stopped as quickly as my Jeep did trying to get it backed into the shed.
To be continued...
