Replacing an engine takes a lot of work, but if you drive a vehicle long enough, it's an inevitability. In this article, we’re going to help you answer questions like, “When should you consider using a new engine instead of rebuilding the existing motor?” and “Why should you consider a crate motor for your classic car?”
When Should I Replace My Engine?
Practically any engine damage can be repaired with new or machined parts. However, it doesn't take long for the cost of these repairs to exceed the value of the engine. Even if a repair is affordable, you're still left with a used motor that is susceptible to future problems. There are four failures that lead to most engine replacements:
-The timing belt or chain broke, allowing the valves and pistons to come in contact with each other. This can cause catastrophic damage, breaking valves, scarring the cylinder walls and denting or even breaking pistons.
-A coolant system failure caused the engine to overheat, causing parts to warp and seize inside the block.
-A lubrication system failure left internal components dry, allowing metal to metal contact. This rapidly wears down surfaces, ruining moving components inside the motor as well as bearing, cylinder and combustion chamber surfaces.
-The head gasket failed. This gasket seals the head and block together, as well as the passage inside that allow oil and coolant to pass between these two components. In extreme cases, hydrolocking can occur if too much coolant enters the cylinder, blowing the motor apart.
What is a Crate Engine?
While other companies have moved on from their classic muscle car engines, Chevrolet has continued to develop their small block V8, adding advanced features like variable valve timing and direct injection while keeping the OHV's compact design. This allows it to deliver world class performance in a small, light package. Likewise, the classic big block V8 was used in production trucks as recently as 2009 and remains popular for performance applications.
These engines have been in GM products dating back to the mid-50s, and they've been used by hot rodders and race car builders for decades. With such a strong following, it seems logical for GM to offer off-the-shelf engines using modern technology and quality control that are still compatible with the parts and cars built around this family of engines. These are known as “crate” engines because they come in a crate, fully assembled. Although this name can be applied to any engine in a box, it's mostly used for performance motors.
Chevrolet Performance manufactures several engines based on the small block and big block designs, letting buyers pick the right balance of performance, features and price to fit their needs. These offerings range from the classically-styled 290 Deluxe to the drag racing-focused LSX454R that produces 776 hp. Chevy has also recently added the turbocharged four cylinder LTG to their lineup for builds where space is at a premium. Whether you're looking to show off at shows like Musclepalooza or the Tri Five show or you just want to repower your classic Texas-size truck, a crate engine provides a level of quality you can't get from rebuilding an old motor.
What's Included with an Engine?
GM sells their OEM engines as long blocks with oil pans. This means the heads and bottom end are fitted to the block and all internal components are in place, but it will still need accessories, an intake, exhaust manifolds, electrical components and fuel components to work. Since an OEM engine is identical to the engine installed when your vehicle was built, you can reuse any parts already in your vehicle that are still in good condition.
The equipment included on performance crate engines depends on how they're packaged. “Turn-key” engines include the air cleaner and ignition system. “Connect & Cruise” packages also include a transmission and any electronics needed to run the motor. Other crate engines may have a complete intake, just the intake manifold, or no intake at all, and they may or may not include an ignition system. Exhaust manifolds are never included, and some accessories may be left off since there isn't a good one-size-fits-all solution for every application.
What Do I Need to Use a Crate Motor?
Assuming your vehicle already has the right engine mounts and the transmission is fitted with the correct bellhousing, you'll also need exhaust manifolds or headers that will fit in the space inside your vehicle. Some accessories may need different brackets, while going from carburetors to fuel injectors will require the use of a high pressure fuel pump and matching fuel lines. If the engine you're installing makes a lot more power than the previous power plant, care should be taken to make sure the drivetrain can handle it.
What Other Repairs Should Be Made When Replacing an Engine?
In most cases, both the engine and transmission will need to be removed. This makes it a great time to replace the clutch and flywheel if you have a manual. Engine and transmission mounts are also easy to replace, and new seals will be needed when attaching parts like the manifold.
How Do I Replace the Engine in My Vehicle?
This is an involved process requiring plenty of space and some specialty equipment, so it may be worth having this done by a shop instead of doing it all yourself. Here's the basic process:
1. Drain the coolant system and the oil from the old engine.
2. Remove all wiring connectors and hoses from the engine.
3. Unbolt the intake, exhaust and air conditioner compressor. On some engines, it may be easier to discharge the A/C system and detach the hoses from the compressor.
4. Check the engine compartment and remove any other parts that may get in the way, including the hood, fan shroud and radiator. On some vehicles, it may be possible to remove most of the front clip.
5. Disconnect any driveshafts or axles connected to the transmission.
6. Attach an engine hoist to the engine and raise the boom until the chains connecting the engine to the hoist are almost tight.
7. Unbolt the engine and transmission mounts.
8. Lift the engine and transmission out of the vehicle as one unit. While it is sometimes possible to unbolt the engine and lift it out by itself, the bolts are usually difficult to reach and the length of the transmission's input shaft may not allow enough space for the engine to separate from the transmission while inside the engine compartment.
9. Lower the engine and transmission onto a safe, stable platform. Separate the engine and transmission, then remove any parts that will be reused, like the exhaust manifolds. Bolt these onto the new engine.
10. Join the engine and transmission together. Reinstall in reverse order.
Where Can I Get a New Chevy Engine or a Chevrolet Performance Crate Engine?
We carry a wide range of factory Chevrolet parts including stock engines and models from the GM's performance line. Our site makes it easy to find the correct replacement engine for your modern Chevy and lists all the information you need to pick a crate motor. Still have questions? We have experienced parts people available to answer them so you can be sure you're ordering the right motor for your application. We may be based in Texas, but we can ship engines across the country, often for far less than you can buy them locally.