Cummins 4BT & Diesel Conversions Forums banner

1 - 20 of 66 Posts

·
Registered
Joined
·
176 Posts
Discussion Starter #1
Hello all,

I'm installing a 4BT in a 93' Suburban half ton 4WD.

The breakdown

using an 87' 4BT 105 horse.

Transmission is a 700R4 with a modified torque converter.

Oil pan was modified to clear the 4WD thrid member.

stock lift

Add input and enjoy.
 

Attachments

·
Registered
Joined
·
176 Posts
Discussion Starter #4
very interesting build. Have you got any details on the transmission, flexplate, converter and such?
The 700R4 bolted right up to the 4BT. The converter was modified by placing the mounting pads further out to match the TH400 bolt pattern on the flexplate. There were only three mounting pads on the converter which is all I need. That was the only major modification for the transmission assembly.

I'm comfortable about running a 700R4 with all the good parts available for them to be very strong.
 

·
Registered
Joined
·
127 Posts
I think you're goin to be my new best friend.. :)

What did you get the 4BT out of, or what adapter are you using, to allow it to bolt right up?

Where'd you get the motor, while we're at it?
 

·
Administrator
Joined
·
4,161 Posts
The 700R4 bolted right up to the 4BT. The converter was modified by placing the mounting pads further out to match the TH400 bolt pattern on the flexplate. There were only three mounting pads on the converter which is all I need. That was the only major modification for the transmission assembly.

I'm comfortable about running a 700R4 with all the good parts available for them to be very strong.
What was involved on balancing after you completed this?
 

·
Registered
Joined
·
127 Posts
also, what stall speed for the converter, how are you controlling lockup, and did you have anything special done to the governor, etc, in the transmission to address the diesel conversion, particularly with an eye to the 4BT's low-end torque output?

I'll be converting a 90 XJ and if that goes well a 89 S-10 Blazer as well. I'm going to be using a 700R$ and NP231C transfer case, with Dana44 axles. I've been leaning towards a 5.7 Olds diesel but would much prefer a 4BT if I can get some answers to some questions. I know what the Olds swap will entail, and it can be pulled off relatively cheaply. If the Cummins can be done for less than $4000 or so I'm all over it.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #8
What was involved on balancing after you completed this?
The converter was disassembled when the mounting pads were welded on. Once that was accomplished the converter was then assembled and balanced.

I'm looking into selling these converters (possibly) to other 4BT/700R4 enthusiests like me. :smile:
 

·
Registered
Joined
·
176 Posts
Discussion Starter #9
also, what stall speed for the converter, how are you controlling lockup, and did you have anything special done to the governor, etc, in the transmission to address the diesel conversion, particularly with an eye to the 4BT's low-end torque output?

I'll be converting a 90 XJ and if that goes well a 89 S-10 Blazer as well. I'm going to be using a 700R$ and NP231C transfer case, with Dana44 axles. I've been leaning towards a 5.7 Olds diesel but would much prefer a 4BT if I can get some answers to some questions. I know what the Olds swap will entail, and it can be pulled off relatively cheaply. If the Cummins can be done for less than $4000 or so I'm all over it.
Stall speed is 1200 RPMs. The lock-up is done by hydraulic means through a transmission modification. The governor is a typical diesel application unit used for a 6.2 diesel, so it should work just fine. The torque of a 6.2 diesel is around 240 ft-lbs. A 105 Horse 4BT puts out 280 ft-lbs. So that modest amount of more torque won't be a factor to a built 700R4 tranny.

700R4s can be built to handle 700 ft-lbs of torque. The one I had built handles 550 ft-lbs of torque which is plenty for what I'll be doing. So its up to you to decide on how much abuse you think your tranny will go through. One of the best things to do to keep your tranny together is keeping it cool. Run a good cooler to keep the tranny from heating up.

My swap has costed me $4500 so far. :eek:
 

·
Registered
Joined
·
1,203 Posts
Stall speed is 1200 RPMs. The lock-up is done by hydraulic means through a transmission modification. The governor is a typical diesel application unit used for a 6.2 diesel, so it should work just fine. The torque of a 6.2 diesel is around 240 ft-lbs. A 105 Horse 4BT puts out 280 ft-lbs. So that modest amount of more torque won't be a factor to a built 700R4 tranny.

700R4s can be built to handle 700 ft-lbs of torque. The one I had built handles 550 ft-lbs of torque which is plenty for what I'll be doing. So its up to you to decide on how much abuse you think your tranny will go through. One of the best things to do to keep your tranny together is keeping it cool. Run a good cooler to keep the tranny from heating up.

My swap has costed me $4500 so far. :eek:
any information on where you got your trans/converter? I am looking for a place willing to modify the converter like that, but haven't found a place to do it. I know i will need to replace the 700r4 that i have now, but i haven't made up my mind on that either. I don't plan on making huge power with the 4BT, but a little security would be nice.
 

·
Registered
Joined
·
120 Posts
I'm curious about what you did for an AC compressor? That is if you kept it of course.

I'm putting a 4bt in a 3/4 ton 93 Burb that had a 454 in it. I haven't looked into it too much yet but I think it has a special compressor since it's got front and rear AC. I also noticed that the belt for the 454 is a 6 groove and the 4bt uses an 8.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #13
any information on where you got your trans/converter? I am looking for a place willing to modify the converter like that, but haven't found a place to do it. I know i will need to replace the 700r4 that i have now, but i haven't made up my mind on that either. I don't plan on making huge power with the 4BT, but a little security would be nice.
I know some people who build converters and I got with them with my specifications to build one. What I had done to my converter is a carbon fiber clutch installed, stall speed lowered to diesel low end and heavy bearing. On top of these, the mounting pads located further out for TH400 converter bolt pattern. I'm looking into in buying a lot of these converters to sell for 4BT/700R4 combinations.

The transmission I bought through Ebay. It has all the goodies except harden input shaft and drum. It has Z-pack clutches, 5 pinion planetarys, valve body work, Sun Shell and hydraulic lock up for the converter. Its rated at 550 ft-lbs of torgue which is plenty for my stock 4BT

If you have questions just send a PM.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #14
I'm curious about what you did for an AC compressor? That is if you kept it of course.

I'm putting a 4bt in a 3/4 ton 93 Burb that had a 454 in it. I haven't looked into it too much yet but I think it has a special compressor since it's got front and rear AC. I also noticed that the belt for the 454 is a 6 groove and the 4bt uses an 8.
For the AC compressor, I used a dodge compressor. I purchased an AC bracket from cummins to mount the compressor higher up then stock dodge truck applications. The compressor is now located above the water inlet.

Originally, the GM compressor was to used but having a 7 groove pulley just as you mentioned I opted for the Dodge compressor. I think I might be able to use the Suburbans AC lines with little or no modifications to bolt to the Dodge Compressor...TBD.

Look in the pictures from the second post of this thread by clicking on the link to view the AC compressor location(second page).
 

·
Registered
Joined
·
8 Posts
newbie here

i'm thinking about a 4bt swap into a dually just dont know if its quite enough power for a heavy dually towing my chevelle... but if the mileage is good it cant tow any worse than a 350sbc right?? keep the great info coming!!!
 

·
Registered
Joined
·
8 Posts
how is the stock performance of the 4bt compared to the 350 tbi?? all the guys on the 4bt group on yahoo told me to run a 6bt in my dually but i think the 4bt turned up to 186hp & 466tq sounds better than stock 454 numbers 285hp & 400tq.... and 200hp & 485tq would not leave me wanting for power...
 

·
Registered
Joined
·
3,391 Posts
I had to read that 3 or 4 times to make sure I didn't miss something. The torque of a 6.2 L GM diesel is only 240 ft lbs?!! Is that for real?

Very nice swap and looks like it will be well worth all the hard work. You'll love the way it drives....
 

·
Premium Member
Joined
·
1,660 Posts
just looked for that pic of the AC compressor mount & counld find, for what its worth.. Curious to see how you did it!
 

·
Registered
Joined
·
176 Posts
Discussion Starter #19
I had to read that 3 or 4 times to make sure I didn't miss something. The torque of a 6.2 L GM diesel is only 240 ft lbs?!! Is that for real?

Very nice swap and looks like it will be well worth all the hard work. You'll love the way it drives....

Yep' the toruqe of the 6.2 is about 240 ft-lbs. The 6.2 had a displacement of 379 cu in. so the torque was okay.
 

·
Registered
Joined
·
176 Posts
Discussion Starter #20
just looked for that pic of the AC compressor mount & counld find, for what its worth.. Curious to see how you did it!

The pictures of the AC mount is in the photo album of Yahoo groups 4BT swap. I hadn't had a chance to upload pictures onto the photo album posted in this thread. But I'll Get R' done...

I figure if I do a 4BT or 6BT swap in any Gm truck for now on, I'm going to use "that" AC bracket because it clears the frame by re-loacting the compressor up above the water inlet. The alternator will have to flipped up of course.
 
1 - 20 of 66 Posts
Top