dating a CJ

[Otto R]

I believe i have an early CJ3A from the information i gathered on this website.� The jeep has a model 41 axel however the prior owner registered as a 47 cj2a.No Vin Tag on the firewall.� I'm Looking for some other ways to date my project.� I have a 1949 Harrison heater and older style horn button.� My motor has a serial number R3J177644 and appear to be a later model? Can any one tell me what year is the motor?� What does the R stand for?

[1955CJ-5]

Did you see this?

http://www.cj3a.info/cj3a/date3a.htm


And a quick way to check your tub is to measure the top of the wheel house behind either seat. A 3a measures ~32" and a 2a is ~34"...

Pictures really help....did you just get this jeep?

[Jesse]

Well typically when I'm interested in dating a cj I get to know it before hand so I have a good idea of what it might be interested in. It's also very important to be polite to parents and friends, as they have a big influence as well.


Upon further review of your actual question I realize that maybe I provided the wrong advice... I'm thinking that if it really is an early 3a you will be able to find little parts here and there that they were using up from 2a models. Bob W has a really good grasp of these things, maybe ask him if there are any such carry-over parts commonly used to look for. The engine could just be swapped in at a later date, so don't get really hung up on using the serial to pin down the jeeps build date.

-Jesse

[Gunslinger]

Jesse, is it proper to hold the steering wheel on the first date...?

I have an early 3A, couple things you could look for, but as always these are just parts and could have been swapped out along the way. 
Dana 41
Hood blocks are not symmetrical on 2A hoods, measure from the seam in each direction if they are different its a left over 2a hood
Radiator mount, 3a is a bottom mount 2A is on the side
Look for support straps inside the engine compartment running from grill to firewall diagonally, 3A does not have them
Front Axle, the bell crank on a 2A is mounted to the Axle, not the frame, 3A Bell crank is mounted on the round cross member
Measure the distance in the cab for the driver to sit in, Bob W has the dims, but the 3A is about 3 inches longer than the 2A in the driver compartment.

3A looks better, drives better, goes faster and jumps higher than the 2A, hope that helps.
Gunslinger

[Mike S]

I have a 1947 CJ2A - the bell crank is mounted to the bottom of the front cross member... in fact, every unaltered one I have seen is that way. The early 2As have a 3/4" diameter bell crank shaft, later ones, and I think CJ3As, have a 7/8" shaft.

[garage gnome]

It is quite easy to date a CJ. They like 4 wheeling, LOVE oil and gas and a good scrubbing behind the fenders. Long drives are good too. 

[Jesse]

Mike is right, a GPW had an axle mounted bell crank. I think maybe 2a had taper bearings and later jeeps had something else in the bellcrank, or vice versa. Early 3a might have a bottom mount radiator. Good call on the hood blocks Gunslinger, one is 13 inches from the center and the other is 10 1/4in. Your body wheel tub length is probably going to be the giveaway here. Steering shaft from a 2a is shorter as well.

As for holding steering wheels as soon as you see the cj, don't do it or you will want to buy the project.

-Jesse

[SteveW]

The R is a replacement engine. With regards to the year, lot's of things can happen over that long a time period including title swaps so the few can't change differences from 2a to 3a are what you need to go on. Both my 50's have 41 rears.

[p3ferris]

You guys are mean, because you all beat me to all the smart remarks.  Although we know he was dateing the cj I was wondering if he was going to ride......no I had better not sat it.  Not on a first date.

[Jesse]

Don't listen to P3ferris, he doesn't even drive a jeep. I'm really not one to talk about correct details since I smacked together the coolest features of like 6 jeeps. I'm shutting up until Bob W chimes in.

-Jesse

[athawk11]

�R� normally stands for �Replacement�.

In addition to above info�

Frame horns, where the front bumper attaches, are part of the frame on a 3A.� This is true on a few late 2As and all 3As.� On a 2A, there are bolt on gussets between the bumper and frame.�

3A frames have offset motor mounts.� 2A motor mounts are in line.
�
3As have no provisions for storing top bows.� Most 2As originally had brackets welded to the driver side.� Some 2A �Lefties� had these brackets welded to the passenger side.�

An early 3A will have a frame mounted radiator just like a 2A. A late 3A will have a side mounted radiator.

2A and 3A windshields are very different, but these are direct swaps.� Generally, this is not a sure way to date your Willys.

These are a few ways to determine a 2A from a 3A.� If you find you have a 3A, there are a number of ways to figure out what year it is.� That�s when it gets fun.� Bob Westerman�s book is invaluable for this type of research.� You may be able to get it down to the month it was made.� Maybe even the week.

Post some photos too.� This will really help us with your quest.

Tim

[F Bill]

One sure fire way to tell a 3A frame is the offset motor mount location and the lack of separate bumper gussets.

Measure your wheelhouses to decide if the tub is 2 or 3.

All the other details can help narrow down the year.

It is getting so there are a lot of salad jeeps built from piles of parts from several different jeeps so you might not be able to narrow it down, especially if you have a mixed 2A tub on a 3A frame or vice  versa. Some guys will build a jeep, then buy a data plate and call it whatever the data plate says it is, and title it using the totally unrelated data plate. If you have one of these, just enjoy it and try to figure out the individual parts as you work on them and need replacement stuff.

And all the jeeps I have dated followed me home, so be careful with the dating thing. 

[Bob W]

My motor has a serial number R3J177644 and appear to be a later model? Can any one tell me what year is the motor?� What does the R stand for?

Looks like someone put a different engine in your Jeep. Most R3J engines I have seen were in stationary power units, like generators and welders. I think brand new complete CJ-3A engines could have been purchased at Willys dealers and they would also have an R3J prefix. Your engine probably has casting number 908756 so that would make it a late 50's or later engine. As mentioned, photos of your Jeep would help us ID it

[Otto R]

To give an update! I pulled my motor and will be replacing the clutch, flywheel and painting the motor.� Much to my dismay the motor was stamped 1955 on the fly wheel.� I will try and post some pictures of this. So far i replaced the gaskets on the manifold oil pan and timing gear cover. The radiator was tested and held 14psi so i also add a 180D thermostat.� All new plugs 12v coil and wiring harness. I also replace all brakes, fuel lines and fuel pump.

[1955CJ-5]

Nice Jeep!