Project ROKTOY - Summary

http:/www.4x4wire.com/toyota/projects/roktoy12/

Short Cuts

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By: Jay Kopycinski - 6/2003

Project ROKTOY rolled out of the garage and onto the its first trail in November 2002. Since that time it has run numerous Phoenix area trails, Johnson Valley, and the Las Cruces area trails.

It all started with this

The rig sits very close to the frame height that my truck did, as I designed it. I am running the same suspension that I had on my truck. It worked well for me so I decided to stick with it. I am also still running the RS9012 shocks I had on my truck. However, I plan to swap over to Bilstein 5100 gas shocks. These should provide a little tighter handling over the fast stuff.

The wheelbase is 10" shorter and the rig is more manueverable. Overall, I really like the 106" wheelbase for the terrain I most commonly wheel. Visibility over the hood is no better than in my truck. But, visibility everywhere else is great. I can completely see both driver side tires. Gets a little dusty with no windshield, but wheeling in the open is great. The whole character of the vehicle is different. I no longer feel like I'm in a conventional truck.

Brakes work really well in the configuration I built, without a booster or propotioning valve. The V8 engine pulls strong and provides great torque. WIth 4.10 gears I find I can run dirt roads in high range or in 2.28:1 low range.

The hydro assist steeering works like a dream and even has good return to center. This is an awesome mod and very inexpensive if you gather your own parts and do your own build labor.

Raising the transfer case up higher in the chassis improved the underbelly clearance and makes a big difference in breakover angle. Keeping all the crossover and skidplate pieces tucked up high leaves fewer frame spots hanging out to catch rocks. The poly engine mounts and the tighter transfer case mount hold the drivetrain much more solidly than the the stock Chevy engine mounts and stock Toyota transfer case mounts I had before. This is a significant improvement. There is no driveline rock and the transfer case shifters sit nice and steady whereas my old setup would torque side to side under changing load.

Fully loaded with a full tank of gas, 36" spare tire on steel wheel, Hi-Lift jack, and storage box full of tools and trail spares, the rig weighed in at 3780 lbs. Heavier than I expected (hoped) but still not too bad for a recreational trail rig.

The front suspension does not flex quite as well as it used to. I think that is a sign that the front end is truly lighter. I went from a V6 in my truck to a V8 in the buggy, figuring I added 80-100 lbs. in engine weight. However, I shed coinsiderable weight up front in the form of cab sheetmetal structure, glass, bumper, and a fully populated dash area. I can't flex the front suspension to the bumpstops as easily as I used to but it articulates well on the trail.

The rear supsension also does not flex quite the distance it did on my truck, but still does a good job of keeping the tires down in most cases. My old track bar is still in use and keeps the rear axle from wrapping up. Each rear tire does rub one of the support tubes in the back. Eventually I'll cut those tubes out and move them to fully clear the tires. I don't know how much more my old frame contributed to articulation, but it may have been a little. The new chassis is certainly more rigid than my old truck frame.

The most common questions people ask me about this project are: (1) Why start with a stock (heavy) frame instead of a scratch-built frame, and (2) Why didn't I build it with coilovers and 4-link suspension?

I had never done a project of this magnitude or nature, so starting with a stock frame gave me a solid baseline from which to work. I knew my truck suspension and how to easily move it over to a new frame with some minor mods. Starting from scratch and building a complete custom tubular chassis would have been considerably harder. I figured I had plenty of work on my hands figuring out how to bend tube and do the rest of the chassis.

Building a linked suspension would have also required considerably more design time, fabrication, and expense (~$3k more). Since this is a trail play buggy, I decided to stick with my current leaf spring suspension.

I built nearly the entire project by myself and estimate I spent about 500 or so hours completing it. Net cost, starting with my truck as it was and buying and selling parts as needed, came to about $3000. This does not include the cost of new wheels and tires. Nearly all leftover pieces of my truck were parted and sold.

Did I meet my goals?

My goals were to shed the stock sheetmetal along with what weight I could, gain visibility, and more engine power. There was no thought of building a competitive rig. This was meant to be purely recreational with space to carry a cooler, spare parts & tools, extra clothes, and even have room to lash down some camping gear should I want to stay overnight on the trail.

I feel I met most all my goals and expectations and the rig has shown itself to be reasonably capable running dirt roads, mild sand dunes, and some hard core rock trails.

So....what would I do different?

If I were to build another rig such as this I would probably build the entire chassis from scratch. However, not having the experience I have now, I still feel it was a very good idea to build this rig starting with a stock frame.

I am very pleased with all my drivetrain and gearing choices. Engine placement works well and I like the weight distribution. Someone more used to, and fond of, a Jeep engine placement might want the engine a little further back in the chassis. The fact that I have the extra weight of the spare tire and storage box in the rear keeps the rig reasonably well balanced.

What's next?

Except for shock mount rework to accomodate the Bilstein shocks and the addition of some aluminum roof panels, I'm pretty happy just wheeling for a while......but who knows?

Thanks for reading!