Early CJ5 driveablity??

When my Suzuki Samurai was new I drove it 100 mph several times. Normally to prove to people it could do it, since everyone seemed to believe it couldn't. That was a fuel injected one which is light years different. The Samurai would maintain 85 mph easy, I drove it all the way from North Carolina to Texas many times going that fast the majority of the time. Favorite vehicle I have ever owned which is exactly why I bought the old CJ, it will be my daily driver when I am done with it.

But back on topic I often see that reaction when people say "white knuckle ride", ect and I am not certain why. If the Jeep is put together right, for street driving then doing 85 is nothing. I am not saying its altogether safe because the CJs have no crash protection built in, but that is another story. As far as driving down the road it is not much different to driving a truck or any other older vehicle. If put together to do it, they drive just fine. If built for off road then they will drive like they are built for off road. If slapped together with junk yard parts, by someone inexperienced and not giving it much thought - well results will vary. If you can make a 32 Ford drive down the road fine at 85 mph you can do it in a CJ5 also. For the record a 32 Ford has worse air resistance than a CJ5, just putting that out there.

I am still up on the air for drive-ability though. A huge factor, I believe is the area you live in. I live in Texas, and it is mostly flat here. My Jeep, completely stock with Fhead and 4.27 gears (+ OD) could easily cruise at 75 mph. In that regard I do not agree with general consensus that says putting in higher gears and OD does not increase the top end. Depends a lot on where you live and wind resistance is not nearly the big a factor people image.

My Jeep with the Fhead and no over drive, has a top speed of right at 60 mph. Not because the motor lacks power, but because of the RPMs. With the over drive it could can be pushed up to around 85 mph but cannot maintain it. It can maintain 75 mph easy though. The speed limit on the Interstate is 75 mph. To go to work I need to drive 40 miles, 20 miles of that on that Interstate. My Jeep in its current condition could not reasonably do that. With a V6? Yes easy and it will. Could it be made to work with the Fhead? I am not sure, maybe. But, I think the gas mileage would be bottom line for me. I don't think the Fhead could be made to get good enough mpg at that speed to be considered a reasonable daily driver.

It also depends on how you define daily driver. We have discussed this before. If you drive 5 miles or less to work, on city streets and basically just have to cruise around then just about ANYTHING could qualify as a daily driver then. Even a riding lawn mower. If you are the average American and drive 20+ miles to work, including interstate and highway time then it becomes much more complicated and the amount of people you will find using an old CJ5 as a daily driver will be greatly reduced. There will still be some but a lot less.

So what do I think you need to do to have a daily driver on an old CJ5?

Seat belts, better windshield wipers (or at least fully rebuilt vacuum ones), good springs, either a brake upgrade or 9 inch ones in top shape, steering fully rebuilt or replaced with an upgrade, stock size wheels, a top of some kind - and better gearing. Neither 5.38's or 4.27's will work on their own for a daily driver that gets used on the interstates. I will never agree that Fhead needs the 5.38's for street driving so I am going to say the 4.27's are better all day long. I swapped mine and have never looked back - it is like my Fhead gained 30 HP. But, it never once had any problem driving up to speed with either gear set. The only difference was the RPM's - for me the 5.38's are simply to low. If I lived in an area with hills or mountains I am sure I would be singing a different tune though. My Jeep does fine on moderate hills with the 4.27's but the OD is pointless in that situation. On flat ground? Huge difference.

For me the list of must haves are:

Seat belts
Gearing change (either 3.73s or OD)
Stock size wheels

The wheels are probably the biggest factor on a daily driver. If you go very big you increase the rotating mass too much and the Jeep will seriously lose top end despite the better gearing. I honestly think this is why so many people believe the gearing change does not help - I have this idea that most people who say that are running 30+ inch tires and trying it. Anything over 29 inches and you really start noticing the difference if you are running an fhead.

I run 235/75/15s on mine and just the little extra weight from the width effects it some. I prefer it though because they are much better street tires.

You see a lot of people say steering and brakes, but what came on the Jeep can be used if maintained. That is a problem though because the 9 inch brakes will stop slower that a normal car and the Ross steering wears out so fast its hard to keep it in good shape.

I have swapped my Jeep to 11 inch brakes with a dual master. The steering is stock and not really that good after 65 mph, but mine is seriously worn now and needs a rebuilt. I have a full postal Jeep Saginaw setup that just needs to be put on. I took my brakes off a 79 Wagoner that was scrapped.

So that is my take. It is different than the general consensus you will find on these forums but I don't really do consensus. If the conditions are right you could drive a fhead Jeep as a daily driver but speaking from experience I think a V6 Jeep would be better. That or at least a Jeep with a more efficient engine such as a Ford Ranger engine. Still a 4 cylinder but they do great as Daily drivers. Originally I as going with that swap for mine Jeep but a rebuilt Chevy 4.3 fell into my lap and I decided what the heck.

Another though. You can fuel inject the fhead using a mega squirt and it makes a huge difference to the way the engine runs, you combine that with an electronic ignition and the engine runs pretty well. It makes more power than stock and the response is very different. But you still have the same problem - the RPM limit of the engine. Just a thought.

 

I can share my experience in upstate ny with a bone stock early 4cyl cj5.
The engine won't last long between overhauls on the highway too much rev and load. There also is no help when you hit a hill you just have to bog down to 3k then get to 2nd overdrive if you have it... brakes are also a good investment. Any electronic ignition the constant rain humidity arn't good on points. I only one car my cj5 for 5years untill I had to rebuild or swap engines and that time was spent between NY and MO I would take the 4 lane in a 4cyl over a 2 lane where there is no place to pass.

 

My Jeep is set up like this and it works out great. I am going to add some caster to the front end and drive it more.

 

Well, I'll tell you, around here you could possibly use the ECJ with F-Head 4 cylinder as a daily driver on the freeways at rush hour. Both morning and early evenings. Mainly because traffic is so thick on the freeways that nobody gets above 50 mph, and usually only up to 35 mph or so. Me, I would leave earlier and take the scenic routes with my ECJ, because I am not in that much of a hurry.

 

Hi Mike, Rick Whitson here. I have a 1964 CJ 5 Tuxedo Park with 134f head motor. The Tuxedo Park was a combination of several different Willys parts. They were CJ5's with a DJ Column shift Transmission, different second gear ratio, and 15" wheel and tires. Tuxedo Parks came with 4.27:1 axels where stock was 5.38:1. That made the Tuxedo Park more street friendly. I put 1966 CJ 5 axels from a V 6 in my Tux, that give it 10" brakes and 3.73:1 axels, and it can cruise at 50mph easily and it tops out around 60-65, fast enough for a CJ 5. Early CJ's were a tractor for the street they were not meant to go at freeway speeds, I have had mine sideways on gravel roads at 35-40 mph. They are so short they will spin out even at slower speeds, how many cars have you ever drove where you could touch the back tires while driving it. I took off the 8.5" Ansen's and big tires, and put on some 7" Ansen's with stock size tires and it drives completely different, a lot better. My Jeep does not like long slow hills though, it slows down for lack of power. good luck what ever you do.

 

I have a couple hundred thousand miles running various CJ's on city streets, hi-ways , and interstates.
I've run those miles on everything from steep down hills, through the flatlands and up steep inclines.

In stock form the short wheel based CJ's (80" or 81") will not feel very secure at speeds over 65 MPH !

The other major concern is the final drive ratio (FDR ) along with the engines maximum efficient RPM.
The maximum efficient crankshaft RPM is identical to the RPM at maximum torque output.

Only the 134 engine and the 5.38 FDR was installed prior to early 1963.
4.27 FDR was standard on 1963-1971 CJ's with Hurricane engines.

The maximum efficient RPM for a Hurricane is 2200 RPM.
Not nearly as efficient but I will recommend an absolute maximum sustained RPM of 3100.
Beyond that RPM the Hurricane engine MPG and longevity suffers horribly.

With standard 29" tall tires the pre 1963 CJ's will optimally cruise at 35 MPH.
The maximum sustained speed is 50 MPH.
Those with 4.27 FDR optimally cruise at 45 MPH with a maximum sustain cruise suggested as 63 MPH.

Add a 25% O.D. and the optimal 5.38 FDR cruise speed increases to 47 MPH with a maximum sustained speed of 66 MPH.
Willys did not authorize the Warn O.D. to be used with 4.27 FDR.
The Hurricane simply does not have enough power to use that high of gearing with any efficiency.

On steeper interstate grades requiring an additional truck lane the Hurricane engines are pushed to their limit with 5.38 FDR compounded at 25% overdrive.
On these grades expect that a strong running Hurricane with optimum gearing may be hard pressed to maintain 50 MPH at wide open throttle (WOT).

The 5.38 FDR with 25% OD provides maximum possible efficiency for the small 134 engines.

If running a Hurricane engine then I recommend 4.27 FDR with out an O.D. unit.
But much better yet I suggest you run the 5.38 FDR with a 25% O.D. unit.

Understand that the 134 engine is not up to snuff if you hope to have reasonable efficiency and speeds near 65 MPH.
A larger displacement engine with slightly higher RPM band is notably more efficient than the F-134 engine.

 

X2. slow down and enjoy!!!

 

I second that emotion.

 

That's a fine sentiment but not always possible or realistic!

 

My '60 cruises very well at 50 mph and about 3100 on the tach. I get 17 mpg doing it. Which is the best mpg these beasties are capable of, anyway. No overdrive.

 

I agree with Oldtime... my 1966 stock CJ with a F134 and Military NDT pie cutter tire on 16 rim (30" I think) drives ok at 55 mph on the flats with no wind but you can tell the engine is much happier just a tad below 50 mph. It really doesn't like long hills and although Oldtime said no overdrive was ever approved - climbing a hill is the only time that I'd would really like to be able to split the 2nd so that I could reduce the RPM. As far as top speed in 3rd with an overdrive, I can only see benefit at reducing the RPM to save the engine when the condition are ideal as oppose to "dream" of a faster top speed.


I briefly looked into the diesel kubota swap since the company making the adaptor is close to my place but I gave up the idea pretty quick since my old CJ is original and not cut up and would hate to see it changed.

 

The Warn O.D. was designated as "JEEP APPROVED SPECIAL EQUIPMENT" by Willys Motors in September of 1964.
But it was only approved for Jeeps with 5.38 and 4.88 FDR and not ever approved for higher FDR's.

I imajine that 4.27 FDR for Hurricane CJ's would have not become the standard FDR in early 1963 if the Warn O.D. was available just 2 years earlier.

 

"In stock form the short wheel based CJ's (80" or 81") will not feel very secure at speeds over 65 MPH !"

I guess that depends on the person. I do find it funny because you see people say that a lot on CJ5 forums but almost never hear someone a Suzuki Samurai forum even mention the wheel base. A Suzuki Samurai is shorter and feels just like a car at 65 MPG. I did well over 300,000 miles in those (I had 4 of them) and I drove them 75-80 MPH on a regular basis. I also drive my current CJ5 60-65 mph and aside from the loose steering it is fine. 75+ it does not feel right but that really has nothing to do with the wheel base for me, it is the center of gravity and springs that are too soft that get to me. I am going to remedy all that and once I have done so I assure you I will be driving it 75+ on a regular basis.

"Only the 134 engine and the 5.38 FDR was installed prior to early 1963.
4.27 FDR was standard on 1963-1971 CJ's with Hurricane engines."

My Jeep came stock with a 134 engine and 4.27 gears that is a fact. Currently my Jeep is 100% original excluding the brakes that I have swapped over and the more modern mirrors I put on. I have never been able to 100% positively determine the year it was made. I believe it was built in 1962 and titled in 1963. If we say it is a 1963 then that lines up with the statement above.

My CJ is an import model and also came with a few odd things like a split window like you would find on older M38A1s.

Just curious but why do people on these forums use the term FDR when referring to the axle gears? I realize they mean final drive ratio but seeing as the FDR would change in a vehicle with a transfer case, and only be equal to the axle gears when in high gear 1:1, I find it odd.

 

Gosh I wish that Suzuki Samurai was an American vehicle...I would be all over it...just mount my 1948 CJ2A sheetmetal on it...something that would run with modern day traffic flow but still be cool as heck on the outside too...

Why cant some American car manufacturer build a Suzuki Samurai???....now that would be cool...

Kinda sounds like a lot of work to make a flat fender resemble anything that will be ok to run down the road with current day traffic patterns...a lot of money too...

MikeC

 

The 80 and 81" wheelbase is merely a means to identify which CJ's have the questionable handling characteristics.
The driving characteristics of those jeeps are also effected by the suspension, axles installed and the steering components.

See: http://cj3b.info/Photos/Tech/ServiceBulletins/SB601AxleRatio.JPG

FDR is not a widely used term.
Yet it is a term that I frequently use to identify some of the gearing variables.

The transfer case gears simply are not the final drive.
For a jeep the final drive itself is the rear axle assembly.

The FDR is compounded by the transmission, the O.D. and the transfer case to create all of the available ratios between the cruise ratio and crawl ratio.
All of those various available ratios are the topic of "Gear Ranging".

"Gear Ranging" is a compound study and ultimately it need be understood along side "RPM Ranging".

 

The Suzuki Samurai is modeled directly off the Willys Jeep. There is a guy that did swap his CJ2 or CJ3 onto a Samurai drive train.

I have not messed with the flatties to much but I suspect they would be a little harder but not loads

 

I responded to the part that said short wheel base. A Samurai is very similiar in its handling characteristics btw.

Jeeps are not unique and get to make up the definitions of things. Final drive ratio is the, well final drive ratio. It is the gear ratio that is applied to the wheels when all other components are engaged. So if the transfer case is in 1:1 and the axle gears are 4.27 so long as the transmission is also in 1:1 the FDR is 4.27. Change gears, on the transmission and the FDR becomes something else. That is why I brought it up. Your reasons for using it may be different that others but I see a few people using the term

 

Kind of why I asked Glen. So lets say for example we use FDR for the axle gears - now what do we use to describe the ratio that relates to being in High on the Transfer case, but in 2nd gear? I ask because that term becomes relevant when we are trying to work out things like RPM at certain speeds, ect

So just for the sake of this site, what would people use in that scenario? I am game to play along

 

Doing the math, if I didn't screw it up (being ancient and retired, it is entirely possible) the overdrive drops the engine and tranny speed by 25% or so. If you take the 5.38 fdr of a stock 4 cylinder ECJ at 1:1 for both tranny and TC and figure a 25% drop on that, it works out to something like 4:09 or 4:10 or even 4:11. Swapping in 4:10 or 4:11 gears, which I believe are available for both the D27 and D44 diffs, you get the same thing. You get a vehicle that will run 60-65 mph and will still do very respectable off-road crawling around. And less wear and tear on all of the drive train components. However, I would still stick to 50 or 55 mph in mine. Because that is what I am comfortable with.