What’s the difference between long and short blocks?
When you’re shopping for a crate engine, it’s important that you understand the terminology.
What’s the difference between a long block a short block engine? Yeah, that may seem like a simple question to many of us, but to someone new to the game, and shopping for that shiny crate engine, it can get a bit perplexing. There are three basic configurations: short block, long block, and deluxe (or complete). As expected, each level is more expensive than the previous. Which way you go is a math equation based on your skill level, the thickness of your wallet, and how much time you’re willing to invest in the project.
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Knowing the difference between a long block and a short block is the first step in buying that new engine for your hot rod.
What’s Included in a Short Block?
When buying a crate engine, the smallest configuration is a short block. Many people like going this route since the short block is the toughest to do yourself if you are a novice at building an engine. It typically consists of the block, crankshaft, rods, and pistons. All machined, balanced, and assembled with the rings gapped and ready to rock. It could include a camshaft and timing gear, but that varies based on the manufacturer. By going this route you can pick the parts needed for your particular circumstances. Some would say the biggest difference between a short block and a long block is cash. We would say it’s also convenience.
What’s Included in a Long Block?
What is in a long block can vary depending on where you buy it, but the minimum parts installed in a long block package would be the block, crankshaft, rods, pistons, heads, and usually the camshaft and valvetrain. So, everything in the short block plus at least heads and usually the valvetrain including the timing chain. Sometimes you get a timing cover, valve covers, balancer/damper, and oil pan, but oftentimes not. This is a great option for someone who knows engines but has little to no experience building one. With a long block, all the hard work is done and the buyer only has to be concerned with choosing the right accessories and getting the engine installed in their car.
What Is a Deluxe Long Block?
There are also deluxe long blocks that include everything including the carburetor, intake, distributor, oil pan, and even the spark plugs and wires. Buying an engine like this, in theory, saves you some cash over going a la carte, but you need to do the math to see if you could do it cheaper on your own. But what it does save you is time, and going this route nets you the parts the engine builder feels are right for the crate engine combination. They would typically not include car-specific items such as headers, but factory crate engines, such as LS mills from GM, do include exhaust manifolds and a water pump along with most of the sensors. Usually there’s an oil pan, but it may or may not work with the car you plan on dropping the engine into.
Is It cheaper to Rebuild or Replace an Engine?
If you’re doing the work yourself, then typically it would be cheaper to rebuild an engine rather than replace it. If you’re having it rebuilt, and assuming all the parts are in good shape, it still might be cheaper to have the engine rebuilt rather than buying new. However, this somewhat depends on what’s wrong with the engine you’re rebuilding. If it turns out your block is cracked, or you spun a rod bearing, then parts and machine work costs can quickly pile up. It can also take time, and as they say, time is money. This is one reason why short block cores are so popular. Just swap over all the parts from your original engine to the short block, and you can be back on the road much faster than going the rebuild route.
What Does Bare Block Mean?
Well, just like the sign says. A bare block is a block without any rotating parts. In some cases, like a new GM block, it will include cam bearings already in place, but everything else, such as head dowels, block plugs, and sensors, need to be added to the mix. Also, in many cases the cylinders will need to be bored or honed out to match your pistons.
What Is a Rotating Assembly?
The rotating assembly, or kit, always consists of the crank, rods, and pistons. Or, in layman’s terms, all the spinny bits except for the camshaft. The assembly, for a charge, can come fully balanced and sometimes will include the rod and main bearings. Buying a rotating kit is easier than buying the individual parts since you’re guaranteed they are all designed to work together. Obviously, kits consisting of cast parts will be less expensive than one with forged parts.
Key Differences Between Long and Short Blocks
- Short blocks include, and fully assembled, the block, crank, rods, and pistons.
- Short blocks may include other items such as the camshaft, timing chain, and covers.
- Long blocks are short blocks with the heads and typically the valvetrain installed.
- Deluxe long blocks will also include the intake manifold, oil pan, carburetor (or throttle body), distributor (or coil packs), and covers for the timing chain, valves, and an oil pan.
- Bare blocks are exactly what the name implies: a bare iron or aluminum block that may need machine work before being built into an engine.
- Rotating assemblies consist of the crank, rods, and pistons and may come balanced along with the necessary bearings.
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