1984 110SW Cummins 6BT/NV4500/LT230

Well, this has been going on for a decade, finally to a point where I can start wrapping it up and posting some pics. When it started, there were only a handful of us doing the 6BT - Nick over in the UK. Oilburner in his 109 in Canada. A couple others. So it was a bit of a walk in the dark. Now, well....there are many....and I'd probably go with the R2.8. But the 6BT12V with a P7100 pump is something special.

It doesn't look like I can imbed pics sequentially, so I'll do this as a starter post and reply with the steps.

Started as a 200tdi. After being passed by semi's on East I80 grade in the sierras - this going to be one of its haunts - the need for more torque was mandated. I'm prone to overkill, so the 4bt just wouldn't do. I got a nice deal and choice on a 1997 6BT out of a Binks Armored car fleet being broken locally. The size of the 6bt compared to the 200tdi is remarkable.

It seemed advisable to reinforce the frame as others had experienced some cracking after conversation. This created a start and a stop and a re-start on a 'new' used ex-mod frame as my original frame was found to be just too far gone when I got into reinforcing. I plated top and bottom with 3/16" through out. 1/8" to 3/6" on one side also. So "C" boxed the frame. Also reinforced the spring brackets - it was going to get heavier.

This conversion also requires changing to the p38 steering box and mounting it outside the frame. So at this time, I built the box mount and panhard rod brackett directly to the frame. Then off to galvanizing

I snaked a 'new' 2002 300TDI harness through the frame while I could stand it on end. Then began fitting it to the frame.
I had obviously done a 'build up' to locate the motor relative to bulkhead and cut the bulkhead for the bigger bellhousing and starter interferences.
Location. Location. Location. It a game of 1/16 inches. The motor is tight between the forward cross member (and radiator group) and the bulkhead. Not just at the engine head, but the further back you go, the more you have to open up the hole in bulkhead. the brake drum is also up into the battery box support (which got modified too). Height is a fight too. The intake plenum and the hood are at war - even with a Puma hood. Underneath, after fitting the reversed oil pan, there is still a fight for travel. Left and right is the tightest game - the front drive shaft wants to hit the bellhousing (I ground off one bolt) and the brake drum wants to hit the left frame rail. On the other side, you're loosing space at the gas pedal.

In the end, I wish I were about 1" further back. It's too tight for me to get a normal socket on the harmonic balancer bolt to bar the motor over. I can get it on the alternator though and the belt has enough grab to bar the motor over that way.

a few more fixturing pics

Some of the subtleties: I built an adapter for the NV4500 to LT230 connection(existing kits where too long). I used the Dodge 31tooth NV4500 main shaft and had a new spline (24/48 - 32tooth) ground onto it. The original spline is to big to fit into the lt230 input gear. Got a few new 1:1 input gears from Ashcroft (and a few other t-case goodies) and had the female spline EDM cut into that. I have CAD drawings and files of all of these if anyone is interested.

Clutch - Using the OEM defender master to an OEM dodge slave. Used a -04 Swage to -04 JIC adapter on the line running from the master. A -04 JIC flex line. And a -04 JIC to 'whatever the heck it is' fitting adapter in the slave (Jegs and Summit sell them). Works great. I put an up-rated clutch in it and its still not a beast to clutch.

Griffith radiator. Bought an inner cooler core that fit the area and welded up the end boxes. I plan on putting in AC (the compressor is on the motor), so I mounted a discovery condensor and twin pusher fan pack on the nose (using the desert extended nose). On relay at 180F for now and seems to be working well. Comes on and holds temp when idling and warming up, but shuts off as soon as I'm driving and getting air flow.

Fuel lines: Changed the pick up to the top of the tank to use larger lines. Ran stainless swage all the way and a big return. The stock lift pump is good to about 400hp flow, so I'm not adding an electric boost pump for now.

Various location pics here. While I say I wish it were an inch back, you can see the issue at the battery box with the shifter. So maybe not.

LT230 shift linkage is a bit Rube Goldberg, but it works quite well.

Custom tunnel layup in fiberglass using foam as a buck. Later used the foam as underside insulation as well. I'm good with layups. But I hate it with a passion. Rubber boots from various sources worked out. Had to bend the shifter output shaft a little to get it in the right place.

I did a custom SS exhaust I'll get some pics of up here shortly.

Oh - Power steering. Always fun. A game of 'name that fitting to 'what the hell is this?'. But got it sorted with several try's and mostly through Jegs and Summit. Was fighting a heavy wheel - until I tested the pressure. Dead pump. New pump. Pinky steering!. Awesome!
Steering rod has to be lengthened several inches due to the outboard fitting of the P38 box. And a custom mount for the steering damper of course.

OEM Vacuum pump to a vacuum reservoir (Jegs) for brake boost.

I just did the 3000rpm rev limiter increase and some fueling tweaks, so looking forward to seeing how it runs. It was awesome already, but very short in RPM: 800 to 2400 (really 2000).
Cant upload the movie of first run unfortunately

wow looks great ! upload the video to YT and just post the link here. how did you calculate the new suspension coils?

Napalm00 said:

wow looks great ! upload the video to YT and just post the link here. how did you calculate the new suspension coils?

Click to expand...

I used RTE’s 3” RRC springs. Talking to them, we were confident it would settle to 2” lift. It’s pretty much spot on. Terrafirma +2” rears.

using OME +2” shocks. Rides very well.

Wow..that....that is a LOT of work. Great engine of course...but wow. Can't wait to see the final product!

Holy cow, the engine is so big. I’ve seen some of the 130s in the UK with the 6BT, but never appreciated just how much shoehorning was involved.

And you built a chassis around your chassis!

Awesome seeing these progress pics after all this time! So much good work on this truck, and it’s all so well thought out. Keep up the good work Tony, it will be worth the wait.

I’m less concerned with positioning the R2.8. Much less. Damn.

Holy incredible smokes!!!

I am impressed, especially with your tenacity to make it through the project and come out the other side with a successful outcome. I’ve seen Nick’s conversions on YouTube and it’s so capable.

FWIW, your shifter arrangement is very similar to the Puma side by side layout.