Comanche MJ: The 1986-92 Cummins-Powered Jeep

The 1986-92 Jeep Comanche MJ was one of Jeep’s better ideas. Essentially an XJ Cherokee with a pickup bed, the Comanche even had a factory diesel option for the 1986 and 1987 model years, though today those engines are about as rare as hen’s teeth.

Donald Bankston loved the Comanche but knew that even if he could find one with the original Renault-sourced 2.1-liter turbo diesel, its 85 horsepower wouldn’t be nearly enough to satisfy him. Like many Jeepers and dieseohaulics, Bankston’s philosophy is “if you can’t buy it, build it!” He paid $200 for a gutted 1992 4×2 MJ from New Mexico and set to work.

The Comanche’s limited engine compartment space left few choices for a diesel powerplant. Bankston focused on the Cummins 3.9-liter 4BT four-cylinder because of its compact size, simplicity, easy adaptability, and the fact that it makes good power with room to grow. The Cummins fours most commonly seen in vehicles are the 105-hp/300 lb-ft 4BT and the 120-hp/325 lb-ft 4BTA. The primary difference between the two is that the 4BTA has an intercooler (the “A” stands for aftercooled) and uses higher fuel rate settings.

Bankston scored a 4BTA but had to buy a 1987 Grumman-bodied GM chassis box van to get it. The engine was a 1993, indicating the van was one of the many that had been repowered. (Here’s a clue for 4BT seekers: many 1980s box vans on GM chassis originally mounted GM 6.2L V-8 diesels, but the commercial workload proved too much for them and many died young. A cottage repowering industry emerged and the Cummins 4BTA was a popular choice as it was powerful, economical and durable enough for the job—not to mention small enough to fit under the doghouse.)

The beauty of the 4BTA is that it’s basically a 6BT with two fewer cylinders. The mountings are the same as the 5.9L Cummins, or nearly so. Bankston used the rear adaptor plate, flywheel and clutch from a Dodge 5.9L application to mate his engine to an NV-4500 five-speed from a 2000 Dodge 3500 4×4. The rubber engine mountings are first generation Cummins-Dodge pieces, and Don fabricated the chassis brackets from 3/16-inch plate, forming them to fit along 9 inches of the front frame rails on each side. He took care here because the Comanche MJ combines the front unibody section of a Cherokee XJ from the firewall forward with a conventional ladder chassis in back. The fabbed mounts spread the 800-lb weight of the engine over a larger section of chassis, using many of the original mounting spots and a few new ones. That ensured no problems due to weight or torque.

The 4BTA is a tall engine. No firewall or radiator support modifications were needed, but in order to simultaneously close the hood and have the oil pan clear the front axle and track bar, Bankston needed 4 ½ inches of lift. He reckoned the oil pan and oil pickup could be modified, but that would reduce oil capacity. Besides, he wanted enough of a lift for 33-inch tires.

The exhaust system is 3-inch mandrel bent from the turbo back with no muffler. Bankston bought several tailpipes for 1998-up Dodge ¾-ton vans at $20 each. This gave him all the bends and straight sections he needed to cut, weld and fabricate his exhaust system.

To keep the Comanche Cummins cool, Bankston used a three-core HD cooling aftermarket radiator in the original mounts with a set of triple 9-inch electric fans. Bankston reports the engine runs cool as a cucumber in all conditions.

Wiring a mechanically injected diesel is easy and Bankston was able to re-use the donor truck’s original Delco 15 SI alternator and starter. The chassis wiring was a bit of a problem because of the electronic speedometer used in 1989 and later Comanches. The answer was simple: Bankston pulled the wiring harness and mechanical speedo from a rust bucket MJ parts vehicle.

Bankston was justifiably worried the original Jeep NP-231 transfer case wouldn’t hold up, so he built a heavy-duty NP-241 series case from new and used pieces, incorporating a 1 1/2-inch chain from the Dodge NP-241D, a six-pinion planetary set and 32 spline shafts. (The transfer case alone probably deserves its own article.)

The axles are the stock units, with a D30 high pinion converted to 297-size shafts and U-joints in front and a Dana 44 in the rear. Unfortunately, these lightweight axles haven’t held up well to the Cummins’ torque and Bankston’s heavy right foot, so they will soon be swapped out for Dana 60s. But the 4BT likes the 3.55 gears, and Bankston is happy with the 33×12.50-15 Goodyear Wranglers, which he has mounted on 15×10 Eagle alloys.

Once the engine was installed and the shakedown tests completed, he began tweaking the little Cummins. At present, it’s making a dyno-tested 162.4 hp at 2,374 rpm and 393.4 lb-ft of torque at the rear wheels. In a 4,050-lb truck, that’s “yeehaa” territory. Bankston has a hard time not boasting that the power bump cost him only $85. He simply installed a 3,200-rpm governor spring in the Bosch VE rotary pump, turned the fuel up and swapped out the original 16cm3 exhaust housing from the Holset H1C turbo with a used 12cm3 housing from a Dodge 6BT. The new setup spools a lot faster and makes about 30-psi maximum boost.

One of the best parts about the conversion has been the fuel economy. Driving like a bank robber on the run, Bankston has recorded a low of 24 mpg. Driving like Scrooge with a license, he’s recorded 36 mpg. His usual average in mixed driving is 26-28, including lots of short hops. So far, he has put some 20,000 miles on the conversion with no trouble. Don says the conversion is easily doable for any MJ or XJ Jeep owner with moderate wrenching skills. When asked for specific advice to prospective swappers, Bankston replies dryly, “Don’t test-run a diesel on the floor… they’re hard to catch!” DW

FREQUENTLY ASKED QUESTIONS

What are the best-selling products for Jeep Cherokee XJ and Comanche MJ from 1984-2001?

Top-Selling Upgrades for Jeep Cherokee XJ & Comanche MJ (1984-2001)

Discover the must-have accessories to enhance your Jeep Cherokee XJ or Comanche MJ. Featuring high-quality components, this selection caters to Jeep enthusiasts seeking durability, performance, and style.

1. Battery Tray Bolt-In

Price: ~$78.24
Popularity: 283 reviews

A reliable choice for replacing that worn-out battery housing, ensuring your battery stays secure and stable.

2. Steering Gear Box Spacer

Price: ~$54.16
Popularity: 62 reviews

Upgrade your steering setup with this heavy-duty spacer, perfect for off-road enthusiasts who demand precision.

3. High Clearance Steering Kit

Price: ~$419.93
Popularity: 79 reviews

Elevate your off-roading capabilities with this comprehensive steering kit, designed for enhanced terrain navigation.

4. Front Bumper Tie-in Brackets

Price: ~$46.95
Popularity: 53 reviews

Add strength and stability to your bumper with these robust tie-in brackets, essential for serious off-road adventures.

5. Electric Fan Shroud Conversion

Price: ~$138.43
Popularity: 52 reviews

Optimize your vehicle’s cooling system with this aluminum fan shroud. Compatible with three 10″ fans, including popular options like Mishimoto.

6. Stump Winch Bumper

Price: ~$475.01
Popularity: 51 reviews

This durable winch bumper offers unparalleled protection, perfect for those who demand high performance and rugged style.

7. DIY Stump Winch Bumper Kit

Price: ~$270.87
Popularity: 43 reviews

Embrace your inner mechanic with this kit that allows for a custom touch while ensuring robust front-end protection.

8. Battery Hold Down Bracket

Price: ~$26.43
Popularity: 31 reviews

Keep your battery secured with this CNC-cut bracket, providing peace of mind on every adventure.

9. Front Bumper Builder Brackets

Price: ~$66.21
Popularity: 31 reviews

Perfect for the DIY enthusiast planning a custom bumper build, these brackets simplify the installation process.

10. Manta Ray Rear Bumper

Price: ~$615.41
Popularity: 23 reviews

A blend of durability and functionality, this rear bumper is designed specifically for the Jeep Comanche MJ, offering superior protection.

11. DIY Manta Ray Front Winch Bumper

Price: ~$399.41
Popularity: 17 reviews

Elevate your Jeep’s style and performance with this DIY kit, allowing for a tailor-made aesthetic and function.

12. Driver Side Battery Tray Mount Adapter

Price: ~$25.26
Popularity: 12 reviews

Ensure a perfect fit for your battery tray with this mounting adapter, seamlessly integrating with universal trays.

These products are favored among Jeep Cherokee XJ and Comanche MJ owners for their quality and practicality. Elevate your Jeep with these top picks today!

What solutions are available to strengthen the front bumper of a Jeep Cherokee XJ or Comanche MJ?

Solutions for Strengthening Your Jeep Cherokee XJ or Comanche MJ Front Bumper

If you’re looking to enhance the robustness and stability of your Jeep Cherokee XJ or Comanche MJ’s front bumper (models 1984-2001), several effective solutions are available. These options are perfect for off-road enthusiasts who demand more from their vehicles.

1. Heavy Duty Frame Tie-In Brackets

Frame tie-in brackets are designed to fortify the connection between your bumper and the vehicle’s frame. They provide additional support, improving overall stability and reducing wear on the steering box. If you’re dealing with rocky trails or rugged terrain, these brackets are essential for keeping your bumper securely attached.

2. Front Bumper Builder Brackets

For those interested in crafting a custom bumper, front bumper builder brackets are indispensable. These brackets simplify the process, providing a solid foundation to build upon. With these, you can kickstart your custom build with confidence, ensuring that your new bumper is both durable and precisely fitted to your Jeep.

3. Reinforcement Kits

Consider kits that include various components such as gussets, additional brackets, and mounting hardware. These comprehensive kits offer a turnkey solution for increasing bumper strength. They are particularly useful if you’re looking to distribute stress across a larger area, reducing potential damage during heavy use.

4. High-Strength Steel Components

Using high-strength steel in brackets and reinforcement pieces is another effective way to enhance durability. Steel components are generally more resistant to bending and breaking, making them a smart choice for those who frequently encounter challenging driving conditions.

By opting for one or more of these solutions, you can significantly increase the protective capabilities and longevity of your Jeep’s front bumper, making your off-road adventures safer and more enjoyable.

What products can help simplify the process of building a custom bumper for a Jeep Cherokee XJ?

Essential Tools for Custom Bumper Construction on a Jeep Cherokee XJ

Building a custom bumper for your Jeep Cherokee XJ (1984-2001) can be a rewarding project. Whether you’re crafting it for functionality or aesthetics, having the right products can make the process much smoother. Here are some must-have items to simplify your build:

1. Bumper Mounting Brackets
   Start off with high-quality bumper mounting brackets. These critical components provide a secure and precise attachment point for your custom bumper, ensuring stability and proper alignment.
2. Steel Plates and Tubing
   Opt for durable steel plates and tubing. These materials form the backbone of your bumper, giving it strength and resilience to withstand off-road adventures.
3. Welding Equipment
   Reliable welding equipment is essential for assembling your bumper. A MIG welder is often recommended for its ease of use and strength of weld.
4. Grinder or Cutting Tools
   Precision cutting tools like angle grinders are invaluable. They help shape your steel components, allowing for custom designs and perfect fits.
5. Measuring and Alignment Tools
   Accurate measuring tools, such as calipers and measuring tapes, are necessary to ensure every piece fits together seamlessly.
6. Rust-Proof Coating
   Protect your investment with a quality rust-proof coating. This extends the life of your bumper by preventing corrosion.

By utilizing these tools and materials, you can build a strong, custom bumper for your Jeep Cherokee XJ that meets both your needs and your style preferences. Happy building!

Are there any DIY kits available for building a winch bumper for a Jeep Cherokee XJ or Comanche MJ?

Build Your Own Winch Bumper for Jeep Cherokee XJ & Comanche MJ

Looking to enhance the functionality and appearance of your Jeep Cherokee XJ or Comanche MJ? Consider a DIY Winch Bumper Kit for your build. Below are two popular options that cater to Jeep enthusiasts eager to personalize their off-road experience.

1. Customizable Stump Winch Bumper Kit

• Price Range: Around $270
• Compatibility: Fits Jeep Cherokee XJ & Comanche MJ (1984-2001)
• Features:
  • A robust build designed for durability and rugged use.
  • Perfect for hands-on Jeep owners who relish the satisfaction of building their own equipment.
  • A cost-effective alternative that doesn’t compromise on quality or style.

This kit provides everything you need to take control of your Jeep’s front-end capabilities, from mounting hardware to detailed instructions.

2. Manta Ray Front Winch Bumper Kit

• Price Range: Approximately $400
• Compatibility: Suitable for Jeep Cherokee XJ & Comanche MJ (1984-2001)
• Highlights:
  • Offers a sleek, aggressive look while boosting performance.
  • Includes components for an upgrade that enhances both style and utility.

This DIY kit allows you to unlock the full potential of your vehicle, ensuring it stands out both on and off the trail.

Both options provide all necessary materials and guidelines, making them ideal for hobbyists dedicated to improving their vehicle’s look and performance. Whether you’re after a more rugged feel or a stylish upgrade, these kits offer a rewarding project for the adventurous Jeep owner.

What products are available for upgrading the battery housing in a Jeep Cherokee XJ or Comanche MJ from 1984-2001?

Battery Housing Upgrades for Jeep Cherokee XJ & Comanche MJ (1984-2001)

Are you looking to enhance or replace the battery housing of your Jeep Cherokee XJ or Comanche MJ? Explore these top-quality options designed specifically for models from 1984 to 2001:

1. Direct-Fit Battery Trays
   • Steel Construction: Provides enhanced durability and resistance to corrosion.
   • Bolt-In Design: Simplifies the installation process, eliminating the need for modifications.
2. Reinforced Brackets
   • Heavy-Duty Materials: Ensures stability and longevity under all driving conditions.
   • Precision Fit: Tailored specifically for the Jeep Cherokee XJ and Comanche MJ models, ensuring a secure fit without additional adjustments.
3. High-Performance Hold Downs
   • Adjustable Straps: Designed to accommodate a range of battery sizes.
   • Quick Release Mechanisms: Facilitate easy battery replacement and secure retention.

Benefits of Upgrading:

• Improved Battery Security: Prevents movement that can lead to damage during off-road adventures.
• Enhanced Vehicle Performance: Reliable power delivery with a stable battery.
• Protection Against Wear and Tear: Keeps components safe from the elements.

Choosing the right battery housing upgrade ensures your Jeep is always ready for the next adventure, providing peace of mind both on and off the road.

What options exist for securing a Jeep XJ/MJ’s battery in place?

Options for Securing a Jeep XJ/MJ’s Battery in Place

When it comes to keeping your Jeep XJ or MJ’s battery securely anchored, there are several reliable options that provide both safety and convenience. Here’s a breakdown of the top solutions:

1. Custom Battery Trays

• Material & Design: Many custom trays are made from durable materials like aluminum or steel and are precision-cut for an exact fit.
• Benefits: They offer a snug fit, preventing battery movement during off-road adventures. Look for models with rust-resistant coatings for longevity.

2. CNC-Cut Battery Hold Downs

• Precision Fit: These are meticulously crafted using CNC technology to match specific vehicle models.
• Ease of Installation: Typically, they are easy to install with basic tools, ensuring your battery is securely fastened in no time.

3. Universal Battery Tie Downs

• Adjustability: Designed to fit a broad range of battery sizes, these are ideal if you frequently switch batteries.
• Versatility: Often, they include adjustable clamps, making them a flexible and economical choice.

4. Heavy-Duty Battery Straps

• Material: Usually made from high-strength materials like nylon or rubber.
• Simplicity: Quick to install and adjust, these straps provide a simple, yet effective solution to keep the battery stable.

5. OEM Replacement Holders

• Compatibility: Directly replace the factory default holders to ensure a perfect fit.
• Reliability: Designed to the vehicle’s original specifications, providing peace of mind.

Making the Right Choice

When selecting a battery securing option, consider factors such as the type of terrain you’ll be navigating, the battery size, and any additional features you might need. A secure battery not only prolongs its life but also enhances the overall safety and performance of your Jeep.

What features does the Manta Ray Rear Bumper offer for a Jeep Comanche MJ?

Discover the Manta Ray Rear Bumper for Jeep Comanche MJ (1986-1992)

What Makes This Bumper Stand Out?

Transform your Jeep Comanche MJ with this robust and versatile addition. The Manta Ray Rear Bumper is more than just a protective accessory; it’s a blend of strength and practical design.

Key Features

• Unmatched Durability: Crafted from high-quality materials, this rear bumper ensures longevity and can withstand the toughest conditions.
• Enhanced Functionality: Designed to improve your off-road experience, it offers essential features like integrated recovery points and improved departure angles.
• Stylish and Functional Design: Its sleek look complements the rugged aesthetics of your Jeep, while the design ensures optimal performance without compromising style.
• Easy Installation: Comes with all necessary hardware for a straightforward installation process, allowing you to upgrade your vehicle hassle-free.

Elevate your Jeep Comanche MJ with a rear bumper that delivers on all fronts. Improve both appearance and performance with this essential upgrade.

How can the Driver Side Battery Tray Mount Adapter enhance a Jeep Cherokee XJ or Comanche MJ?

How the Driver Side Battery Tray Mount Adapter Enhances Your Jeep Cherokee XJ or Comanche MJ

Elevate the capabilities of your Jeep Cherokee XJ or Comanche MJ with a high-quality Driver Side Battery Tray Mount Adapter. Here’s how it transforms your ride:

• Seamless Integration: This adapter is engineered to fit perfectly on the driver side, ensuring seamless integration with a universal battery tray. This precision fit minimizes the risk of vibrations and battery movement during off-road adventures.
• Optimized Space Usage: By efficiently utilizing the available space in your engine bay, this adapter allows for easier access and organization. It provides an ideal platform for additional enhancements like a dual battery setup, which is crucial for those who rely heavily on accessories during expeditions or off-grid travel.
• Durability and Stability: Constructed from robust materials, the mount adaptor is resilient against the rigors of rugged terrains. Its stable design ensures that your battery remains securely fastened, reducing wear from shifting and extending battery life.
• Enhanced Performance Upgrades: The adapter enables the installation of larger or more powerful batteries to meet the demands of enhanced electronics or auxiliary power systems, thereby boosting your vehicle’s overall performance and reliability.

Upgrade your Jeep Cherokee XJ or Comanche MJ with a Driver Side Battery Tray Mount Adapter for a more organized, efficient, and reliable off-road experience. Enjoy the enhanced functionality, durability, and performance it brings to your adventure-ready vehicle.

How can I enhance the steering capabilities of my Jeep for better off-road performance?

Bankston built a custom belly pan, to which he attached a pair of TNT Customs Y-link control arms and 9-inch lift coils, which were compressed down to a 4.5-inch lift by the weight of the diesel. Bilstein 5150 shocks were used with a custom track bar and a 1-ton GM steering system, ZJ pitman arm and a custom steering box brace for the Dodge Durango steering box.

To truly transform your Jeep’s off-road capabilities, consider upgrading your steering system. A well-engineered steering kit can significantly enhance your control on rugged terrains, providing the precision and reliability needed for intense off-road adventures.

Enhancing Steering with Custom Solutions

For those looking to customize, incorporating high-quality components like the TNT Customs Y-link control armsand Bilstein 5150 shocks can make a substantial difference. These parts not only improve suspension but also contribute to a more responsive steering experience.

• Custom Track Bar: This component aids in stabilizing your vehicle’s handling, ensuring a smoother ride over uneven grounds.
• 1-Ton GM Steering System: Known for its durability, this system is a solid base for those seeking robust steering performance.
• ZJ Pitman Arm: Enhances the steering linkage, allowing for better maneuverability.
• Custom Steering Box Brace: Provides added support, particularly useful when using a Dodge Durangosteering box.

These modifications create a synergy that optimizes your Jeep’s steering, making it ready to tackle any off-road challenge. Whether you choose a pre-packaged kit or a custom setup like Bankston’s, upgrading your steering is a crucial step towards achieving superior off-road performance.

What is the price of this upgrade?

The upgrade is priced at $419.93, offering a competitive value for the performance improvements it delivers.

What are the benefits of using this product?

The product promises enhanced precision and confidence in steering, elevating your overall off-road experience.

What Jeep models are compatible with this upgrade?

The steering kit is compatible with Jeep models such as the Cherokee XJ, Comanche MJ, Wrangler TJ, and Grand Cherokee ZJ, covering years from 1984 to 2006.

What product can I use to enhance my Jeep’s steering capabilities?

You can use the High Clearance Steering Kit to enhance your Jeep’s steering capabilities for improved performance, especially off-road.

How can I convert my Jeep Cherokee or Comanche to use all electric fans?

The exhaust system is 3-inch mandrel bent from the turbo back with no muffler. Bankston bought several tailpipes for 1998-up Dodge ¾-ton vans at $20 each. This gave him all the bends and straight sections he needed to cut, weld, and fabricate his exhaust system. To keep the Comanche Cummins cool, Bankston used a three-core HD cooling aftermarket radiator in the original mounts with a set of triple 9-inch electric fans. Bankston reports the engine runs cool as a cucumber in all conditions.

For those looking to convert their Jeep Cherokee or Comanche to all-electric fans, a laser-cut aluminum fan shroud is an efficient and reliable solution. Here’s how you can make the upgrade:

• Select Your Fans: Choose three 10″ electric fans that fit your performance needs. These will provide the airflow required to keep your engine cool.
• Installation: Mount the fan shroud, which is designed to work seamlessly with your chosen fans. This setup ensures optimal cooling efficiency and a snug fit, preventing overheating even in demanding conditions.

With these components, you’ll enhance your vehicle’s cooling system, much like Bankston did, ensuring that your Jeep runs smoothly under any circumstance. This simple upgrade can make a significant difference in performance, especially for those who push their vehicles to the limit.

Is there a straightforward solution available for converting to all electric fans?

Yes, the use of a laser-cut shroud provides a tailored solution for this conversion task.

What size and how many fans are needed for the conversion?

The conversion requires three fans, each measuring 10 inches in diameter.

What product can facilitate the conversion to electric fans in a Jeep Cherokee or Comanche?

A specially designed aluminum shroud is available to assist with the transition to electric fans in these vehicles.