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Uncensored Jeep Nudity: The First Stripped CJ-5 Chassis

Posted in Features on November 29, 2016
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When the CJ-5 was introduced on October 11, 1954, it was a pretty big deal for the Jeep line and the start of a 28-year production run. Had not the Korean War occurred, it’s nearly certain the CJ-5 would have debuted in 1952 at the same time as the M-38A1 military version and by 1953 at the latest. By this time, Henry J. Kaiser’s financial empire was more than a year into running the company, having finalized the deal with Willys-Overland (W-O) in April 1953 to create Kaiser Jeep.

The lead-up to the round-fendered CJ started in 1949 with the development of a new engine. Both the military and civilian markets were calling for a higher-powered Jeep. The ever-conservative Willys looked for a way to do it on the cheap. That made it an ideal project for the legendary Delmar “Barney” Roos, who was still on the W-O payroll as chief engineer and a master at “on the cheap.” He was the principal engineer on the development of the WWII jeep and also the guy that turned the wimpy 48hp Willys Whippet four-cylinder engine into the legendary 60hp Go-Devil in just a few months. Roos had done engineering work in England and was exposed to the F-head style engines popular there. He found it exceedingly easy to “F-up” the flathead by designing a new overhead-intake-valve cylinder head. Very little new tooling was required, and many of the old flathead parts carried over. On top of that, there was an almost 15hp gain in power due to the improved breathing. Cheap and effective! What’s not to like?

The next step was a fresh wrapper for the new engine. The F-head had debuted in the ’50 1/2 Willys trucks and Wagons, where the taller engine fit with few alterations. The hood on the CJs was a little too low, and because it was about time for a stylish new CJ anyway, Willys began development of a new body originally intended to be for both the military and civilian markets. The styling transition from flat to round fenders is an interesting one in itself, but we’ll save that for another time. Suffice it to say, the new body was done by late ’51, but the Korean War put a civvy version on the back burner. The new body debuted as the Willys Model MD in ’52, called the M-38A1 by the Army. Civilians had to wait.

It’s a sliced and diced CJ. Just about every component has been opened up so the inner workings can be viewed. They also painted all the parts for the display. The chassis has suffered from the ravages of time and poor storage, but the current owner, Tremaine Cooper, intends a restoration at some point.

Ready To Reveal
A civilian model was in the cards and once some of the war-related material bottlenecks cleared up and Kaiser was firmly in control, the stage was set for the new Jeep. The 1955 CJ-5 debuted in three models, the regular CJ-5 (model prefix 57548), the CJ-5 Stripped Chassis (57648) and the CJ-5 Fire Engine (57048). Each of those models also had separate beginning serial number sequences that followed the model prefix and started at 10001. The chassis you see here wears the serial number 57648-10001, indicating it is the first stripped chassis CJ-5 built. There weren’t many others. The production list we have indicates a total of 10 built for the 1955 model year. For ’56, we find 12 listed, and it goes on and on into the ‘60s with a few built every year, but never more than around 100 at peak. The serial numbers are sequential from ’55 on, by the way, and didn’t reset. It’s clear that people were buying 4x4 Jeep chassis and putting coachbuilt or special bodies on them. What kind? We don’t know. There are any number of oddballs we have seen, but we can’t reliably connect all the dots just yet.

Even accessories such as the Koenig PTO winch, were opened up for viewing pleasure. When displayed, the chassis was on a set of built-on stands, and an electric motor drove the powertrain and engine via the transfer case.

This chassis is special. It’s obviously been prepared for display, with the components sliced open and painted to show the innards. It’s a fullsize “Visible Jeep Model,” for those readers old enough to remember the “Visible V8” plastic model of the distant past. The Visible Jeep was powered by an electric motor so that the power train would spin and make an exciting display.

Extensive research by Jp and some very notable Jeep historians has not yet shown us exactly how Jeep may have used this rig. What the owner does know is that it was built for display as part the marketing pitch for the new CJ-5. People in the Jeep history crowd have seen and identified images of this Jeep chassis at shows. Sometime after that, indications are that it was donated to the automotive department at the McCann Technical School in North Adams, Massachusetts. It was probably considered a cool novelty for a few years, but like a toy that has gone out of favor, shuffled off to a back room and forgotten, eventually going to a scrapyard where a foresighted owner kept it out of the smelter. It changed hands a few times and ended up with Tremaine Cooper who owns it now. You may remember Tremaine as the owner of the prototype ’44 civilian Jeep (CJ-2-06) we covered a few issues back (Nov. ’15). Tremaine brought the CJ-5 chassis to the 2015 Spring Willys Reunion in Hudson, Ohio, along with CJ-2-06, where it was publically viewed for the first time in decades. Eventually, Tremaine hopes to restore 57648-10001 to its former display glory. He plans to leave it deliciously nude, of course.

This serial number tag would normally be affixed to the firewall, but since a stripped chassis has no firewall, it was put on the chassis. The “57648” is the model prefix for a stripped chassis. Jeep always started its sequential serial numbers at 10001, so this is the Pure-D, certified, first-ever stripped CJ-5 chassis.

If you ever wondered what an F-Head engine was all about, here is a way to see it. The intake valves remain in the block, just like the L-head (flathead) design it was based upon, but the intakes are in the head and they are larger. It allows for a cooler and larger intake charge and is the primary reason why the power jumped 15 hp. The cam profile was altered to give the intake valve a bit more duration as well. The F-head design allows for a higher compression ratio without the associated breathing problems found with L-heads. The blocks are nearly identical between the old L-head and F-head. They are so much alike that an L-head can be converted to an F-head and for a short while, Willys sold a kit to do just that.

If you look carefully, you can also see a slice taken out of the top of the housing of the Dana 44.
The closed-knuckle Dana 25 was opened for viewing, and when the drive motor was operating, you could see the Cardan joint doing its thing inside the knuckle.
The opened-up Dana 18 transfer case can be seen here with an attached Koenig PTO. The strap keeps the electric motor from falling off after it broke loose in transit. The T-90 transmission was also sliced open on the side of the case.
Here you see the electric motor and gear drive. It was connected by chain to a sprocket on the front transfer case output and would slowly operate the powertrain and engine. To the right, you can see one of the stands for lifting the chassis off the floor. They are hinged to fold down and up against the U-bolt plate. The chassis is then either rocked back onto the stands or jacked up. The stands then lock in place.
The rear PTO, angle drive, and belt pulley are laid bare here. These products were less often seen on CJ-5s than they had been on the flatfenders, one indicator of the changing for Jeep in the American auto market.
The radiator and Koenig PTO winch are shown here. With the PTO engaged, the winch is rotating along with everything else. The cover is off the front diff as well.
A notable difference between the ’55 and ’56 (to serial number 444437) CJ-5 and the later CJs is the location of the front spring shackles. For that early period of time, Jeep offered the CJ with the shackle at the rear of the spring rather than the front. The M-38A1 was also this way. We won’t get into that ages-old debate about which is better, but it’s noteworthy that Jeep did it this way for a while. Were they crazy or inspired? You decide.
Just in case all this rampant Jeep nudity has taken your mind to a strange place, here is a CJ-5 with clothes on to bring you back to reality. And it’s a pretty neat CJ-5. This is a prototype and one of the earliest civilian CJ-5 adaptations. This image was taken in 1954, but the prototype probably goes back earlier. Note the “Willys” on the cowl. The production CJ-5 had “Jeep.” When Kaiser took over in ’53, it made plans to minimize the “Willys” presence as rapidly as possible. The first chance to begin was 1954, but through the rest of the ‘50s, all the Willys stamped parts were changed as old stocks were used up.

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