BJ60 3B and 5 spd into my BJ42

[freebie]

Thought I would share this project with you, since some of the problems are easy to deal with if you know about them ahead of time.

The 3B bolts in and connects up exactly the same of course, after I switched the 12 volt parts for 24 volt parts.
The 5 spd tranny requires some modification to the cross member (thanks Sea Potato) you take the cross member from the BJ60 and shorten it to match the BJ42 frame and will have to shorten the bottom of the passenger side frame mount. (this process requires cutting, grinding and drilling some new holes.
The rear drive shaft must be shortened 3.5" to fit and the front drive shaft must be 3.5" longer, I used the front end of the BJ42 drive shaft mated with the back end of the BJ60 drive shaft, (cut the t-case yoke off the bj42 drive shaft and weld the t-case yoke fron the BJ60 onto the BJ42 drive shaft) this ends up being the right lenght.
The holes in the floor for the shifters move back 3.5" and the shifters will need to be custom bent to fit? (I will be fabbing up a piece of steel plate to cover the whole area and fastening the shifter boots to that..
The power steering setup on the 84 BJ60 cuases a lot of problems in the 81 Bj42!! The easy fix is the upper rad hose, when I went to find a couple of hoses to piece together for this fix one of the hoses fits nicely by just cutting the ends shorter. ( I will get the part number up here later)
My 81 has a fresh water pump which fits the 84, but will not work due to the power steering pump location?
The fan clutch is larger and the fan is 1" in diameter larger, so the fan shroud needs to be trimmed, (I cut mine more then needed but it will make belt replacement etc easier)
The coolant reservoir moved forward a few inches to miss the power steering pump.
The strange one was the alternator, I removed the 12 volt alternator from the motor and installed the 24 volt to find the belt is not long enough, (the belt off the BJ60 is the same as the BJ42 so I guess the BJ60 alternator has a smaller pulley??)
So far thats all I can think of, the motors running, the drive shafts go in this weekend and the power steering will happen once I find a used box from a ????? at the wreckers.
I'll post some more info and pictures over the next week.

Cheers

[freebie]

I will add some pics of the final install later and list any part numbers I used.

[mel lowe]

Nice work!


That is a sweet set up you are building.



Keep the pics coming....

[freebie]

Thanks Mel

Here's a shot of the upper rad hose installed (Dayco Part #71039) had to trim about 4 inches off the engine end and 1 or 2 inches off the other, fits like a glove.

[freebie]

An update and a question??

So I went for another test drive tonight, mainly to see if new tires got rid of a shake. But also to see how the rpm, speed and EGT looked.
At 110Km its not pretty, but I quess if the ride was real smooth I would not be in a cruiser! my question is at 110Km on a slight incline the rpm was at 2450 but the EGT went over 950F just holding 110, not trying to accelerate. As soon as I was going down a slight incline the temp dropped of course. I think the exhaust system has too much backpressure as the truck seems a little underpowered and seems to heat up on the exhaust side very quickly even under slower less load conditions.
If anyone has had the same problem let me know. Or if anyone can tell me a reasonable backpressure for a N/A 3B let me know.

Cheers

[crushers]

most people that install a pyro into a NA 3B are shocked to see the temps that they have been running at for decades (hence the cracked precups everyone finds when pulling the head).

if you are running 2 1/2" then you have adaquate dimensioning for the exhaust, stock is 1 7/8"

950F is nothing at all, when you hit about 1200F then you have to start backing off a bit.

the NA 3B is not rocket, it is built for torque. i am curious as to what you expected?

110 with a NA 3B in a steel brick, 5th gear, 4.11 diffs, 92-98 hp (depending on a rotory pump or inline) WHEN NEW is about all you can expect. did you hear differently?

[freebie]

I wasn't expecting anything! I was just wondering if replacing the poorly installed exhaust system would have any effect on the egt's? and would you happen to know what an acceptable range of back pressure should be for this engine?

[lshobie]

Don't worry about backpressure - that is a gas engine thing.

[crushers]

if the exhaust has a serious kink in it then yes, the flow of exhaust gasses might be affected and the EGTs could go up... but it will take a good kink to do that.

as i mentioned, 950 F is well below acceptable limits... even a slight incline will generate more EGTs...

[seapotato]

Looks good ! glad that crossmember thing worked out ok...

as for egts, I just stuck one of those little digital pyros on my NA 3b powered bj70, and I was actually surprized at how LOW my egt's were ! I had to try pretty hard to get it into the 800's.

the probe is down the exhaust pipe about 6 inches from the manifold, as that was the only place I could get a drill in so it probably reads a smidge low.

Anyways, if your temps are only 3 digit, don't sweat it.

cheers,
ryan

[freebie]

Thanks Ryan

Yup the crossmember trick worked like a charm, what size exhaust and how much pipe, bends etc do you have??

If I get down that way in the next few weeks I'll stop by.

Cheers

[seapotato]

It's just the stock system, so whatever that is, nothing special. I went with bigger exhaust on my other truck, and it made quite a difference to the egt's.

Seemed to go a little better on the highway too, and that's before I added all the fancy shit so it really went...

The BJ70 I'm pretty much leaving alone, gets me around, and gets decent mileage, I just wanted the pyro to make sure I wasn't cooking anything on hills, you never know till you put one in.

course, having said that, it's misbehaving a touch at the moment, if I turn on the headlights, the truck turns off.... must be a pinched wire or something from when I changed the fenders...

If you're going to redo the exhaust, definately go up a size or two, never seems to hurt.

cheers,
ryan