Recommended Rockcrawler frame? FJ 40 or Suburban

[kfrosty]

I've been trying to plan my first rock crawler project as I have time. I had initially purchased a 1980 FJ 40 rolling chasis but after research decided I needed dana 60 axles.

In looking found it was cheaper to just purchase somebody elses project versus trying to buy everything piece by piece which led me to buy a 1991 Suburban with all the components I'm looking for. Dana 60's, 350 TBI, T350, NP 205 etc.

No to my question, since the drive train is already bolted to the GM Frame, I've been thinking about just cutting the body off and shortening the frame and then having a tube chasis built on top of the frame.

Think the pro's of this are not having to remount engine, transmission etc. Plus I would think the frame of the suburban is going to be a lot stronger than the FJ 40.

However, the FJ 40 chasis I have already has a firewall attached. I'm thinking possibly putting the aprons and an extra hood I have on it so the front looks like a 40 and then have a tube cage, tub for the back. So I suppose I could potentially enclose it for the winter.

The negatives are I have to blast and paint the frame. Also, I not sure I care for semi boxed frame which is going to be a haven for mud. Not sure the frame on the Toyota sturdy enough for 44's and 350 with 5:13 gearing in the rear. (Suppose the cage/exo tied in would strengthen it.)

That's what I've thought up between the two and still on the fence. Hoping others may shed opinions and thoughts about benefits of one over the other or possible gotta's to look out for.

Thanks.

 

[woody]

honestly, neither one.....if you are truly building a rockcrawler, then both frames create compromises that you want to avoid....

IMO, square 2x4 tubing for the main rails, parallel from front to back....2x4's for the front and rear and bib crosstubes, then .120 wall tubing for the undersupport structure.

I've lived with the limits of the FJ40 frame for too long, and the Suburban frame would IMO be worse.

 

[kfrosty]

Even if the surburban was shortened? Not doubting you but could you shed some light on the compromises? My thinking is the frame would give you something to build off of and you wouldn't have to bother with the mounting of the drivetrain. I was thinking about raising the tranny/tcase mount so the bottom is flush with the frame rails and I could plate the bottom.

Also, keep in mind I'm not planning on competing or anything. Just something to take to the trails around here and I don't want to have 20k + tied up in it.

Of course going with 2x4 tubing, I would consider but the thing that concerns me is not getting things lined up properly, strenghtened correctly, etc.

BTW, brings another question to mind. This may sound corny but is there a good book or literature anywhere on building a rock crawler?

I'm fighting a fine line. On one hand I'd like to put something together I can enjoy in the spring. But at the same time I don't want to get in a situation to where I have to build it 10 times because I didn't know what I was doing and having things break on me everytime I take it out.

Thanks.

 

[WES1977]

How about these guys?
http://www.matkinsextreme.com/FJ40's/FJ40's.htm

 

[kfrosty]

Thanks Wes,

Not looking to buy one, just trying to figure ou the pro's and cons of shortening the suburban or going with the FJ.

I would have thought the suburban would have had a stronger frame. If the problem would be flex, I would think you could overcome that with supports and tying it into the tube body.

Now I'm curious as to how 2x4 tubing for the frame might posibly be better?

 

[Arya Ebrahimi]

I would buy the suburban for its components and then fabricate a chassis to put all the stuff in. Woody is right, both of the stock frames have their compromises.

 

["N8"]

2nd that either fab up a crawler frame for the components or go find a wercked fzj 80 pull the frame and then give all the other stuff to us.

 

[kfrosty]

Ok, thanks for the info. I figure with me having to learn how fab everything, might be quite a while but I'll look into that.

My garage isn't the biggest right now and all I have is a miller 250 and miller plasma cutter. For you guys that just decided to fab your rc's, how did you go about researching and learning to make sure you did it right. I've been searching and there are tib bits here and there but nothing that makes me comfortable that I could get something decent the first try.

Any pointers would be appreciated.

Also, I'm assumming I'll need a band saw, tube bender and notcher. Anything else I should be budgeting for?

Oh yeah, the tube bending software that's out there. Any recommendations as to how it would be on designing the chasis and cage?

Thanks.

 

[Arya Ebrahimi]

Become a member of Pirate and read read read. That's how I did it. Once you've thought you've read enough, read some more, and then start searching to answer your questions.

 

[DHONDAGOD]

What ARYA said...... My reccomendation is if your planning on cutting up the sub is to wheel the crap outta it with the body still on it... youll learn alot and have a good time doing it.... Use the body as one big rock slider...No fear of body damage.... In the mean time, read, read, read...
Couple threads going right now on "post up buggy picks" in general 4x4 and the landcruiser forums on pirate.....

Build your chassis, then on your off season, pull the stuff from the 'burb carcass and transfer it to the chassis...


Chris

 

[HI^C]

my $.02

91 burb, double check what you have, NONE of those items came factory in a 91 well the TBI. D60 rear 98% is 30 spline 1.30 YUCK toss it out.

you have equal trouble with trying to shorten a frame as you do from making a frame from scratch, no problems doing one the other isnt that much different.

2x4 .083 is what i build frames out of, last one i did was a heep on 104 wb with bumpers on the end like 155 overall i think it was just around $115 for 2x4 rails two cross, and then 2x2 bumper rear and shock mount COST was steel.


if your just doing a tube buggie build from scratch and leave bodies out of it, your doing a cruiser cruiser frame or scratch, doing a swamp buggy or a 10-15" Narrowed 4 door bobbed burban then burban frame do a structural cage in it.

sounds like a leaf leaf setup, reg. frame, leaf link then i would go 3/4 frame or from scratch.


$$$, time, and what you want in the end is all that really matters. Getting there is a direct factor of all the above.

 

[cntryguy]

go to pirate 4x4 and find the buildup in the toyota section under the sticky at the top for "kate 6.0" this guy built a sweet ass cruiser that is half tube half stock cruiser frame. You said you have a firewall and that is just about all he started with from the fj40. If nothing else it is a sweet ride.