BJ4* 3B highway performance (1 Viewer)

[amaurer]

My 3B is far from stateside at this point, so I pass my time reading this forum. I've read lots of woe about NA 3B's climbing hills on the highway, as well as some scary EGT readings in similar situations from people who bothed to measure a NA 3B.

So whats the scoop?

What IS a realistic highway speed for a 3B 40?

With a bone stock truck do I need to worry about burning things up just from climbing a long highway hill? Will I have to floor it to keep speed?

I can't figure out if the posters with problems maintaining speed/high EGT have other driveline mods that may contribute...

 

[bj70_guy]

3Bs are just fine on the highway. My 70 will maintain 120 km/h with no problem - until the road heads uphill. It's pretty mountainous terrain here, so a long trip will inevitably go over some steep grades. I just keep the engine in the powerband, and try not to look at how slow you're going! Lots of grades mean 3rd gear and 65km/h. Get used to going straight to the far right lane when things head uphill.

I dealt with EGTs by never installing a pyro
My truck has 362,000km/s on it and has had no engine trouble to speak of.

 

[roscoFJ73]

I can't figure out if the posters with problems maintaining speed/high EGT have other driveline mods that may contribute...

Their engines are most probably perfectly healthy.

The fact is ,the 3B/4sp means the BJ40 was never meant to be a highway cruiser for North America.
Its more at home bumping along some dusty track in east Africa or outer Mongolia.

Think of it as a high speed tractor rather than a low speed car

IMO if you are going to own one of these,then you should have a another vehicle that can do the highway speed when needed.

 

[cruiser_guy]

A BJ40 will be worse off on the highway than a BJ60 as the BJ40/42 has a 4:11 differential gearing and the '60 has 3.7 gearing. To get to 120kph you'd have to be running 31's or 33's, stock tires will be into the upper end of the power band at 100/110kph. Is your truck a 4 speed or a 5 speed (Norm's truck is a 5 speed and BJ40's are all 4 speed/'42's after '83 have 5 speeds)?

I recommend a pyrometer as I have cracked a pre-cup going through the Siskyou's (northern California/southern Oregon) in about 2000 or so.

 

[crushers]

IMO if you are going to own one of these,then you should have a another vehicle that can do the highway speed when needed.

agreed...

the 3B is a tough old girl but can be S L O W especially on the hills... i do recommend installing a pyro (and a turbo)

 

[amaurer]

Mine is a 82, with the 4 speed.

I'm OK going slow, the vast majority of my usage is going to be commuting, which I'm lucky to exceed 35 on the highway (yay for the Bay Area).

But, if I do drive up into the mountains I want/need to know how much care is warranted. I guess what I'm asking is; will I *know* when I'm pushing it, or do people obliviously melt 3B's trying to drive up highway grades?

(I should be clear that "highway grades" can mean a lot of things, depending on what you consider typical. Primarily I'm concerned with the sort of thing you'd encounter on major east-west routes, and am less concerned about the kind of roads you might find climbing up to somewhere interesting. Case in point: If I tried to drive to Chicago to visit my family, should I budget travel time through the Western US at 35mph average? )

 

[roscoFJ73]

But, if I do drive up into the mountains I want/need to know how much care is warranted. I guess what I'm asking is; will I *know* when I'm pushing it, or do people obliviously melt 3B's trying to drive up highway grades?

Thats what the Pyro is for, you have to watch the exhaust gas temp and ease off the happy pedal when it goes up
It doesnt come out and smack you in the head,you have to watch it

 

[wesintl]

Mine is a 82, with the 4 speed.

I'm OK going slow, the vast majority of my usage is going to be commuting, which I'm lucky to exceed 35 on the highway (yay for the Bay Area).

Yeah talk to us a year or two later.

But, if I do drive up into the mountains I want/need to know how much care is warranted. I guess what I'm asking is; will I *know* when I'm pushing it, or do people obliviously melt 3B's trying to drive up highway grades?

only way to really know is to have a pyro on it. until then you could burn 1200 or 2000*, you won't know you're going to kill it until it starts to overheat. [/QUOTE]

(I should be clear that "highway grades" can mean a lot of things, depending on what you consider typical. Primarily I'm concerned with the sort of thing you'd encounter on major east-west routes, and am less concerned about the kind of roads you might find climbing up to somewhere interesting. Case in point: If I tried to drive to Chicago to visit my family, should I budget travel time through the Western US at 35mph average? )

I can't tell you about cali or nevada but from utah to nebraska you will hate life in a NA 3b (at least until the fun wears off)

 

[eleblanc]

I can run steady at 110 kmh that is with 33.5" tires, H55 5 speed and 4.88. But hills are a pain. Turbo is the next upgrade on my truck

 

[Diescipel]

I have climbed from the floor of Death Valley to about 8000' in one day with no problem, but it was slow. I do not have a pyro but you will notice that your coolant temp will rise if you lug the engine with a heavy throttle. I spent a lot of time in 3rd gear, but I all was kosher. My '83 42 with it's 5 spd. and 33s will cruise all day long at 65 mph if I want, but yes, hit a hill, and it slows way down.

By the way, my BJ is my fav car for trips into SF. So manoueverable (sp?), so much torque for the hills, so ugly that nobody f--s with you.

B

 

[amaurer]

By the way, my BJ is my fav car for trips into SF. So manoueverable (sp?), so much torque for the hills, so ugly that nobody f--s with you.

Funny you should say that as thats something I'm explicitly looking forward to. My only car right now is an '04 Ram... absolute f*in nightmare in SF.

 

[cruiser_guy]

When I blew the pre-cup in the Siskyou's (driving up I-5, nothing special) I did not realize that I was doing any damage until the rattle started and then I didn't know what the problem was until the engine quit.

The actual pre-cup was not discovered until the engine was torn down.

All my diesels will have pyrometers from now on.

 

[Green Lantern]

FWIW....
I drove my 81 BJ42 with 4 speed from Vancouver to Fort Worth without a pyrometer. I adjusted my speed and gear setting solely by the sound of the motor. The only time I overheated the motor was climbing the first long grade in Washington. I pulled over and idled the motor. It cooled down in about two minutes. After that, I drove up steep grades in 3rd gear with the flashers on.

It was slow, but folks were courteous as they passed me and I made it home with no engine problems. I put a pyrometer on the motor last year and now I drive according to the EGT. The pyrometer gives me immediate info on the load my motor is pulling. Slowing down and/or changing gears gives fast relief to the motor and I'm a better driver for it.

HTH
Happy Trails! N

 

[brownbear]

A pyro really is a cheap way to ensure you don't over do it.

But you could just run the fuel setting lower and bag on it all day if you want with out over doing the EGT's.

If you want the most from the engine, get a pyro. Mr Yoda sets these trucks up for the middle of the road guy. At sea level it could use more fuel. At high altitudes it needs to be a little less. If you have a pyro you can make changes for where you live.

But yah, most of them ran hot/hard for 20 years plus with no damage. Now that you know better and want to keep it healthy for many more.....

do as you please.

 

[Mike Shull]

Wouldn't you want a turbo first before you try measuring the temp of it?
Really though....if you blow the internals out of a turbo on a Toyota does it really stall out the engine? I have blown one turbo on a semi that had no piro and it wanted to run.....and smoke...never saw so much smoke....I had to stall out the truck in gear....never again.

 

[cruiser_guy]

Wouldn't you want a turbo first before you try measuring the temp of it?
Really though....if you blow the internals out of a turbo on a Toyota does it really stall out the engine? I have blown one turbo on a semi that had no piro and it wanted to run.....and smoke...never saw so much smoke....I had to stall out the truck in gear....never again.

When you blow out the turbo seals you're giving the engine a source of oil to burn!! It will keep running because it has a source of fuel that you can't shut off.

The pyrometer is useful even without a turbo as you could still easily overheat the pistons which is what you're trying to avoid. The pyrometer is NOT to protect the turbo, it's there to protect the engine which is why mine is mounted as close to the cylinders as possible, in other words BEFORE the turbo.

 

[cruiser user]

Get a pyro

I bought my bj 42 in Connecticut and drove it home on the interstate at 70-75 mph, it seemed fine. Drove it around for a couple of months just as fast as it would go. Then I installed a pyro and found I was getting 1400-1500 degree temps at highway speeds and up the slightest hills !!!! Turned down the juice and took my foot off the pedal and man was it really slow! Finally I put a new 2-1/2 inch exhaust with a flowmaster on it and now I can cruise at 55-65 with it at 1100 degrees... Also watching the pyro keeps me from cooking it on the long steep hills around here. I feel it was the best investment in prolonging the life of the engine I have made so far. Tim

 

[dblugly]

I have been watching this thread and I have a question, does anyone make a 24 volt pyro? I know it works off of temp, but what about Gage lighting, Etc..

USER, is your exhaust from the header back, or the whole system?

 

[Tapage]

I have been watching this thread and I have a question, does anyone make a 24 volt pyro? I know it works off of temp, but what about Gage lighting, Etc..

I thought it's pretty cheap insurance get a better exhaust .. like 2.5" and then a Pyro before a turbo .. sure turbo reasonable step but much times the $$$ become a factor over dreams ..

Anycase at your question, I'm not sure if you can get a 24V Pyro

Nice place to start searching ..

http://www.egauges.com/eg_typeI.asp...l&Letter=All&Needle=All&Diameter=All&Manf=All

I love those ..

http://www.dieselmanor.com/isspro/EV_black-black-red.asp

 

[cruiser_guy]

I have been watching this thread and I have a question, does anyone make a 24 volt pyro? I know it works off of temp, but what about Gage lighting, Etc..

USER, is your exhaust from the header back, or the whole system?

I'm 99% positive that Isspro has a 24v model.