PYROÂ’S 1977 CJ5

November Feature Vehicle

Nov. 01, 2003 By Alex Parker
If you frequent a few of the popular rockcrawling forums on the web, you’ve probably run into Wayne Coatney or “PYRO” as he may be better known. You also know he’s one of the most helpful 4 wheelers out there. He’s always got very helpful technical advise, right down to the part number and common places to find what you need. What you may not know about Wayne is that, behind his helpful demeanor, you’ll find he’s got some serious fabrication talent that he and the Big Island Rock Crawlers ( his shop in Kailua-Kona Hawaii) have applied to his 77’ CJ-5. Whatever they’ve been putting in the coffee there in Kona ( know world wide for its coffee), its worked 2 times at the Hawaii Top Truck Challenge. The Pyro Jeep won the top honors in 2001, in 2002 and almost again in 2003 but un clearly stated rules appear to have thwarted a 3-peat.

 

A stout chevy 400 bored to 421 running on propane, with optional NOS boost. Its enough to make a grown man cry.
So what makes this competition rig work so well? Lets just start with the motor which is a Chevey small block 400 (4 bolt main) which has been bored and stroked to a 421! The mill was stuffed with a forged crank and pistons, H-beam rods, and a Crane cam shaft with roller rockers. Wayne uses a MSD Distributor, coil and controller to fine tune the motor. But thats just the start. This rig runs on a Impco Propane induction system. This mod allows the rig run upside down or at any angle it could possible get into. That wasn’t enough though. Wayne had to take things just that much further with a Victor Jr. Manifold which has been modified for NOS. Yes, thats right, this 421 has Nitrous system jetted for a 200hp shot, which is managed by a Jacobs Mastermind control. With that in mind, i’m surprised NASA hasn’t stolen Wayne’s rig and used it as the new Space Shuttle replacement.

 

The 14 bolt rear with disk brakes, steering brakes, 5.13 gears, and a detroit locker. Also notice the Winch used as an adjustable limiting strap. Trick! Wayne also intends to build a rear steer set up in the near future!
 

The transmission chosen to handle all those ponies was a SM465 4 speed with a LUK clutch. This puts the power to a Advanced Adapters Atlas II with the 4.3 gears and 32 spline outputs front and back. The front drive shaft is a 1350 CV with square receiver hitch tubing going to a rare 1410 yoke on the front axle. The rear shaft of choice was a High Angle Driveline 1480 CV thats capable of a 80 degree angle. This shaft has a 6” slip in it to handle the insane travel of this CJ. The rear yoke used was a 1450 attached to his 14 bolt axle borrowed from a 2 ton dually tow truck.

The 14 bolt has been upgraded with disc brakes, steering brakes, 5.13 gears and a detroit locker. It was then shaved a massive 1.25” for extreme clearance where even the ring gear got a little removed. The front end is a Dana 60 with CTM u-joints, matching 5.13 gears, detroit locker, Dana 70 outer stub axles (35 spline), and Warn drive flanges for brutal strength. The steering set up is a hydro assist done behind the axle by way of custom steering arms by “Ant.” A steering set up like this is needed to push around 42x14.5 Swampers on dual beadlocked hummer rims.

This Dana 60 is ready for some serious abuse with CTM u-joints, 5.13 gears, 70 outer stub shafts, and a detroit locker. Notice the steering is behind the axle and less prone to getting hit. This rig was built with competition in mind.
Now the suspension is stock 77’ Jeep parts. Yea right, I think the Hawaii Top Truck contenders all wish so though. I’ve been told that the only factory jeep parts on the entire rig are the steering shaft and a 5 inch section of the frame rail.
The suspension on the front actually is a outboard spring over with 50” long Alcan springs. The whole front suspension was moved forward 4” to increase the wheel base. The rear suspension is a double tri, 4 link with 2”x.25” walled DOM tubing for the links and stout 1.25” rod ends. The rear springs used are Alcan 1/4 elliptical springs. The total wheelbase for this rig is 99” from hub to hub. More custom work is seen here in that a Warn MX6000 winch is mounted on the back and is often used as an adjustable limiting strap. Pretty trick if you ask me.

 

This is what has the competition running for cover, endless travel suspension!
 

Other mods include a nice new Red paint job, and a Warn 8274 winch is used up front in the unlikely event that this rig should some how get stuck. Also, a full cage (and some frame) made of 1.75” DOM tube has been created to lighten and strengthen up the rig. Wayne and the Big Island Rock Crawlers sure know how to set up a sweet rig. Not only does this rig see some competition use, but its primarily Wayne’s weekend toy where he takes the, what we’ll call a CJ-5 on steroids, to local lava flows for fun!


Check out the fun terrain! No wonder they call Hawaii paradise! I hear the Lava rock is hard on tires though.
Nice crawl of a near vertical slab of a lava flow!
Wayne would like to thank a few of his sponsors that have made such an
awesome rig possible.

- Big Island Rock Crawlers
- Dave @ Poly Performance
- Tim & Chris @ Crane High Clearance
- "Axle Jack" @ CTM
- Parts Mike
- Scott @ RockStomper
- Donny's 4 Wheel Drive World
- Pacific Motor Sports
- OTT Steering
- And, Bubba Burgers!



We at Off-Road.com would like to thank Wayne for his time and we wish you luck at the 2004 Hawaii Top Truck Challenge!



Look to Off-Road.com for more great Featured Rigs every month!

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