How Much HP Does A Cummins 4BT Have, And How Much Does The Crate Engine Cost?

If you're searching for information about the Cummins 4BT diesel engine and how it differs from the 6BT, you likely fall into one of three camps. Camp one enjoys reading about obscure diesel engines. Camp two discovered the Cummins 4BT diesel by coming into the possession of a vehicle with one under the hood. Camp three is looking to power an off-road vehicle, with enough torque to crawl over rough terrain at low speeds (the 4BT is a great engine to put in a Jeep Wrangler).

Cummins 4BT diesel engines built prior to 1998 made 105 hp and 265 lb-ft of torque. Those made after 1998 are known as 4BTA Cummins engines. Thanks to upgrades present in the 4BTA, horsepower ratings for the newer engines jumped to 170 and torque values climbed to 420 lb-ft. While those are the standard ratings for the four-cylinder Cummins 4BT and 4BTA, some variations are found among providers.

There are multiple outlets for Cummins 4BT crate engines. Cummins offers reconditioned 4BT diesel engines (remanufactured at the Cummins ReCon Engine Plant located in San Luis Potosi, Mexico) for marine use. The Cummins ReCon 4BT is rated at 150 or 155 hp depending on whether it's built for commercial and government or recreational applications. 

Trans Atlantic Diesels also sells the 150- and 155-hp Cummins ReCon 4BT diesel engines for marine use with complete crate engine packages priced at $28,500 per a quick email correspondence with the company's office manager. Using this engine on public streets may require some extra work depending on where you operate it since the product description cautions against installing the engine in boats built after 1999. The ReCon 4BT comes with a two-year 2,000-hour warranty backed by Cummins.

Alternatively, CPP Diesel sells a new complete 4BT crate engine for $9,179 including fuel lines, injectors, harmonic damper, exhaust manifold, turbocharger, and your choice of inline or rotary fuel pump. In addition, Dale's Superstore lists a similarly equipped Cummins 4BT crate engine (minus the H1C turbo listed separately for $499) priced at $7,970.

In a rock crawling off-road vehicle, engine torque is paramount. So, compared to the popular 4.0L inline six cylinder that came standard in a wide array of Jeeps during the late 1990s and early 2000s, the 3.9L Cummins 4BT stands out. The 4.0L Jeep engine is rated at 235 lb-ft of torque, 30 lb-ft less torque than the 4BT. However, the 4.0L inline-six makes a lot more horsepower, rated at 190 compared to the 4BT's 105.

Cummins introduced the 105-hp 4BT (4-cylinder, B-series, Turbocharged) in 1983. The original design, closely related to the legendary 5.9L 6BT Cummins, featured two valves (intake and exhaust) for each of its four inline-cylinders. The upgraded 170-hp 4BTA diesel engine that came out in 1998 with four-valves-per-cylinder could be a better choice if more power is required.

The biggest advantage to using a 4BT Cummins, over the standard 4.0L gas engine, in a rock crawler is the peak torque delivery occurring at around 1,600 rpm compared to the 3,000 rpm peak torque of the 4.0L. The downside of the 4BT for offroad use is its nearly 800-pound operating weight.