Short Block vs. Long Block vs. Crate Engines

Car Engine, Isolated on White
B&M Noskowski / Getty Images

The engine in a typical car should last a few hundred thousand miles, and some have hit even a million miles, depending on maintenance. However, manufacturing inconsistencies, lack of maintenance, or other circumstances can dramatically shorten the life of an engine, sometimes in spectacular ways. If you need to replace a damaged engine or upgrade your engine, you have a few choices to make. Short block vs. long block vs. crate engines—which should you choose?

engine disassembled
Not everyone has the time and tools required to fully rebuild or assemble an engine. Malkovstock / Getty Images

The basic difference between a short block vs. long block vs. crate engines is their level of assembly. Of course, you could build your own engine, piece by piece, if you have the tools and knowledge or have a friend with a machine shop. If you’re building a race car, that’s a good way to go, but you wouldn’t likely build an engine from scratch for your daily driver. To shorten your vehicle’s downtime and reduce the level of complexity, you might choose a crate engine, long block, or short block.

Basic Differences

At its most basic, the difference between short block, long block, and crate engines is that each is progressively more expensive but requires less time and expertise to install. We’ll cover some of these differences and similarities, as well as instances when you might choose one over the other.

mechanics rebuilding engine
Depending on tools, expertise, and budget, you may spend more or less time rebuilding your engine. MS Phil Speck / USANG

Short Block Engine

A short block engine is essentially just the engine block with a few major components. A short block engine usually includes, preinstalled, a new crankshaft with bearings and caps, new connecting rods, and new pistons. When installing a short block, you’ll need a master gasket kit so you can transfer parts from your old engine to the new short block, such as cylinder heads, oil pump, oil pan, timing sprockets and pulleys, timing belt or chain, camshafts, and intake and exhaust manifolds, as well as sensors and actuators. Choose a short block if the bottom end is damaged but the top end (cylinder heads) is in good condition and you have the time to swap over all the parts.

Long Block Engine

Depending on who makes it, the long block usually includes the short block with the cylinder heads preinstalled, most likely including timing components and anything behind them, such as the oil pump and camshafts. When installing a long block, you’ll need to transfer some parts from your old engine, such as the intake and exhaust manifolds, and some of the sensors and actuators. Choose a long block engine if there’s damage in the bottom and top end.

Crate Engine

Depending on who makes it, crate engines can range from long block to complete, including the oil pan, cylinder heads, intake and exhaust manifolds, sensors and actuators, maybe even the engine main harness. We’re referring to a complete engine, which is a good idea for those looking for a drop-in solution to their engine problems. No parts are transferred to the new engine, aside from the alternator, air-conditioning compressor, and engine mounts, which significantly reduces the time to install. Choose a crate engine or complete engine when time is of the essence or the engine has suffered extensive failures. Crate engines can also be custom-ordered, the weapon of choice for many enthusiasts who want more power from their custom cars.

These are the three main categories of new engines you can buy for the typical project, but not the only ones. You might also consider used junkyard engines or remanufactured engines.

Junkyard Engine

junkyard cars and engines
A junkyard engine might be a good choice for your vehicle project. Julien Grosjean / Getty Images

A junkyard engine might be a good choice if you are looking to save money. These usually come complete, hopefully with intact wiring, though each facility does things differently. If you have an engine-savvy friend, they can help you inspect the engine before you buy it. You-pick junkyards will require that you remove the engine yourself, so you can take as much care as you want to save the parts you need the most. Choose a junkyard engine if budget is of primary concern, but be aware that it might not come with any warranty and might have already been abused or neglected.

Remanufactured Engine

These used engines may be available in differing levels of assembly, from short block to long block or complete. The difference between a remanufactured or rebuilt engine is that they’ve been overhauled or at least certified by engine experts. They’re used and may have varying levels of new parts, are usually more expensive than junkyard engines but less expensive than crate engines, and usually come with a warranty. Choose a remanufactured engine if you’re not planning on rebuilding it yourself.

car engine on engine stand
Here, an engine is either ready for disassembly or reinstallation. PIXNIO

Choosing between these different engines if you must replace or rebuild an engine needn’t be overwhelming. Considering your expertise, available tools, and budget, not to mention existing damage, choose the engine that best meets your needs. Still wondering which is best? Ask an engine-savvy friend or a trusted mechanic.