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Answers to all your Jeep questions

Posted in How To: Tech Qa on September 6, 2017
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Dauntless Search

Where can I find a complete 225ci odd-fire V-6 engine for my ’51 CJ-3A project?

@skinny_fabrication
Via Instagram @cappaworks

Unfortunately, the complete engine you are trying to locate has not been produced in more than 50 years. You can’t exactly go out and buy a brand-new vintage crate engine. If you did find one, it would likely be too valuable to pull out of the box and use in your Jeep.

Anyway, the Buick-sourced 225ci odd-fire Dauntless V-6 came in the ’66-’71 Jeepster Commando, CJ-5, and CJ-6, as well as several different ’64-’67 Buick cars. It’s essentially a small-block Buick V-8 that has been relieved of two of its cylinders, providing the odd firing order. The Dauntless V-6 produces an incredible amount of torque, so it was a coveted Jeep engine swap when the engines were more plentiful. The hefty Jeep 225 flywheel is significantly heavier than the Buick car version, which is said to have been done to reduce the vibrations caused by the odd-fire ignition. The heavy flywheel also helps maintain engine rpm when chugging down the trail.

Locating a complete engine will take a little bit of searching and tenacity. You can start your search on craigslist.com and ebay.com. They regularly show up here for $500-$1,000. Other places to check back regularly are willystech.com, earlycj5.com, and facebook.com/dauntlessv6. Of course, many of these used engines will be in need of a full rebuild, which may make it a less cost-effective option than swapping in a more modern fuel-injected powerplant like a GM 4.3L.

If you can locate all of the tins, accessory group, and other external bits, remanufactured long blocks are available from many different companies such as BJ’s Off-Road (bjsoffroad.com).

Aftermarket performance parts, while limited, are still available for the old Dauntless V-6. Isky Racing Cams (iskycams.com) offers several internal power parts and Offenhauser (offenhauser.co) has an intake manifold.

Full-Flow 4.0L

Is there really a use for a high-flow water pump on a stock Jeep 4.0L inline-six cooling system?

@liamlikeneeson
Via Instagram @cappaworks

The overall cooling capacity and cooling requirements of an engine are dependent on many factors, including driving style. An aftermarket high-flow water pump is probably not necessary on a completely stock 4.0L Jeep that is driven well within the manufacturer’s intended use. However, when you start adding more load to the engine or block airflow to the radiator, you could very easily surpass the cooling capacity of even a stock 4.0L. Extra load on the engine that could cause it to run warmer comes in many forms. The addition of larger tires increases rolling and wind resistance. Added weight in the form of a larger spare tire, aftermarket bumpers, body armor, and so on also increase the load on the engine. Add in towing a small trailer, a steep grade, turning the A/C on, and brutal triple-digit desert temperatures, and you could be beyond the limits of the factory 4.0L cooling system.

Aggressive driving in extreme off-road conditions like deep snow, mud, and sand can also tax the factory cooling system beyond its capabilities. Also, a winch or off-road lights mounted to the front bumper could block airflow to the radiator and exacerbate the problem enough to require cooling improvements that may or may not include a high-flow water pump from a company such as FlowKooler (flowkoolerwaterpumps.com).

Of course adding a supercharger, turbo, or other power adder that significantly increases engine output will also cause the engine to create more heat than stock. A larger radiator, a more efficient fan, and proper radiator shrouding along with a high-flow water pump can all be utilized to keep a higher horsepower engine cool.

Best 4:1 TJ Mod

What is the best way to add 4:1 low range transfer case gearing to a ’98 TJ with a 4.0L engine and an NV3550 manual transmission?

@jkjackinney
Via Instagram @cappaworks

There are several ways to add 4:1 low range gearing to the short wheelbase Jeep TJ. However, not all of them are practical. The biggest concern will be rear driveshaft length, especially if your Jeep is lifted or if it has a high-clearance belly pan installed on it.

The NV3550 must have been swapped into your Jeep. It was not available until the ’00 model year. The ’89-’99 Jeep Wranglers with a manual transmission and a 4.0L would have come with the AX15. The NV3550 ran through the ’04 model year. Fortunately, if your Jeep does indeed have the NV3550, it opens up other transfer case gearing options.

The most expensive, complex, and also the most durable way to increase transfer case gear reduction is to swap out the factory NV231 transfer case in your Jeep and install an Advance Adapters (advanceadapters.com) two-speed Atlas transfer case. There isn’t a 4:1 low range gearing option, but there are many others to choose from including 5.0:1, 4.3:1, 3.8:1, 3.0:1, and 2.0:1. Aside from the lower gearing, the Atlas transfer case has other off-road–worthy features such as the ability to utilize two-wheel drive low range when making your way around tight technical corners. You can also shift the Atlas into front-wheel drive only for more extreme cornering, if your front axle is up to the task.

The most practical option is to simply locate and swap in a stock ’03-’04 NV241OR Rubicon Rock-Trac 4:1 transfer case. However, this option will require that you convert your speedometer over to an electronic unit. Your stock NV231 has a traditional speedometer gear. The NV241OR has an electronic speedometer sending unit and no provision for a traditional speedometer gear. One way to remedy this problem is to install an electric speedometer drive kit from Novak Conversions (novak-adapt.com). The kit converts the electronic signal and spins the analog speedometer cable at the correct speed. With this kit you can retain your factory mechanical speedometer and cable.

The easiest and least expensive way would have been to install 4:1 low range gearing into your NV231 transfer case. Unfortunately, TeraFlex (teraflex.com) no longer offers the NV231 TeraLow 4:1 kit. Although, it may be possible to find a used kit or a new kit that has been hidden away somewhere on a dusty shelf.

Adding a crawl box between your NV3550 and NV231 with an additional 2.72:1 low range, such as the NorthWest Fabworks (northwestfab.com) Black Box Underdrive would provide a lot of different gearing options. This combination of multiple available low range ratios would make your Jeep more versatile than simply having one 4:1 low range gear. Unfortunately, it is not a very practical option. The limited TJ wheelbase combined with the crawl box causes the rear driveshaft to be too short and angled too steep for most applications.

EFI Quandary

Is a factory EFI system better than a TBI for a 4.0L? It’s a daily driver so fuel economy is important, but it’s also a weekend warrior. My 4.0L actually has the AMC 258 inline-six intake manifold with a carburetor, but I also have the original manifold without the EFI gizmos. I was planning to source all of the stock EFI components or a TBI from the wrecking yard. What are your thoughts?

@danielpineda06
Via Instagram @cappaworks

Generally, you won’t see a significant difference in performance or fuel economy between a properly working TBI and a proper functioning MPI fuel system. Having said that, the factory Jeep 4.0L MPI fuel injection system is well designed and has many features that work together to make it reliable and efficient. A garage-assembled TBI system atop an AMC 258 intake will likely not perform as well as the factory 4.0L EFI. I would recommend acquiring all of the factory 4.0L EFI components and then invest in a stand-alone engine wiring harness. A simple 4.0L EFI engine wiring harness is available from several different companies including Hesco (hesco.us) and Painless Performance (painlessperformance.com). However, they are for specific 4.0L model years. Hotwire Auto (hotwireauto.com) can pare down a wrecking yard harness to fit your application, but you will need to supply a factory engine wiring harness for the company to start with.

If you decide to keep the AMC 258 intake and don’t want to mess with collecting random 4.0L EFI parts from the wrecking yard, you could simply install a complete Howell (howellefi.com) throttle-body fuel injection kit. It includes a GM throttle body and computer that have been designed and programed to fit the AMC 258 intake.

Four-Link in a Box

Can you help guide me in building a four-link coil-spring suspension on a CJ-3B?
I want to extend the original 80-inch wheelbase to 91-95 inches. I’d like to install four-link suspensions at both the front and rear. The chassis is the original Mahindra CJ-3B.

@rc9192
Via Instagram @cappaworks

There are a lot of variables to consider when building your own custom four-link suspension under a Jeep. I think you should start with reinforcing the frame. I’ve never actually seen a Mahindra CJ-3B in person, so I can only assume the frames are similar to the other late model U.S.-made flatfender Jeeps. Consider boxing the entire frame, or at the very least reinforce the front and rear portions of the frame, especially around the steering box. Another way to reinforce the frame is to install a well-thought-out, bumper-to-bumper rollcage that ties into the chassis in at least six places, preferably eight.

Extending the wheelbase out to the mid 90-inch range could open up a Pandora’s box of other problems, depending on the planned ride height of the Jeep, engine selection and location, fuel tank location, and so on. Obviously, you will need to cut and modify the body metal, but if you want to build a low-slung Jeep with a low center of gravity you may need to chop off the rearmost portion of the frame, and maybe some of the front too. These sections would need to be rebuilt to make room for the axle to come up as the suspension compresses. If you plan to lift it to the moon, the frame should not be in the way of the axles.

To simplify your custom suspension build, you might consider starting with a three- or four-link kit from Ruff Stuff Specialties (ruffstuffspecialties.com). These kits remove a lot of the guesswork when assembling a proper three- or four-link coil-sprung or coilover suspension. The included brackets will make locating the suspension mounting points much easier.

Wiring Wondering

I have a bunch of questions about the Garage Project GPW, but I'd like I start with the wiring harness. What did this harness run? Can you give me some details on it? Are you running a TBI?

@jwilson_55
Via Instagram @cappaworks

At this very moment, I’m working my way through the wiring on the Garage Project GPW. The chassis wiring harness has been all built by me, one wire at a time. There aren’t that many wires so I just figured it would be easier, cleaner, and less complex than using an off-the-shelf chassis wiring harness. The front and rear half of the Jeep is wired. Most of the wires are currently poking out of the dash waiting to be terminated at a switch or gauge.

The brand-new GM 4.3L Vortec V-6 engine I started with was still in a crate when I got it. As best I can tell, it was destined for an ’02 GM van. It features the factory multi-point fuel injection. Team 208 Motorsports (team208motorsports.com) built the engine wiring harness and programmed the ECM. The company specializes in engine wiring harnesses, engine computers, and custom tuning. The harness prices vary depending on a multitude of options. My engine wiring harness and computer are designed to be very simple and minimalistic. Team 208 Motorsports deleted many of the sensors and will tune the engine via speed density. Your best bet is to get ahold of Team 208 Motorsports to get a price on exactly what you need for your engine swap.

Stinky Jeep

I have an ’00 four-cylinder TJ with an automatic transmission. It sat for a month while I performed some repairs. I finally drove it, but when I get on the throttle there is a bad ammonia smell coming from someplace. It does not have an air conditioning system. It smells just like it would if you opened a bottle of ammonia and sniffed it. It’s definitely not the common sulfur or rotten egg smell that sometimes emits from an exhaust. I have smelled those before. The Jeep has 175,000 miles on it. Also, the fuel in the gas tank is about two months old.

@stevesmithbadhabitt_jeeps
Via Instagram @cappaworks

Ammonia is for sure an odd smell. There are a few things it could be, but the most likely culprit is the catalytic converter. In most cases the catalytic converter will emit a sulfur or rotten egg smell as you have noted, but it’s not impossible for an ammonia smell to come from the exhaust. It’s difficult to get 175,000 miles out of a catalytic converter. I suspect it’s on its way out. There are other possibilities too. It could be that something crawled up and into your Jeep and died on the exhaust or transmission. Washer fluid has an ammonia smell too. A leak in the tank or hoses could be wafting the scent through the vents and into the cab, but it’s pretty unlikely. Changing the catalytic converter is probably a good place to start after you take a look around for dead things and leaky washer fluid.

Battling Brake Noise

I have a ’15 two-door JK with a rear brake problem. When I put it in park and then put it in reverse or drive the rear brakes moan and groan as you let up on the brake pedal. It also does this at stop signs when moving ahead behind someone. I have taken it to the Jeep dealer and they have cleaned the slides and lubricated them. The noise stops for about 10 minutes and then returns again. I took the Jeep back and they said I needed to replace the rear pads even though they are like new. I have two other friends that have the same noise in their rear JK brakes. Have you ever heard about this before and what can we do to fix it, before we buy new pads?

Also, just a warning for other readers, I bought this Jeep in July 2016 with 10,000 miles on it from a used car dealership near Rochester, New York. When I took the Jeep to a dealer in Pennsylvania, I was told I don't have a warranty because it came across the border of Canada. I called the used car dealer about this and I was told I should have known about this. I called Jeep USA and Jeep Canada and they said that’s the way it is, even though the Jeep was built in Ohio. The used car dealer finally gave me a generic warranty. It’s better than nothing, but it doesn't cover brakes. I just wanted to let others know about the border thing. Any help with the brake noise would be appreciated.

Gail Wendel
Via email

Even though brake noise can be maddening, it is fairly common on 4x4s, especially 4x4s that spend their time in mud, sand, dust, or on salted or graveled winter roads. These types of environments typically cause the brakes to develop squeaks and grinding noises. The squeaks can usually be chased away with the use of an anti-squeal on the backsides of the brake pads. Grinding noises are typically caused by sand or small rocks embedding themselves into the brake lining and grinding on the rotors. Unfortunately, I don’t think either of these is your problem. The brake groaning is really common on the Jeep JK rear brakes. I think it’s more to do with the interface between the pads and the rotors. The only real way to try and eliminate it would be to try a different brand of brake pad. You could try EBC Brakes (ebcbrakes.com) Truck Yellowstuff Sport pads or EBC Extra Duty Truck/SUV & Jeep pads. Either of these should eliminate the noise and improve braking performance. If you want to improve braking performance all around, consider swapping to EBC pads and slotted rotors at all four corners.

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