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Jeep Engine Swap Pitfalls, Conundrums, and Glory

An engine swap is a big project. Only the truly dedicated or certifiably insane would even think to try it, but if you’re determined to put wrenches to work on your rig, we’re here to help.

Before you go ripping out your OEM equipment, consider the following advice we’ve compiled from those who have been there and done that:

Start by Picking A Good Engine

The engine you select should be suitable for the application. Here are some popular power plants others have tried with mediocre results:

  • Dodge V10 – The big sexy Viper motor sounds fantastic, but underdelivers for the all the fuss.
  • Ford 4.6 V8 – These cheap plentiful engines enjoy lots of aftermarket support.
  • Cummins 5.9 Diesel – It delivers super low-end torque, but it already weighs half a ton.
  • Cadillac North Star V8 – These faulty aluminum V8s are prone to overheat and underwhelm.

If you are looking for a gasoline-powered V8, the 5.3 Liter GM Vortec engine out of an older Silverado is your best bet. For a full diesel Jeep Cummins swap, focus on the 3.9 Liter B4T engine. Both options are often regarded as part of the top 10 best Jeep engine swaps. They produce good power profiles and have even weight distribution.

Get Ready to Make It Fit

You will undoubtedly need new motor mounts, but you may also have to modify your engine compartment. If you’ve got a long block that has overhead cams or a higher intake manifold system, you might have to cut into your fender wells and firewall.

On a Jeep Wrangler diesel conversion, you need space for extra ducting and intercooler systems. The turbochargers in these engine designs require larger intake, and you need to plan for the cooling fan and shroud.

Consider the Whole Drivetrain

A new bell housing or adaptor plate makes short work of mating the gearbox to the block, but you’ve got other problems to solve. Your gears and drivelines were engineered to withstand a certain amount of input torque. Overspin bends and shatters metal.

You might be better off just swapping the transmission too. At the very least, upgrade U-joints, axles, and gears accordingly.

Finding All of Those Auxiliary Components

Crate motors usually lack the accessories you need to run the engine. Your manifolds, generator, control modules, and wiring harnesses are all sold separately.

There are exceptions. A complete engine swap kit might provide everything you need. You can also purchase a wrecked donor vehicle and scavenge the other components. Locating these deals can be tricky, but always source your supplies before you start.

Off-Roading in Your Newly Powered Rig

Gravity and physics don’t change, even when your vehicle weight and power output do. If your Jeep TJ engine swap project has burdened your stock suspension with a massive cast iron block, you’re going to notice unpleasant changes to your handling.

Poor balance and excess weight cause your Jeep to flip easier or sink lower in the mud or sand. Compensate with upgraded suspension systems. Heavier springs and sturdier shocks keep the load under control when you hit the trails.

Parts Solutions for You

At 4WD.com we’ve got the most extensive inventory of aftermarket and OEM Jeep components. If you’ve made modifications to your vehicle, we can help you find the unique fit of bits and pieces to keep it all working together. Browse our inventory and ask us about items you need help locating.