Rango.....1942 Willys MB

[Metcalf]

Thanks. I think the underdrive will be pretty neat. I am building it so it can be removed if broken and a standard D18 input gear used. I am also going to include an access panel in the tunnel to do just this. The D18 gear shouldn't take up much room in the spare parts bag. That gives me a little more piece of mind on longer trips with some one off parts.

I am leaning toward 4.88's also. Even without an overdrive its only 63mph at 3000rpm with the 35s. This should make for a nice 2500-3000 cruise at 50-60 most of the time. I don't have much reason to go any faster in this thing...

 

[Metcalf]

I jetted it down again.....from 46s to 45s. The seat of the pants feel is even better. It seemed to fix my flat feeling from 3000-4000rpm. I stuck in a new test plug in #6 to watch for a few weeks. I will see what it tells me. I think I am getting pretty close. Being at 7460ft at the house sure makes things different than most other data I could find....

I did find a nice way to orgainize my growing jet collection.

It an aluminum fly fishing box....

I REALLY like that you can change the jets without having to spill any fuel. It only takes about 5 minutes to change a set of jets right now. I need to put a small valve in the fuel feed line. That would make it even easier. I wouldn't mind having a nice see through fuel filter, pressure gauge, and valve on the carb inlet.

 

[Hill Bill E.]

Did a little more carb tuning tonight...

I would say one lacking area on the autolite 2100 is the ability to adjust the accelerator pump linkage.

....................

I get a slightly hesitation at about 2000-2500 rpm when snapping the throttle under no load. Under a load, as in driving, there is no flat spot at the same speed.

Still tuning.....

Going through the same thing on my CJ right now, (258CI with a 2100 swapped on)

My Power Valve died, which led to a complete rebuild of the carb.

I also had a dead spot, and now it's gone! I realized during this rebuild that I missed 2 ports during the initial rebuild, and they were plugged solid.

I used a small drill bit (#56 I think) to clean them, after a torch tip cleaner failed to the job.

These are the 2 ports I missed 6 years ago, when I did the swap:

After the cleaning, and new power valve, my CJ is running sweet again!

Still have some tweaking to do. Running #46 jets right now, where my research has showed that 47's work best for my swap.

Love the build!

HB

 

[Metcalf]

cool!

Those are the discharge ports for the accelerator pump circuit I believe.

#47 jets would probably be pretty close to correct for 0-2000ft on a 4.2 liter motor from what I have read. My little 3.7L engine at 7500ft needs a BUNCH less jet than the stock #47s I have. #45s seem to be really close. I don't know at this point if I will go down to 44s or not. The motor is running pretty dang well right now. What do your plugs look like with the 46s at your elevation?

Remember, jet size is basically for cruise speeds above the opening vacuum of the power valve. Once the power valve starts dumping fuel the jets are not providing all the fuel. I wonder what the orifice size is for the power valve 'jet' area in the carb base. That would be interesting to know. From that I think you could figure out the percentage of fuel vs the main jets that it is adding under full throttle ( or when the power valve is open ).

I like old school tuning, but with our modern fuels its MUCH harder to read plugs. I have been tossing around the idea of getting a wide band O2 meter to really do some proper carb tuning. I would bet that most carbs are run rich most of the time in common practice.

 

[Hill Bill E.]

................
I like old school tuning, but with our modern fuels its MUCH harder to read plugs. I have been tossing around the idea of getting a wide band O2 meter to really do some proper carb tuning. I would bet that most carbs are run rich most of the time in common practice.

I like tuning them.....sometimes :elkgrin:

Grew up working on points/condensors and carbs, way before any type of TBI or EFI was commonplace!
My first rig I ever owned was a '58 Dodge 1/2 ton truck. Between our old trucks and the tractors, I got a lot of practice in back then!

My plugs were really rich, but I had been babying the CJ along for a while, trying to diagnose the problem.

Last time, I tuned it using a vacuum guage, and had great luck. Plugs were burning pretty nice. Now, with the carb running even better, it should be easier to dial in.

When I drove my CJ to Moab a few years back, it ran great through CO. The higher the elevation, the stronger it seemed to run! (well, up to around 9K, then it started suffering some:snorkel

I park the CJ during winter (Texas rig, never seen a MN winter yet!) so I was hoping to have it running nice for the summer.

Ended up driving my 'new to me' TJ more, and didn't do much with the CJ. Now I rolled the TJ, so it's deadlined for a bit, and I only have about 2 months left of driving the CJ, before the snow and road salt start flying, and it goes into hibernation again.

I was towing my M416 w/RTT, and was loaded down with tools and spare part plus gear for 10 days.

 

[Metcalf]

When I drove my CJ to Moab a few years back, it ran great through CO. The higher the elevation, the stronger it seemed to run! (well, up to around 9K, then it started suffering some:snorkel

Was this with the power valve possibly not working? I can't imagine the jetting was THAT far off. It could have been leaning out at altitude without a working power valve...that could explain why it felt like it was running better.

Is the engine modified at all. What size 2100 are you running?

 

[Metcalf]

2.6:1 low range planetary 'underdrive' that I am modding to fit on the back of the Dana 18 transfer case.

They aren't small, that is for sure! No effect on driveline length, which is nice for my 85" wheelbase. The gearbox lives behind a V8 in stock applications, so it should be fine behind my V6, even the more stout one I have planned for the future.

This will give me an the stock 2.46 low range in the transfer case PLUS an additional 2.59 low range when I 'need' it. With the planned 4.88 gears ( in the diffs ), and the new T18 transmission I have going in, this should give me a 196:1 low low range option. Needed...probably not...fun.....for sure! I do think that the ultra low range has its place in deep deep snow, technical rock, etc. Sometimes ultra low gearing works....sometimes it's a total waste.

It's a fun project a friend and I started thinking about years ago....should be neat to see it finally happen.

 

[postalWagon]

COOL, that looks like fun to mate up.
Did you need to make an adapter plate?

 

[Metcalf]

yeah....need to make a few things...

There will be an adapter plate on the back of the D18 that bolts to the PTO port and provides the underdrive bolt pattern. This will also function to separate the fluids of the two cases. Provide a front seal for the gear box. It will also provide a bearing pocket in the front.

I have to make a new 'transfer shaft' from the stock 6-spline jeep output to the 10-spline underdrive input spline. This is probably going to be made with a SAE-B 1.38 6-spline coupler and a cut down TH400 output shaft.

I have to add a shaft collar and spacer on the transmission output shaft to hold everything in the right place.

Then the complex part. I have to make a new Dana 18 input gear that is adapted to the underdrive. The power basically comes from the underdrive on the back side of the transfer case. The input power goes through the middle of this also. I am going to use the factory QT upper drive sprocket that will be turned down and an Advance adapters overdrive planetary gear. These two will be turned, bored, hot/cold fitted, and TIG welded together. I will be using to tapered roller bearings to trap this new drive gear assembly. The PTO adapter plate will be shimmed to provide correct bearing preload.

Not simple, but not THAT bad really.

 

[Hill Bill E.]

Was this with the power valve possibly not working? I can't imagine the jetting was THAT far off. It could have been leaning out at altitude without a working power valve...that could explain why it felt like it was running better.

Is the engine modified at all. What size 2100 are you running?

As far as I know, the power valve was working then. It was a fairly fresh rebuild on the carb. The carb is a 1.08 venturi

The motor was a fresh rebuild also, only 7K miles on it when we headed out for Moab.

It was bored 30 over, and had an HEI dizzy, other than that, all stock.

Could very well have been the fuel. I have noticed that all my rigs run better/get better mileage once I get south/west of home, as long as I stay away from that 'corn gas' :snorkle:

 

[Metcalf]

What could it be........

 

[postalWagon]

DANA 20 t-case or lots of gears

 

[Metcalf]

nope....I have all my t-case stuff

 

[postalWagon]

Transmission?

 

[Metcalf]

Bingo....