Mach 1 in a 3B?



How fast is it safe to drive in a 50-year-old CJ-3B, and what is the limiting factor? This was the thread started in late 2004 on the old CJ-3B Bulletin Board by "Chuck Yeager" under the subject heading "Mach 1 in a 3B."

It turned out to be one of the most popular threads on the board in a while, so I thought it was worth saving. When you're in the mood for some reading, maybe print this out and take it to the outhouse.

See photo sources at the bottom of the page.

Chuck Yeager: I had a to drive to another community about 25 miles away this morning. I took the '59 CJ-3B on the back roads over and the Interstate back.Thanks to the Warn Overdrive, I drove around 60 mph on the Interstate. Very smooth and stable!!

There have been discussions here in the past about the speed limit for a 3B. The comment back has been "The CJ-3B was only "designed" to do 45-60 max!"

I am not planning on going faster than 60mph, but I got to thinking. We hear that the CJ-3B was only "designed" to do 45-60 max, so what is the weak point in the drive train? Is it the rpm's for the 134 at 60mph? The axles? The tranny? The transfer case? Bearings?

Karl: Chuck Yeager! It's not the drive train, it's the short wheelbase and high center of gravity! While it may be OK go 60 MPH for a very short distance, it is risky business to do that on an Interstate, even with free-wheeling hubs and overdrive. At least tape your last will and instructions onto the the dash, so that the Highway Patrol knows where to send your remains in case you roll over if you get a blowout or a bearing seizes! Your Jeep is a fine off road vehicle, but not a Corvette!

anon: Just remember the Suzuki Samurai has a shorter wheel base than the 3B. So I don't agree that it can't be taken at 60 mph. You can say that any car or truck shouldn't be taken at 60 mph, because of a wheel bearing freezing up a blowout of a tire. As long as you know your Jeep and pay attention when you drive I don't see a problem with highway travel. The roads today I have to believe are better than the roads of the 50's and 60's. It's unfortunate that some of us working class have to use the 3B to get to work; we don't have the money to have six or seven cars and trucks to use when the main car doesn't work or we want to just drive the Jeep.

Andy Stock: In 1959, most speed limits were about 55 MPH. There were no 70-75 MPH freeways, so engineers didn't make any considerations about going that fast in most vehicles, especially one designed as a work vehicle. If Willys wanted to build a Corvette killer, they would have used an Aero or the Kaiser-Darrin to do it (Good Luck!) Also, a 40-50 year-old automobile, even with low mileage, has a bunch of 40-50- year-old parts on it. The Hurricane engine hates high rpms, 2800 is about redline. By the way, the Suzuki Samurai was notorious for rolling over, and a lot of lawyers got a lot of money for it. There's a reason they don't make them anymore. Although, I must admit, there's also a reason for the Wrangler, and the above is probably it.

Bill: Back in the late 60s I had a 55 3B with a 327 chevy in it and a overdrive. I put over 60,000 miles on it driving it at 60 to 70 on the freeways and never had a problem. My brother also had the small Bronco at the same time and I felt my 3B handled just as good at freeway speeds as the Bronco and they were both close to the same size. I agree the 4 cyl wasn't meant to run a long time at high rpm but with the right gearing and overdrive I don't see a problem. I do have to say that several times I took mine up to around 90 and at about 75 it would get a littles squirrely. That was in my younger days when several of us used to race them. I probably wouldn't do that now.

Pete: The short wheel base is part of the equation but it's the narrow wheelbase and high center of gravity that are a big factor. I bet when you had the 327 cid and the overdrive you also had wide tires on it. Of course wide tires are going to increase the wheel base width. It doesn't take very much additional width to increase the stability considerably when you are starting with only about 4-5 feet.

I think the 70's CJ-5 had a wider base than the 3B and the earlier CJ-5. Of course the Wrangler went wider still and lower gravity for the very reason that the CJ-5 was touted as a rollover death trap. Why the CJ-5 and not the 3B with this rep? Well because the CJ-5 was way more popular in numbers.

You can do high speed if'n ya want. I'll stick with low and slow. One can usually find back roads, even to commute on, and those flasher things work great when traffic is coming up fast on ya. (Course I live in Wyoming so I have some benefit there.) I commute in mine cause it's so fun to drive.

J: I didnt see death wobble up there. How about braking? I have trouble with my CJ-3A at about 25 mph let alone if I was to go 60. At the moment I'm stock except for the engine. I've gone from one lane to the the next and back again when trying to stop. (Well almost; it was perty bad.)

Dave: re. Braking: A vehicle with properly operating brakes should not wander when under normal braking. Does it pull to one side? Perhaps you have contaminated brake linings -- oil, etc. -- or else you have a problem with one wheel, or one side with brakes not working properly and the braking is unbalanced, causing it to pull to one side into the next lane?

Glenn Houston: After spending 35 years as an insurance adjuster I would never drive a 3B or CJ-5 over 55-60 mph; I saw too many rolled into a ball, and paid out a lot of money for injury and death claims. They quit making CJ's because AMC was paying out a lot of money for claims and lawsuits. If you want to drive one of these 60+ mph I hope you don't live around where I might be driving.

On the freeway Dave: I have a 1954 CJ-3B that I plow a private road and boarding house with. It's been in the family for 42 years and I wouldn't sell it for anything. It's very sentimental to me! Anyway, just driving it at low speeds, 15 mph, and making any sudden steering changes makes the Jeep quite 'squirrelly.' I think the designers unknowingly designed a safety feature into it by having it run only up to 45. A blowout at 60 could be disastrous in a 3B.

Joe Blow: A blowout in a Ford Explorer proved dangerous, and the wheel base is a lot wider than a 3B. Also I don't know where there is a 70-75 mph posted speed limit. Not in the northeast; maybe out west. I also think it's a joke that some people think that just because someone wants to go 60 mph on the highway they assume we want to build the 3B to run 9's in the quarter mile. I know more people with junky cars or trucks that I would feel more scared to ride in, than to go 60 mph in a 3B, and just think, there are a lot more of those on the road than the 3B. I think most people on this board are pretty smart, they know the limitations of their Jeep. I hope you are not the same people that drive their Cadillac Escalade 75 mph in the snow zipping in and out of traffic and telling someone in a 3B not to go over 40 mph. Boy this is a fun topic!!!

Karl: Joe, 75 MPH is the posted speed limit on I-29 in North Dakota. You can let it all hang out in Montana! Up here in Manitoba it's 100 klicks, 110 klicks in Saskatchewan. We are better drivers in the west than you east coast guys. Ha ha! I still say if you have a need for speed, leave the Jeep at home and get a Corvette or Porsche. You read what the retired insurance adjuster told us further up on this page.

Andy Stock: 70 MPH is the limit on non-city freeways up here in Minnesota. Wisconsin is 65, the Dakotas are 75. The minimum is 40. A 3B with overdrive can go 60 MPH even with the 5.38 gear ratio. Is that safe? It's your call. If you have a factory 3B with no seat belts and no top, there is a certain amount of risk, whether at 40 MPH on a back county road, 55 on a highway, or 70 on the interstate. We all understand this. Whether you want to go 60 on the freeway or 55 on the highway, that's your choice based on your experience with your Jeep.

Again, the Universal Jeeps were not built as highway cruisers or commuters. They were built to be sturdy little workhorses. They do that job and they have done it well for almost 60 years.

Bucky: I have had the need for speed before, having raced dirt track for a couple of years. But this last summer I sold the car and bought my first 3B. My wife and I took it out on some dirt roads at 35-40 mph. While I drove she read a book and got a tan. It felt great not to be in a hurry to get somewhere. We really enjoyed the little 3B.

anon: Even with an overdrive, no matter what you do to the F-head engine it is impossible to get it to go 65 mph.

Bruce W: That could be taken as a challenge. I have no desire to make my 3B capable of 65 MPH for any reason except maybe one -- to prove it can be done. Nelybel has shown herself capable of 55 with a full load of camping and hunting gear, as well as a 1963 Wards tent trailer behind, uphill at over a mile of altitude. I see no reason why she won't run 65 with an overdrive and no load. At over a mile high.

Lawrence: I can turn the 65+. I do feel a bit safer since I replaced the tires though.

Rusty: I put 34-inch tires on my 3B and went 65 mph on my GPS with 5.38 gears; ain't impossible.

Dave: If you guys are turning 65 with 5.38's and no overdrive, that motor must be spinning at 4,000 RPM at those speeds... unless you are running really tall tires....

Speed Pete: One day (on my GPS) I showed 75 mph. That was with my original type 750X15NDTs. I have the original F134 and stock tranny with no overdrive and 5.38's inthe axles. Yes the engine was high RPM but it didn't blow. When I blew past the sheriff it even took him a minute to flip on his lights. I started to slow down as he came up from behind and just as he thought I was going to pull over I made a hard right turn and went blasting on through the corn. Had a CJ-3B with a four wheel drive and a smokey on my tail. (Thanks for the lyrics C.W.)

Then I woke up and smelled my wife cookin' sausage.

Keith L.: I believe the issue is not about straight line speed. Given enough straight road and the right conditions (downhill and a tail wind) anything can bury the needle! The danger is when you have a head of steam and, say, a deer steps in front of you. This is when you suddenly learn about center of gravity and momentum; a quick left immediately followed by a quick, harder right will send the likes of any short wheelbase vehicle into cartwheels! This was the acid test that was performed on the CJ's which caused the re-design and introduction of the Wrangler.

anon2: Everyone's best bet is just to stay indoors and build a bomb shelter because maybe we will get hit by a weapon of mass destruction. Don't go to the store because maybe that bus you pass may hit a chuck hole blow a tire and hit your car and you hit three others. Better yet, don't go to work because with everyone else going to work at the same time there could be a chain reaction on the road. I get a laugh out of this topic. One person asks if it's possible to go 60 mph, NOT 80, NOT 100, in a 3B and all you people act like it is a terrorist act, yet I bet half of you people drive your SUV 80+ (even in the snow) and who cares you're in a 5000 lb. truck with 400 hp. Why don't you say something to people who put 327's, 350's, 302's in the 3B -- now I think that's nuts. Although it might be fun to pop wheelies every time you shift gears.

Karl: I hope all you 65 MPH+ Jeep drivin' lead foots have a guardian angel riding next to you in the passenger seat! Your right leg must shake like a rubber goose at such speeds in a CJ-3B! Well, some guys with the need for speed aren't happy until the telephone poles on the highway look like a picket fence! You still won't catch up to my Chevelle with a bored-up 350 small block on the Interstate. Wanna try? When I drive my Jeep, I like to muck in the mud and crash through the sloughs an willows in summer and through the snow drifts in winter.

anon2: My point is well made by Karl; it's OK to drive and act as crazy as you want if it's you, but no one else in the world has the right to go the legal speed limit, really only 60 if you can read. I guess Karl should read better; it's 60, 60mph, Sixty mph... not 75, not 70, 60!!

Andy Stock: Well, I wouldn't say half of us drive a 5000-lb SUV 80 MPH in the snow. I don't think four wheel drive does any good at that speed. The only vehicle I've ever driven 85 is my Econoline van, and only downhill.

Cars are built with a purpose. Pickups are built to haul stuff. Galaxies, Chevelles, Chargers, and the like are built to go fast and look cool. Minivans and SUVs are built to haul kids. Yugos are built to crush like a Coke can. I think we all know what a Universal Jeep (the real SPORT UTILITY vehicle) is built for.

Dave W.: Handling at road speed should be a vital priority. True story: I was on the interstate in my 2000 Silverado pickup on a rainy day. As I was changing lanes, I hit a piece of tractor retread laying in the road, all of a sudden my backend went out into a sudden spin which sent me into 360's, then off the road and slammed sideways into a tree. The front right fender ended up shoved all theway to the center of my hood, right front of cab caved in, yet I walked away with only some bruises due to the mass and safety features of the truck. The accident took a split second to happen, came out of nowhere. If the same thing happened to me doing the same speed in a 3B, would I be in the same condition? The vehicle probably would have flipped, rolled, or I could have been thrown or crushed on impact. The bottom line is, know your vehicle's limitations, and respect them. 65 or 70 may be fine for a 3B in ideal conditions, but come an emergency maneuver, etc., that's where the price may be paid indeed.

Interstate Chuck Yeager: I have been amused with the amount of discussion that the original question has raised. Thank you Anon2 for reminding everyone that the original question was about going around 60 MPH and not 65, 70 or 100 MPH!

I know full well the fact that one needs to respect the short wheelbase of a 3B. I have had scares in the CJ-7s I've owned. So those concerned about me, thank you, but I don't plan on doing myself in.

Chuck: Much of the literature written about our 3B's proclaims the little unit as being versatile enough for work OR pleasure. It is written that the 3B cancruise all day at 60 mph. The 3B was built for work, pleasure, or anything else Willys thought it would be useful for or capable of. I don't think anyone would expect to see a pink Surrey blasting down the freeway at 65+ mph with 3' of snow on the ground (stock, mind you). On the other hand, there are plenty of 8-cylinder Jeeps out there and the appropriate websites, magazines and such devoted to them.

The 3B, if maintained in good solid repair, is as safe as any other vehicle of its type and vintage. I use my M38A1 year round, but mostly to get through snow. In winter conditions, caution and correctly driving the vehicle probably makes it safer to use than the invincible Hummers and the like, who think their vehicle is above going slow or using caution. This is evidenced by those folks flying down the interstates in icy conditions. If folks actually WENT the speed limit, I would probably use the interstate in one of my old Jeeps but that isn't the case. Actual speeds for the beltway around D.C. average 80+ mph while it is posted 55.

I have seen many an old car traversing the valley here. They ALL use the parallel highway rather then the interstate. I am sure some huge Packard or Hudson from the early 50's could tool down the interstate with no problem in speed but they don't. It comes down to whether or not you intend to use the 3Bas a daily driver or pamper it as a funmobile. Most of us are not in the bind of use or lose, rather, we use the Jeep as a backup or weekend warrior. Most around here are used for hunting or plowing (ground or snow), that's about it. I use mine in winter to get around and in the summer cause they're so fun to drive. Every other Jeeper I've come across does the same. Strictly off-road, the majority sit waiting for better emissions, titles, tags, insurance etc. So, make it slow, make it fast, as long as she runs she'll be fun! By the way, any 3B should be able to attain and hold 55 mph and stop solidly from that speed. Anything less, then the ol' girl needs a check-up.

Mark Coleman: I've recently obtained a '63 CJ-3B. After reading "Mach 1 in a 3B" I'm a little concerned. I planned to use it as a going-to-camp vehicle (90 miles). Simple question: with the upgrades avalible (Saginaw steering, disc brakes, overdrive, lighting, etc.) will it function in a safe manner if driven properly? Also the speed wobble I've read so much about, if everything is rebuilt properly is it something that can still occur if a situation arises (certain bumps, etc.)? There are hundreds of miles of old logging roads in my hunting camp area and I was planning to use it to go exploring. I have rebuilt two CJ-5s and my current '85 CJ-7, so I have experience. I have always been drawn to the looks of a 3B.

Bruce W: Welcome to the world of CJ3B! The area I hunt and explore around in is about 70 miles away, about half of that on hi-speed, paved hiways. I've figured out how to get there with only about 1/2 mile of that madness. Now the trip is about 90 miles, takes about 3 hours to get there, and I love it! Slow down and take a look at what you're passing by. Getting there is half the fun! At the same time, I think that with an overdrive, and everything else in good shape, and if you don't wanta go "Mach One" in it, you'll be alright.

CJ-3B Dash Plate

Andy Stock: If you rebuild the running gear to top shape, make the upgrades you mentioned (if you don't have doors or a top, seat belts might be in order!) and use good, modern tires, two-lane 55 MPH highways would probably be OK. After all, the dash plate says the top safe speed is 60 MPH. The old logging roads shouldn't be a problem. That's one of the many things Jeeps were designed for.

Tom: Whatever you do, don't worry about the impatience of the people behind you. If you drive the posted semi speed (usually 55 MPH) and stay to the right, no one should have a real problem with that. And if they do? Too bad. Someday they will have a reason to drive slower than indy speeds and want you to have patience. I am in law enforcement and am well trained to drive at high speeds but I have a 3B with a 327 Chevy and my comfort level with it is 55 and under.

Thanks to all the contributors, and Roberto Flores for the cartoon. -- Derek Redmond

Photo Sources

For a more technical look at the speed question, see Almost Everything You Ever Wanted to Know About CJ-3B Speed, And Then Some by Ken "Oldtime" Bushdiecker.

See also the debate over whether To Upgrade or to Restore.

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Last updated 21 February 2005 by Derek Redmond redmond@cj3b.info
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