Looking for suggestions on 69 FJ55

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

T

TuffMudder

Still working on my FJ55!
10 Year
Joined
Oct 2, 2013
Threads
42
Messages
758
Location
Fort Smith, AR
I'm new to the Mud community and to LC's in general, but I've just bought CarmMontana's FJ55.

I also recently purchased 300 acres of land that is all woods on the side of a mountain. No road access, only an unmaintained and mostly unused easement.

This vehicle will never be a daily driver. I won't be trailering it, so it will be seeing road time driving to the land (30 miles each way) or to some local 4x4 parks (30-60 mile drives).

I want to make this a capable off road rig and able to handle water crossings as well, but this post is just about taking the steps to make it capable off road.

The car already has custom front and rear bumpers, rock sliders, PS conversion and disc brakes up front. I have a Warn 8274 with synthetic rope for the front bumper.

My knowledge of mechanics and fabrication is somewhat limited, but I have a friend who builds dragsters and does custom welding/fabrication for a living and he will be doing most of the work with my assistance.

I will be putting in a 6bt (Diesel is a requirement for me for a couple of reasons), with a NV4500 behind it. I plan front and back SOA's with stock springs, high steer, traction bars, and front and back arb air lockers. Regarding the soa, it is a conversion my welder is familiar with and he will be doing a cut and turn. I have read about these various steps ad nauseum and think I may be to the point that it is all just blending together and causing more confusion than clarity.

I will be extending breathers underneath and adding a snorkel and making sure my fan blade wont turn into a propeller under water, but again, this post isn't about the water prep, just off road readiness.

My goals for this vehicle:
1) Reliable
2) Simple with limited electronics
3) As close to bomb proof as I can get it
4) Excellent off road ability
5) The diesel conversion and arb's already have my bill around $7k. I'll go higher if justified to meet my goals, but this is not a sky's the limit build.

So my questions:
1) Please comment if you see any problems with what I've listed above.
2) I considered Aussie lockers, but think I'd link the arb's more. Feel free to share your opinions on the matter.
3) Please let me know if you think there are additional changes I've not mentioned that I need to consider upfront. In particular, do I need to do anything else to address sway with the SOA conversion, or do the conversion and see how she rides first?
4) The vehicle has a roof rack, and will often be loaded. Any other considerations for stability under load?
5) Any other constructive comments appreciated

Additional plans for this project
- 35" BFG MT's
- Rear storage drawers
- Dual batteries
- Custom gas tank. Largest size that doesn't extend below the frame
- Auxillary gas tank. Probably under the seats

Thanks for the help!

Rodney
 
Last edited:
Factory springs soa with a 6bt will sink those springs. Try to put in some kind of thick leafs mixed in to help with the weight. A front truss wouldn't hurt either. Sounds like a fun build!!

Justin
 
Hi all,

TuffMudder, you will be driving this rig on the highway only a limited amount, so no reason for high $$ parts like a 4bt and NV4500.

You say you want to keep things simple & reliable. I vote for a TBI GM 350 V-8, SM420 or 465, and an Orion transfer case. SOA on big Super Swamper TSLs. Aussie or Lockrites front & rear along with Longfield CV joints.

Good luck!

Alan


>This vehicle will never be a daily driver. I won't be trailering it, so it will be seeing road time driving to the land (30 miles each way) or to some local 4x4 parks (30-60 mile drives).

<snip>

>I will be putting a 6bt (or 4bt if one ends up easier to find), with a NV4500 behind it. I plan front and back SOA's with stock springs, high steer, traction bars, and front and back arb air lockers.

>My goals for this vehicle:
1) Reliable
2) Simple with limited electronics
3) As close to bomb proof as I can get it
 
Hmm, hadn't thought the factory springs would be an issue RLMS. So just mixing up the leaf pack with a few thicker springs will take care of this?

JLC - thanks for the input. I'm going diesel for sure. I think the cummins 6bt has a pretty good reputation for being one of the most bullet proof engines arounds. I doubt I will go 4bt, only if I came across one for less than a 6bt. While that isn't likely, I've kept the possibility open as an option.

As for the transmission, I thought the nv4500 was the best option behind the cummins when considering both expense and durability. I plan to stay manual simply because of simplicity when it comes to repair. I'll talk with my builder. If I can adapt one of those Muncies to the 6bt for less than an nv4500, that's actually a great suggestion.

I have seriously considered aussie lockers over the arb. Simpler and cheaper. I went with arb because I've ready they are a little stronger and I liked the idea of being able to select when I want locked differentials. I've also read some debate about the auto lockers being tougher on your other components. Based on what I've read, it doesn't appear to be agreed upon, but it did give me some pause. Ultimately, I may still go with Aussie lockers as this build is getting expensive FAST.

I'll take a look at the super swampers. Was planning on going with BFG MT's, but not married to that idea

I guess I should have mentioned, I plan to go with 35 inch tires. Possibly with spacers to widen the stance a couple of inches.

Any thoughts on whether I need to address side to side stability any further with this build?
 
If your going to do water crossings dont forget to add lines to vent your axles above the water just like you do for your exhaust and snorkel...
 
Tuffmudder,

Welcome to the group. I look forward to seeing your progress.

The 6bt is very heavy and torquey, you might have problems snapping axles. Look at Longfields for the front and poly performance axles in the rear. ARP studs as well, anything to beef up the drivetrain.

You will find the weak link pretty fast.
 
Thanks Coleman. I intend to extend all breathers on the undercarriage before she see's any road time.

Ron, Thanks for the welcome. I hadn't actually thought the axles would be a problem. Any reason for longfields up front and poly performance in the rear?

I updated my original post and took out the 4bt since Im pretty sure it's going to be the 6bt swap. I also added a few other items I'll be doing with this project that I hadn't added earlier since they weren't really relevant to this thread.
 
Tuffmudder,

Some guys snap the stock axles, on 35's with the stock motor and it has alot less torque. That 6bt is a stump puller. You'll find the weak link, be it a u-joint, axle, knuckle stud, etc.

My way of thought is do it now, rather than on the trail.
 
Hi all,

For a wider stance, and no wheel spacers, consider FJ60 axles. As mentioned before, stuff 'em with upgraded parts for more strength.

If you are worried about axle strength with that Cummins 5.7L I-6 consider army surplus axles from the GM M1008 CUVC pickup. These would be a Dana 60 front & GM 14 bolt rear. Very heavy duty! These CUVC axles are wider than stock 55 Series axles as well.

Regards,

Alan
 
I'd consider a Mercedes diesel from a 300 turbo... Or for that matter, a 3B Toyota motor... It wouldn't be breaking axles all the time and they are excellent off road.

Another mudder built a 55 with a 3b and a toy 5 speed for use in the third world... 33s and beyond just reliable...:D
 
Bobm - I don't actually know how to move an entire thread. Unless maybe you mean just start a new thread?

Scrapdaddy - You guys have convinced me! I'm going to take a look at the army surplus axles Alan suggested and then decided between this vs longfield chromoly superset up front and poly perf in the back. Anyone have any thoughts of what is better between these two options?

JLC - Thanks Alan. I had considered the fj60 swaps, but it just seemed easier to get spacers or custom offsets. Are there any advantages to the fj60 swap? It seems like it would be far more involved. As for the army surplus axles, I'll take a look. I have no idea what the relative advantages and disadvantages there would be between this route vs the longfields and poly perf that Ron mentioned. Any thoughts?

bikersmurf - I had considered the Mercedes diesel, but honestly, it and the 3b don't seem to be as common around here (fort smith, ar), and I think i'd end up having to pay quite a bit more to go those routes. That being said, I will definitely take a look and see if I can get either for a similar price. One of the things that drew me to the cummins 12v was its long standing reputation for being bulletproof with little to no electronics both of which are huge pluses for me. I don't really know how the Mercedes or 3b compare in those respects, but I'll do some research.

As for the keeping it simple. I do feel like I'm making this more difficult than necessary. Not sure how to remedy that given what I'm trying to accomplish...

Rodney
 
Ok, the vehicle is 2-3 weeks from being in my driveway, here is where I stand currently with suggestions incorporated. (Sorry if this seems overly redundant. Reposting like this helps me to sort through everything).

Already on the vehicle or purchased:
  • Custom Front bumper with winch mount and recovery points
  • Warn 8274 winch
  • Custom Rear bumper with Spare tire and Jerry can holder
  • Roof rack
  • Rock sliders
  • Power steering conversion
  • Front disk brake conversion

Planned mods relevant to this thread:
  • Diesel Swap - currently 6bt with nv4500
  • SOA with cut and turn, extend out rear sway links and add quick disconnect, widen stance (probably spacers or custom backspacing), traction bars, probably add thicker leaf springs to avoid sag?(i've read a number of soa threads that stuck with stock springs, but then again, they werent considering a 6bt)
  • Hi steer
  • Extended break lines
  • Aussie lockers unless I find a great deal on ARB air lockers
  • 35" tires
  • Longfield chromoly front axles/birfs
  • Poly Perf rear axles
  • ?Undecided on transfer case?

Planned mods not relevant to this thread:
  • extend all undercarriage breathers
  • Snorkel
  • Clutch style fan
  • Dual batteries
  • Custom long range tank
  • Auxillary tank
  • Custom rear storage drawers
 
Lol, you people are making this so hard on me! But then I suppose this is exactly why I posted here. I did a lot of reading and new the 6bt had its down sides, but honestly, as I said in my original post, I've read through so many threads, everything is getting fuzzy.

Ok, so I'm going to go back to the drawing board on diesel choices.

6bt - big, heavy, torqie (is that a word?), bulletproof and voted as one of the top engines for surviving the zombie apocalypse (personally I think the Canadians are a bigger threat. You can't trust any nation that's that nice!).

4bt - 4 cylinder version of 6bt. Seems to have all of its pluses but none of its minuses. Downside, harder to find around here and generally significantly more expensive

Mercedes 300td - does this thing have the power to push a loaded fj55 like what I'm trying to build? Don't know, but should be reliable and not too expensive. Not sure how ch trouble it would be to match it up to my fj55

Toyota 3b - these are more myth than anything else around here. Not sure I could even find one. Harder to find parts for and repair (which is a huge consideration for me), and I'm assuming far mor expensive. As far as the actual swap goes, it's probably perfect

Isuzu diesel - I've heard a lot of people like these, but honestly I know nothing about them.

So, IF I can find one at a reasonable price, I'm probably leaning more toward the 4bt right now.

I don't claim to be any type of expert on diesels, so all of this info is just based on the reading I've done in prep for this project. Feel free to correct any errors I've made

And thank you guys for all of these great replies. It's help me a ton...I think

Rodney


Sent from my iPhone - now Free
 
The 69 is coarse splined I believe. If I'm getting a new differential and new axles up front, can a change over to the 30 spline? If so, there is a set of lock rights for sale with the "newer" spline pattern


Sent from my iPhone - now Free
 
It was mentioned that this thread would be better suited to the pig forum. How do I go about moving the thread over?
 
Thanks scrapdaddy
 
You must log in or register to reply here.

Share this page

Back
Top Bottom