Building a CJ-2A

[Root Moose]

Oh, and regarding transfer case and transmission. There is a T-90 that was used in the pick-ups that has a slightly lower first gear. If you end up rebuilding your existing T-90 it may be worth doing that conversion at the same time since it is all bolt in (IIRC).

The Dana 20 case would be worth doing if you have the case apart as well. I don't think I'd bother adding lower transfer case gears given your intended usage - unless you really want them anyway.

Buddy of mine (Mudlite @ OVO) has a M38 with a Toyota drivetrain in it (22R and Toy/Aisin transmission/transfercase and axles). Nice machine. It will all fit if you decide to go that route later on. I don't know if I would do that though. The Studi engine sounds like a "period correct" restomod - I like that. Sort of a 4x4 rat rod approach if you follow what I'm saying.

 

[ntsqd]

No, you missed my point. For what he wants to do any old springs will do. As will any old shocks. He's not building an extreme rock crawler. Sure it might be nice to have that stuff, but I got the impression he was trying to do this on a budget.
You don't need extreme articulation to conquer 99% of the trails out there.

Again, you've missed my point. I wasn't suggesting a rock crawler suspension, I know very little about such suspensions. I was suggesting a suspension that would be comfortable for long drives. Short, stiff springs and cheap shocks are sure recipe for a sore back in a short distance. "Any old springs" will not do. If it is not a pleasant experience to drive then it gradually will get used less and less.

The proposed Rancho's may or may not not work well for the use. Depends on how many leaves they have and how much arch each leaf has, and if they have tip sliders or not. If they do not have tip sliders I would highly suggest a thin piece of polyethylene (McMaster-Carr is one source) between each pair of leaves. Getting the internal friction in the spring to the bare minimum will increase the suppleness of the spring and make them ride more pleasantly.

The shocks do not need to be 4.0" diameter quadruple by-pass units. Just a simple, non reservoir 5100. One sample of on-line pricing. As it happens 5100 out of the box valving is set for leaf springs. I've hammered on a set of these for 4 years while chasing desert racers and on many exploring trips.

I don't see any advantage in lower gearing, be it in the trans, transfer case, or axles. A 2A will already have a fairly low axle ratio. Having driven 3 speeds I know that they work, but they are not fun to drive because there never is a truly correct gear. More speeds makes the drive more pleasant and less distracting to drive. If it is difficult to drive then you can't enjoy where you're going.

The transfer case mods that I suggested were for durability more than anything else. Dana 20 and Dana 18 transfers share the same internal dimensions. Can drop the guts of an 18 into a 20 case or vice versa. Since all of the power flows across the idler shaft all of the time, using the latest, strongest version is important. There is/was a tapered roller bearing conversion out there for the idler, but I suspect that the cost would be out of the budget. Jack O'Brien (sp?) I believe used to offer this conversion.

I'll second going to Saginaw steering, power if desired. Loose a bunch of monkey-motion and gain a good, strong steering box in the process.

I'd be very cautious about putting any sort of locker in those axles. First off, they're old. Fatigue has had a go at the axle shafts. They are also likely to be square spline rather than Involute splines, which are considerably less strong. Those two issues coupled together with a locker sound like a disaster in the making to me. I'd say drive it the way that it is and if/when you decide to go with a TAD of any sort that you need to upgrade to a later model axle at the same time.

 

[Root Moose]

Have you finalized on a tire size yet? 31" versus 32"?

Does that Jeep have 16" wheels? Just thinking a good compromise may be to find some used MT/Rs off a Rubicon that someone is upgrading. 245/45/16 is ~30.5" - or roughly the same as a 31x10.5x15 when you put a tape measure on it. Not sure if those OEM wheels can deal with the width though.

May be an opportunity to switch to a wheel with a little less backspacing, get the edge of the tires right under the front fender edges. a 245mm wide tire works out to ~9-3/4" wide tire. Would be a little less aerodynamic and rolling drag while being "wide enough" compared to a floatation sized 31x10.5x15 or 32x11.5x15.

JAT (just a thought)

 

[Metcalf]

Did someone say flat fender?!?!??! :wings:

I've 'wheeled this little guy for a while now, something like 6-7 years. I daily drove it for a few years, took it to college for a bit, did some 600 mile trips in it, 'wheeled it in Moab, and generally used it like it should be used.

The specs on mine are...

1942 Willys MB frame and body
225 Buick Odd-fire v-6, Hei, Holley 2bbl, GM alternator, Optima battery
SM420 granny 4-speed, cable clutch linkage
D18 t-case with twin stick and custom 1/2" adapter
D44 rear end, 4.30 gears, Powr-lok, small drums and 2pc axle
D27 front, 4.27 gears, open, disc brake conversion, vintage locking hubs
32x10.5x15 Swamper Radials
Stock springs with small shackle lift ( 1" max )
Power steering conversion
Hanging pedal conversion
GM column and small pimp steering wheel

I think you have a pretty good idea overall, it does take a pretty specific kind of person to want to travel around in an old Willys jeep.......

My ideas for you.....

-Cooling. Get as much cooling capacity as you can for your little jeep. Mine is right on the edge with the tight engine compartment and V6 when I really push it or when temps are in the 3-digits. I had to go with an electric fan for packaging concerns, and it works pretty well, but for simplicity I would go with a mechanical fan system, tight shroud, and as big and thick a radiator as possible. I would also suggest finding a way to get some heat out from under the hood. The engine compartments are pretty tight and getting the hot air out is always good. You can see the back of my hood propped up in the above pic.

-Engine. You don't need a ton of power, but you need reliable and simple power. My ideal engine choice would be a 1.9L VW TDI engine converted with a mechanical injection pump. I think this is compact enough for the flat fender jeeps, plenty of power, good rpm range, fuel injection like performance without the need for complicated pumps and tanks.

-Transmission. You want gearing. A granny 4-speed is GREAT in these little jeeps, especially with the little motors. Being able to slide it in granny low and creap over, down, or up stuff is pure bliss! Mine is geared just about right for anything. If you don't want to swap out the transmission look into the Tera 3.15 gears or the transfer case.

-Overdrive. While the overdrive is nice its not neccessary once you accept your driving a 60 year old jeep. 45-50mph is fine. Mine will go a lot faster than that and I just don't like the abuse. Just find roads you can go slow on. Most people respect the old jeeps and don't give you many problems.

-T-case. As long as you don't have the smallest intermediate shaft D18 you should be ok. I don't have the biggest shaft and have never had problems. The D18 is really a stout little case! In an ideal world I would like to have front wheel drive only as an option...but with the short wheelbase its not a big deal. A disc parking brake is also on my wish list. Again, if you don't do the granny transmisison think about the 3.15 low range kit.

-Rear axle. The 2pc axles kinda suck. I would suggest a full-float kit for the rear axle. If you do it right you can have matching front and rear hubs, bearings, discs, etc. Less spare parts for sure. The D44 is strong enough one you get a full floater kit in it. The old D44 19-spline powr-lok diffs are pretty easy to find if you need some more traction.

-Front axle. If you can, swap in a narrow track D30 front a slightly newer jeep. Discs and open knuckles would be nice. It just about bolts in. For anything under a 35" tire this a GREAT upgrade for these old jeeps.

-Suspension. Buy great quality springs. These old girls are back breakers with the short wheelbase. I would suggest going to someone like Alcan, Deaver, or National and get a full custom set of springs that bolt into the stock locations. This will make a PHENOMENAL difference in the ride quality on long dirt road trips.

-Power steering. Its really really really nice to have. I would suggest doing the 'Herm the overdrive guy' style swap with the steering box behind the radiator crossmember and forward facing box/pitman arm. Again....really nice to have.

-Disc brakes. I wouldn't worry about power disc brakes, but disc brakes on all 4-corners with a good manual master cylinder will make the jeep much safer on the road. Stopping is not a strong suit of the original system.

-Tires. I think the ideal tire size for these old jeeps is a 34x9.5 or 34x10.5 tire with only about 2-2.5" of lift. Keep it as low as you can. The short wheelbase doesn't need that much extra height before it starts to act a little funny. The extra gound clearance the larger tires provide is very nice off-road. The extra height also brings the RPMs down a bit on the road.

-Resist the urge to hang a bunch of stuff off the rear of the jeep. Pack lighter and keep everything in the rear tub. You will get MUCH better performance and handling this way.

Enough for now......

Get out and have fun.

 

[craig333]

If you go with a 4 spd transmission you'll have a really short driveshaft. Careful with the angles. What gearing do you have now? I have the 5.38s in my Jeep and even with an overdrive I'm hesitant to push it over 55.

 

[Metcalf]

I have a 19" driveshaft in my flatty.

I did my own adapter for the sm420 to D18. Its only 1/2" thick though. The input gear is a 2wd yoke with the od turned down and a bored out D18 input gear TIG welded together. Its tight, but even the stock shifters on the D18 fit.

 

[Ian]

craig333 - The gears are 5.38s.

Metcalf - I have done some work on this baby already, including replacing the original sieve-like radiator with a brand new 3-core one. Thanks for all the info - you've got a great looking machine there. :Wow1:

Root Moose - The engine is a 1950 9G Champion. Six cylinder, 169 cubic inch, 85hp @4000rpm. I've got a repro factory manual for it, so I can rattle off any other stat you want to know. It barely fits in the engine compartment, but since Studebaker Champions used T90 transmissions it bolts right into the rest of the Jeep drivetrain.

 

[Root Moose]

That sounds pretty cool. I'll Google the engine and read up.

The fact that it was factory matched to a T-90 makes it a match made in heaven in my opinion. To be really nerdy you could try fangling a GM or Megasquirt TBI EFI.

EDIT: so reading up looks like you get ~138 lb-ft of torque with that engine. Niiice!

It's a flat head engine like the Go-Devil, eh? Can you snap a picture or two for us?

 

[craig333]

I have a 19" driveshaft in my flatty.

I did my own adapter for the sm420 to D18. Its only 1/2" thick though. The input gear is a 2wd yoke with the od turned down and a bored out D18 input gear TIG welded together. Its tight, but even the stock shifters on the D18 fit.

Making your own adapters? No wonder you managed to have so much length. Wish I was so skilled.

 

[Ian]

I just happen to have a couple engine photos already on the computer...

Happily, I've found a good source for pretty much every engine part used in this thing. There's an older couple in Phoenix who run a Studebaker parts shop out of their house, and I've already dealt with them for a few things. Very nice people, and they've got everything I need to do a complete rebuild on the motor.

 

[craig333]

So nice to see something other than a 327 shoehorned in. Can't tell you how many people I know stuffed a V8 in a stock Jeep. Of course three things happen. 1. Its too nose heavy and handles funny plus its just plain squirrely. 2. As soon as you get offroad it overheats. 3. As soon as you gas it parts break. Of course number 3 may happen before 1 or 2.

Then they either spend way more than planned upgrading transmission, axles etc, or it sits in the garage for years.

I readily admit its partly the money that I still have the F-head but its also practical. Doesn't overheat, has good torque off road and leaves room under the hood. But its also the reason it gets towed most places :sombrero:

 

[craig333]

Interesting. Has the bypass oil filter and a generator. Like a go devil on steroids. Bet it originally had the oil bath air filter too.

 

[Root Moose]

Very cool. I'm not so up on this particular vintage stuff that I can't say it doesn't look like a 6 cylinder Go-Devil to me. I bet it even makes the same sort of sound.

Very cool - I'd keep it for certain.

 

[ntsqd]

That 6 doesn't look a whole lot longer than the original 4 cyl. Longer for sure, but not by a lot.

With the 5.38's would you need the deeper gearing of the longer truck type trans' deep first gear? That is partly why I was suggesting a passenger car type 4 spd. Keeps the package shorter and offers more actually usable gears.

On the alternate engines idea (Not that I think that a swap should be made, I too like the Stude 6), the two that have made the most sense to me were the 4.3 GM V6 and the 151c.i. GM 4 cyl. The Toyota parts work, but those trans & transfer combos are really long.

 

[Root Moose]

Yeah, I'm leaning to your line of thinking. With the Stud engine he has a lot of torque to somewhat compensate for the "lack" of lower gearing.

By truck transmission are you referring to a SM420/465 or a Willys T-90? I wasn't aware the Willys truck T-90 was longer than the Universal or car T-90. I'm not totally "up" on these beasties though. I thought that externally a T-90 was a T-90.

If there is no need to muck with the drivetrain due to engine selection (avail torque), maybe just run everything as is. At a later time investigate the 3.15 t-case gears. Easy swap that requires no drivetrain components moving and it is not a "crazy deep" low range like say 4:1 or similar. If you are replacing gears due to wear anyway I'd really look hard at the 3.15 gear set and the roller bearing upgrades all the same.

$0.02