Build Thread 1981 CJ7 Trail Rig Build

[CJ]

That's one heck of an update!
Two cars gone and one added, your busy...

That's is sum flex!

 

[Belizean]

Busy ! Jeep looks just right flex wise. Go for it !

 

[Nikwho]

Well, another big update! After building the perfect "sweet spot" Jeep, with perfectly functioning hydro assist steering, an NP203/Dana 300 doubler Transfer Case and 270:1 crawl ratio, and the best performing leaf sprung rig I've ever ridden in, and after a few flawless wheeling trips, I blew the entire thing apart a couple of weeks ago!

I'm swapping to one tons and 40" tires, 4 linking the front, goimg to full hydro steering, full custom roll cage and an Atlas Transfer Case !

Yeah, I think that I'm kinda dumb, too!

Pictures to follow...

 

[Nikwho]

Oh yeah, I'm swapping in a fresh Gen 1 small block Chevy 350, with a new Holley Sniper EFI system AND stretching the tub by roughly 12"-16" (to be determined once I cut it up, and figure out what looks best). The only thing that I really don't like about this rig is having zero storage space! The little bit that you would usually have is taken up by my fuel cell that is inside my tub! So, gonna change that. And, gonna try to go fairly quickly, as I intend to run the Rubicon and Fordyce trails this September!

 

[Nikwho]

Okay, last bit of update, then back to turning wrenches and melting metal together!

14 bolt disc brake swap is done, truss ready to burn on. Going with 5.38:1 gears and a spool.

My Dana 60 front axle is about ready! It's a '99-'04 Super Duty high pinion drivers side drop axle. Bought it from my buddy, already trussed and with a brand new PSC 8"x2.5" double ended full hydro ram. Bye-bye bump steer! It's got all the chromoly goodies, ball joint eliminator, and swapped to 35 spline outers. It will run a spool and 5.38 gears, too. Going to do some high end disconnects, so that I can disengage the front axle as neededIfi think that it should turn okay with the large full hydro ram. If not, I'll yank the spool and run a Detroit locker and slugs, to replace the disconnects.

I plan to run the Atlas behind my NP203 doubler. The Atlas is less likely to be yard saled by the double down healthy SBC! I'll have plenty of wheelbase, since I'm doing a wheelbase stretch with the rear 4 link, though I have enough room now, with my current doubler setup, even without a double cardon rear driveshaft.

Cage should go in today. Will post pictures when done!

Then I will be mocking up my four link brackets, and making sure that it will fully flex my 14" Fox coilovers! Once I've stuffed a double triangulated four link up front, and am happy with how it flexes, I'll measure for my front driveshaft, and figure out where I can tetris in some hydraulic bumpstops and some limit straps, to protect my shocks!

 

[Nikwho]

 

[Belizean]

I think you should have kept that one and started with a clean slate. But I guess September is actually pretty close.

 

[Nikwho]

Yeah, this version was originally going to be a tube chassis rock buggy (I have the chassis), then was going to be an old VW Rabbit pickup truck, but my wife and son (and myself) really like this old CJ, and I only want to maintain one rock crawler, so, I ripped it all apart, and made it what I really wanted it to be.

 

[gert]

Man i still cant get over the crawl ratios your gonna have


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[Belizean]

Man i still cant get over the crawl ratios your gonna have


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Don’t be jealous. Mine is 1/2 of yours. That is a pretty amazing number though.

 

[Nikwho]

Got the cage in the rig today. Regarding the fabric on top of the cage, I took some measurements and laid out a sunshade that will be made out of 90% solar fabric. Taking the fabric to the upholstery shop and having them sew it up, so I have some shade on the trail.


At this height, I'd have a 20" belly clearance, and it sits about 4" lower than it did on 37's!!! I'm going to try to keep my ride height as low as possible.

 

[Belizean]

View attachment 101332
At this height, I'd have a 20" belly clearance, and it sits about 4" lower than it did on 37's!!! I'm going to try to keep my ride height as low as possible.

That clearance is great while lowering it. I drove a Scrambler with SOA and about 6 inches of lift and on 35s and at one point I felt like I was going to flip on it’s side.

 

[Nikwho]

Man i still cant get over the crawl ratios your gonna have


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The Jeep had the 270:1 crawl ratio in its previous configuration (6.68:1 first gear X 2:1 doubler X 4:1 LoMax Dana 300 gears, X 4.88:1 axle gears) but will now be 309:1 with the new setup! (6.68:1 first gear X 2:1 doubler X 4.3:1 Atlas, X 5.38:1 axle gears). It's fun, for sure! Super controlled through technical rocks.

 

[gert]

The Jeep had the 270:1 crawl ratio in its previous configuration (6.68:1 first gear X 2:1 doubler X 4:1 LoMax Dana 300 gears, X 4.88:1 axle gears) but will now be 309:1 with the new setup! (6.68:1 first gear X 2:1 doubler X 4.3:1 Atlas, X 5.38:1 axle gears). It's fun, for sure! Super controlled through technical rocks.

I feel like you could probably get out and spot yourself through obstacles lol


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[Belizean]

I feel like you could probably get out and spot yourself through obstacles lol


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Maybe get out and have dinner.

 

[Nikwho]

Yeah. That ride height is the goal, however, it'll probably end up about 2" higher, which would give me a 22" belly height. I'll know more after getting the front four link mocked up. Either way, I'm going to get it to sit equal to or lower on the 40" tires, than it did on 37's. I'm looking for about 5-6" of up travel on my coilovers, and 8-9" of droop.

 

[Nikwho]

I feel like you could probably get out and spot yourself through obstacles lol


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It's nice! Since I've had that 270:1 crawl ratio, I've never stalled the Jeep. It's definitely a game changer. No bouncing, very controlled and calculated. People talk about breaking parts with super low crawl ratios, because of the torque multiplication, but I forsee it saving a lot of parts. It changed how I'll build rigs moving forward. I LOVE the super low crawl ratio! Highly reccomended!

 

[Nikwho]

Okay, time for ANOTHER update. This project has completely snowballed. I 100% should have left this Jeep exactly how it was and started a fresh build! At this point, I am literally only re-using my Jeep tub, windshield frame, seats, fuel cell, and NP203 doubler! Literally everything else is gone. Started fresh with a YJ chassis (okay, about four feet worth of a YJ chassis).

Up front is a Moto-Bilt YJ front frame section. It angles up quite a bit more than the factory frame up, allowing for more up travel, and a lower ride height. So, I'm going to utilize the boxed YJ frame only from the firewall to where the third body mount, where the factory frame turned up for the rear axle. It's fully boxed. I'm utilizing some back-half brackets from Dave's Custom Unlimited to bring the frame up more than stock, and will bring each frame rail in between 3"-4" per side, to allow for more room for shock packaging. Behind these new brackets is some fresh 2"x4" square tubing.

Previously I believe that I extended from the stock 93" wheelbase, to somewhere right around 106". Basically +7" stretch on both front and rear axles.

I will be added roughly 10"-12" MORE wheelbase! I'm tentatively looking at landing between 117"-118" wheelbase at full compression, which should end up somewhere around 116"-117" at ride height.

I've been working on double triangulated four link systems front and rear. Really wanting to avoid a panhandle bar up front. During my first mock up/tack weld session, I landed at 36° of total triangulation between the front upper and lower link bars. That's not QUITE enough to be unanimously considered enough separation angle to keep the axle located securely. So, I've been tweaking some things, playing with link length, engine position, and link mounting locations. I'll have more solid numbers tomorrow, but shooting for total link separation angle of 40°+.

 

[Nikwho]

Made a lot of progress over the past couple of days, despite coming home from work with a 103° fever last Wednesday. Here's a shot of the frame after flipping it upside-down. I was doing some final welding on the Moto-Bilt front frame section, the Dave's Custom Unlimited rear-half brackets, the 2"x4" new rear frame rails (extended), and some link brackets. The rear link brackets that you see here are not final locations. Those were pre-existing leaf spring hangers, and if used with the link length that I want to go with, would put me at nearly a 125" wheelbase. Too long. I've got new link brackets ready to burn in tomorrow. I've spent about four or five hours today measuring and plugging numbers into my 4 link calculator. I'll share those files when I get everything finalized.

 

[Nikwho]

Here's a peek of when I was extending the frame using the Dave's Custom Unlimited brackets and 2"x4" tubing. Lots of work to shim the frame to perfectly level, and getting the new rear frame rails squared up and parallel to the middle section of frame.