Builds Stevo's 6BT60 Build Thread

[StevoJonesFJ60]

Earlier tonight I had my old 2F seize up on me while I was driving. Unfortunately this forces me to go ahead with my planned diesel swap way ahead of schedule. I had wanted to run my current setup for more time, at least for the summer but sometimes things happen that you just can't control.

Fortunately for me though I have a perfect donor truck ready to give up its heart for transplant into my FJ60. My goal will be a combination of my favorite truck with my favorite motor. A FJ60 with a 5.9L Cummins 6BT engine.
I have to thank all of those on this site who have enabled me to get this far, and I plan on documenting this build so it can be used as a reference in the future.

I will be using these two trucks to create the finished product. All of the information on the FJ60 build can be found here -- https://forum.ih8mud.com/60-series-...al-build-thread-fj60-fj62-fj80-axle-fj68.html

 

[boots4]

Bitter sweet I bet with all the work you've done to the 2f lately but great to see the diesel swap moving forward.

 

[StevoJonesFJ60]

Bitter sweet I bet with all the work you've done to the 2f lately but great to see the diesel swap moving forward.

Yeah, it was pretty disappointing. But I took it out for one last ride on the trails out back before it went so at least that was fun. I wanted to have a truck for the summertime but I doubt this will be finished before then.

Fortunately swapping in 6BT should be pretty similar to a 4BT just longer. So I'll probably be looking for advice from you in regards to mounts and whatnot.

First thing I need to do ais rip out the old and start getting all of the new ready to go in. Its too bad the Toyota drivetrain won't be able to hold up for what I have in mind powerwise. So I'll be needing to swap in some running gear to handle to torque from the 6BT.

As of right now that going to consist of:
D60 from the front of the Dodge, needs to be regeared
14 Bolt I picked up with 4.10 gears
Eaton 5-speed overdrive manual transmission
Divorced NP205

 

[klinetime574]

Tuned in.

Hope this swap goes easy for ya

 

[Combat Chuck]

Subscribed.
I look forward to this build.

 

[GLTHFJ60]

 

[StevoJonesFJ60]

Now for a little bit of background on the 5.9. I got a screaming deal on a first generation 1992 Dodge D250. It was $1300 delivered to the shop where I had my 60. It was in running and driving condition but the body is in very rough shape.

In terms of power I am not planning on going crazy. The final goal is somewhere around 300 horses at the rear wheels and 600-700 ft-lbs.
I have already upgraded the compressor on the turbo to a 60mm wheel and housing and have installed a 3200 rpm spring as well as a new fuel pin.

As I prep this motor to go in I plan on doing a few things as preventative steps, namely gaskets and seals on the pump, the valve covers, and killer dowel pin, and also replacing the freeze plugs with aftermarket ones.

I have a lead on an Eaton-fuller 5-speed transmission which I will see about tomorrow. I hope I can trade an Eaton 8LL I have sitting around to cover some of that cost. Then I just need to get a divorced NP205 and I should be ready to start swapping things into the truck.

 

[davegonz]

Why not go with the NV4500 that came in those Dodge trucks? A buddy of mine has an 80 with a 6BT and that tranny is sweet.

Good luck with the build.

 

[StevoJonesFJ60]

Why not go with the NV4500 that came in those Dodge trucks? A buddy of mine has an 80 with a 6BT and that tranny is sweet.

Good luck with the build.

I have been looking for a NV4500 for quite some time and unfortunately there aren't any in my area. It also seems like everyone wants $2000 for one of them nowadays.

If I came across one I would totally jump on it because it would simplify the build, but because nothing has shown up I'm going to take the current route. The ratios are pretty close between the two transmissions so either one should work pretty well.

 

[Tapage]

I dunno anything about eaton manual .. but know NV4500 are awesome .. but as awesome are expensive. But for 2K you could get a new NV4500 ..

Which are the ratios on the Eaton .?

Nice build .. tire size are you planning .?

 

[StevoJonesFJ60]

I dunno anything about eaton manual .. but know NV4500 are awesome .. but as awesome are expensive. But for 2K you could get a new NV4500 ..

Which are the ratios on the Eaton .?

Nice build .. tire size are you planning .?

Ratios on the eaton are I think around 7:1 for first gear, with an overdrive of around 23 to 25%

I'm going to be running 4.10 gears in the axles with a tire size probably around 39-40"

That should put me right in the sweet spot for cruising on the highway.

 

[GLTHFJ60]

Ratios on the eaton are I think around 7:1 for first gear, with an overdrive of around 23 to 25%

I'm going to be running 4.10 gears in the axles with a tire size probably around 39-40"

That should put me right in the sweet spot for cruising on the highway.

Except for the fact that you plan to drive 39-40" tires on the highway. Don't you think you'll get some serious issues tracking, and with balance, when running tires that large on the highway for any amount of time?

 

[StevoJonesFJ60]

Except for the fact that you plan to drive 39-40" tires on the highway. Don't you think you'll get some serious issues tracking, and with balance, when running tires that large on the highway for any amount of time?

Yeah... Thinking about that maybe I'll limit my tire size a bit, but I know there are a couple of people running some big tires on their DD. I'm not planning on tons of highway time, but then again maybe I'll just run the 35" tires I have.
For tracking I plan on installing hydraulic assist which should help stabilize the truck.

What issues are there with getting larger tires balanced? There are a bunch of places by me that specialize in OTR trucks they have the equipment to balance larger tires I believe.

 

[davegonz]

I'd keep it simple and run 35's with the 3.7x gears that should keep you in the sub 2000 RPM range at 65-70 mph range. But then again, those tires might look small since your truck is SOA.

 

[GLTHFJ60]

Yeah... Thinking about that maybe I'll limit my tire size a bit, but I know there are a couple of people running some big tires on their DD. I'm not planning on tons of highway time, but then again maybe I'll just run the 35" tires I have.
For tracking I plan on installing hydraulic assist which should help stabilize the truck.

What issues are there with getting larger tires balanced? There are a bunch of places by me that specialize in OTR trucks they have the equipment to balance larger tires I believe.

I'm thinking that the super large tires you're going to want are only going to come in bias ply, which is inherently more difficult to balance, but even if they were radials, unless you're planning on running a 20" rim with 39-40" meats, think of the amount of rubber that can change shape while driving down the road, both in terms of sway but also in roundness. I suspect that you'd need a pound of balancing weight to get it right.

Aside from balancing, monster tires like that don't come in narrow sizes, so expect to find 14"+ widths as part of the game. For Moonshine, I'm finding that the 13.5" wide tires have a serious amount of wander on regular roads around here in NC. Balance isn't too bad, even without weight, but my 37" pits measure out to 35" tall.

I'd keep it simple and run 35's with the 3.7x gears that should keep you in the sub 2000 RPM range at 65-70 mph range. But then again, those tires might look small since your truck is SOA.

His 35's already look small!

 

[TCinVA]

A buddy of mine runs 40" Pro Comp extreme muds on his Fummins project truck to get his RPM's right. The truck actually drives great down the road, he's running 18" diameter wheels.

 

[StevoJonesFJ60]

I'd keep it simple and run 35's with the 3.7x gears that should keep you in the sub 2000 RPM range at 65-70 mph range. But then again, those tires might look small since your truck is SOA.

The only problem with that is my gearing options right now are 3.5's that are in the current running gear from the dodge, or I have 4.10 gears in the 14 bolt I picked up.

 

[davegonz]

Ah, I was wondering if you were going to keep the stock 60/80 axles.

 

[boots4]

I run 4.10 on 37" tires with a .75 overdrive and that puts me around 1900-2000rpm at 65-70mph with my cummins 4bt. You're going to have more grunt than I do so stepping up in tire size like a 39-40" should be fine with 4.10s. You'll have a little extra rubber overdrive but that engine is not going to care. If you tow with it you'll probably need to stick to 4th (direct I'm assuming) since for me there are times when overdrive is a little too much and I need to downshift to direct (3rd for me).

 

[StevoJonesFJ60]

Ah, I was wondering if you were going to keep the stock 60/80 axles.

Yeah unfortunately there is no way they would be able to hold up behind the cummins I'm swapping in.

I run 4.10 on 37" tires with a .75 overdrive and that puts me around 1900-2000rpm at 65-70mph with my cummins 4bt. You're going to have more grunt than I do so stepping up in tire size like a 39-40" should be fine with 4.10s. You'll have a little extra rubber overdrive but that engine is not going to care. If you tow with it you'll probably need to stick to 4th (direct I'm assuming) since for me there are times when overdrive is a little too much and I need to downshift to direct (3rd for me).

Good to know, I have to check what trans is available today so then I should know for sure. Max tire size would probably be 39" I might run my 35" tires for the time being until I can get some money for a bigger set. I'm gonna want to go bigger eventually so that's why I want to avoid keeping the 3.54 gearset.