Mach 1 in a 3B?



How fast is it safe to drive in a 50-year-old CJ-3B, and what is the limitingfactor? This was the thread started in late 2004 on The 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.

Chuck Yeager: I had a to drive to another community about 25 miles away thismorning. 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. Verysmooth and stable!!

There have been discussions here in the past about the speed limit for a 3B. Thecomment 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 hearthat the CJ-3B was only "designed" to do 45-60 max, so what is the weak point inthe 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 highcenter of gravity! While it may be OK go 60 MPH for a very short distance, it isrisky business to do that on an Interstate, even with free-wheeling hubs andoverdrive. At least tape your last will and instructions onto the the dash, sothat the Highway Patrol knows where to send your remains in case you roll overif 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. SoI don't agree that it can't be taken at 60 mph. You can say that any car ortruck shouldn't be taken at 60 mph, because of a wheel bearing freezing up ablowout of a tire. As long as you know your Jeep and pay attention when youdrive I don't see a problem with highway travel. The roads today I have tobelieve are better than the roads of the 50's and 60's. It's unfortunate thatsome of us working class have to use the 3B to get to work; we don't have themoney to have six or seven cars and trucks to use when the main car doesn't workor we want to just drive the Jeep.

Andy Stock: In 1959, most speed limits were about 55 MPH. There were no 70-75MPH freeways, so engineers didn't make any considerations about going that fastin most vehicles, especially one designed as a work vehicle. If Willys wanted tobuild a Corvette killer, they would have used an Aero or the Kaiser-Darrin to doit (Good Luck!) Also, a 40-50 year-old automobile, even with low mileage, has abunch of 40-50- year-old parts on it. The Hurricane engine hates high rpms, 2800is 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 makethem 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 neverhad a problem. My brother also had the small Bronco at the same time and I feltmy 3B handled just as good at freeway speeds as the Bronco and they were bothclose to the same size. I agree the 4 cyl wasn't meant to run a long time athigh rpm but with the right gearing and overdrive I don't see a problem. I dohave to say that several times I took mine up to around 90 and at about 75 itwould get a littles squirrly. That was in my younger days when several of usused 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 wheelbaseand high center of gravity that are a big factor. I bet when you had the 327 cidand the overdrive you also had wide tires on it. Of course wide tires are goingto increase the wheel base width. It doesn't take very much additional width toincrease the stability considerably when you are starting with only about 4-5feet.

I think the 70's CJ-5 had a wider base than the 3B and the earlier CJ5. Ofcourse the Wrangler went wider still and lower gravity for the very reason thatthe CJ-5 was touted as a rollover death trap. Why the CJ-5 and not the 3B withthis 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 canusually find back roads, even to commute on, and those flasher things work greatwhen traffic is coming up fast on ya. (Course I live in Wyoming so I have somebenefit 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 myCJ-3A at about 25 mph let alone if i was to go 60. At the moment I'm stock exeptfor the engine. ive gone from one lane to the the next and back again whentrying to stop. (Well almost; it was perty bad.)

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

Glenn Houston: After spending 35 years as an insurance adjuster I would neverdrive a 3B or CJ-5 over 55-60 mph; I saw too many rolled into a ball, and paidout a lot of money for injury and death claims. They quiit making CJ's becauseAMC was paying out a lot of money for claims and law suits. If you want todrive one of these 60+ mph I hope you don't live around where I might bedriving.

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'svery sentimental to me! Anyway, just driving it at low speeds, 15 mph, andmaking any sudden steering changes makes the Jeep quite 'squirrelly.' I thinkthe designers unknowingly designed a safety feature into it by having it runonly 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 isa lot wider than a 3B. Also I don't know where there is a 70-75 mph postedspeed limit. Not in the northeast; maybe out west. I also think it's a joke thatsome people think that just because someone wants to go 60 mph on the highwaythey assume we want to build the 3B to run 9's in the quarter mile. I know morepeople with junky cars or trucks that I would feel more scared to ride in, thanto go 60 mph in a 3B, and just think, there are a lot more of those on the roadthan the 3B. I think most people on this board are pretty smart, they know thelimitations of their jeep. I hope you are not the same people that drive theirCadillac Escalade 75 mph in the snow zipping in and out of traffic and tellingsomeone 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 letit all hang out in Montana! Up here in Manitoba it's 100 klicks, 110 klicks inSaskatchewan. 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 aCorvette or Porsche. You read what the retired insurance adjuster told usfurther 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 cango 60 MPH even with the 5.38 gear ratio. Is that safe? It's your call. If youhave a factory 3B with no seatbelts and no top, there is a certain amount ofrisk, whether at 40 MPH on a back county road, 55 on a highway, or 70 on theinterstate. We all understand this. Whether you want to go 60 on the freeway or55 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. Theywere built to be sturdy little workhorses. They do that job and they have doneit well for almost 60 years.

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

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

Bruce W: That could be taken as a challenge. I have no desire to make my 3Bcapable 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 huntinggear, as well as a 1963 Wards tent trailer behind, uphill at over a mile ofaltitude. I see no reason why she won't run 65 with an overdrive and no load. Atover a mile high.

Lawrence: I can turn the 65+. I do feel a bit safer since I replaced the tiresthough (see https://cj3b.info/Tech/Tires.html).

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 mustbe spinning at 4,000 RPM at those speeds... unless you are running really talltires....

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 thesheriff it even took him a minute to flip on his lights. I started to slow downas he came up from behind and just as he thought I was going to pull over I madea hard right turn and went blasting on through the corn. Had a CJ-3B with a fourwheel 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 enoughstraight road and the right conditions (downhill and a tail wind) anything canbury the needle! The danger is when you have a head of steam and, say, a deersteps in front of you. This is when you suddenly learn about center of gravityand momentum; a quick left immediately followed by a quick, harder right willsend the likes of any short wheelbase vehicle into cartwheels! This was theacid test that was performed on the CJ's which caused the re-design andintroduction of the Wrangler.

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

Karl: I hope all you 65 MPH+ Jeep drivin' leadfoots have a guardian angel ridingnext to you in the passenger seat! Your right leg must shake like a rubber gooseat such speeds in a CJ-3B! Well, some guys with the need for speed aren't happyuntil the telephone poles on the highway look like a picket fence! You stillwon'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 thesloughs an willows in summer and through the snowdrifts in winter.

anon2: My point is well made by Karl; it's OK to drive and act as crazy as youwant if it's you, but no one else in the world has the right to go the legalspeed 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 thesnow. I don't think four wheel drive does any good at that speed. The onlyvehicle 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. Minivansand SUVs are built to haul kids. Yugos are built to crush like a Coke can. Ithink we all know what a Universal Jeep (the real SPORT UTILITY vehicle) isbuilt for.

Dave W.: Handling at road speed should be a vital priority. True story: I was onthe interstate in my 2000 Silverado pickup on a rainy day. As I was changinglanes, I hit a piece of tractor retread laying in the road, all of a sudden mybackend went out into a sudden spin which sent me into 360's, then off the roadand 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 awaywith only some bruises due to the mass and safety features of the truck. Theaccident took a split second to happen, came out of nowhere. If the same thinghappened 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 orcrushed on impact. The bottom line is, know your vehicle's limitations, andrespect them. 65 or 70 may be fine for a 3B in ideal conditions, but come anemergency maneuver, etc., that's where the price may be paid indeed.

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

I know full well the fact that one needs to respect the short wheel base of a3B. 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 unitas 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 elseWillys thought it would be useful for or capable of. I don't think anyone wouldexpect to see a pink Surrey blasting down the freeway at 65+ mph with 3' of snowon the ground (stock, mind you). On the other hand, there are plenty of8-cylinder Jeeps out there and the appropriate websites, magazines and suchdevoted to them.

The 3B, if maintained in good solid repair, is as safe as any other vehicle ofits 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 makesit safer to use then the invincible Hummers and the like, who think theirvehicle is above going slow or using caution. This is evidenced by those folksflying down the interstates in icy conditions. If folks actually WENT the speedlimit, I would probably use the interstate in one of my old Jeeps but that isn'tthe case. Actual speeds for the beltway around D.C. average 80+ mph while it isposted 55.

I have seen many an old car traversing the valley here. They ALL use theparallel highway rather then the interstate. I am sure some huge Packard orHudson from the early 50's could tool down the interstate with no problem inspeed 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 ofuse or lose, rather, we use the Jeep as a backup or weekend warrior. Most aroundhere are used for hunting or plowing (ground or snow), that's about it. I usemine 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, themajority sit waiting for better emissions, titles, tags, insurance etc. So, makeit slow, make it fast, as long as she runs she'll be fun! By the way, any 3Bshould 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 (90miles). Simple question: with the upgrades avalible (Saginaw steering, discbrakes, overdrive, lighting, etc.) will it function in a safe manner if drivenproperly? Also the speed wobble I've read so much about, if everything isrebuilt 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 myhunting camp area and I was planning to use it to go exploring. I have rebuilttwo CJ-5s and my current 85 CJ-7, so I have experience. I have always been drawnto the looks of a 3B.

Bruce W: Welcome to the world of CJ3B! The area I hunt and explore around in isabout 70 miles away, about half of that on hi-speed, paved hiways. I've figuredout how to get there with only about 1/2 mile of that madness. Now the trip isabout 90 miles, takes about 3 hours to get there, and I love it! Slow down andtake a look at what you're passing by. Getting there is half the fun! At thesame 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.

Andy Stock: If you rebuild the running gear to top shape, make the upgrades youmentioned (if you don't have doors or a top, seat belts might be in order!), anduse good, modern tires, 2-lane 55-MPH highways would probably be OK. After all,the dash plate says the top safe speed is 60 MPH. The old logging roadsshouldn'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, noone should have a real problem with that. And if they do? Too bad. Someday theywill have a reason to drive slower than indy speeds and want you to havepatience. I am in law enforcement and am well trained to drive at high speedsbut 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

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

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