Ask The Experts: The Evolution of Caterpillar Pistons

Here at Highway & Heavy Parts, we're dedicated to bringing you the information you need to confidently buy diesel engine parts, expand your business, increase your profit, and successfully identify which parts will fit the job at hand.

That's why in this post we're highlighting the evolution of the pistons in the Caterpillar 5EK engines.

Caterpillar 5EK Piston

History of Caterpillar 5EK Piston Changes

As you can imagine, pistons have evolved over time to support the high-horsepower diesel engines that are now produced. These changes serve to make pistons more durable and reliable.

These changes affect many diesel engines, including the Caterpillar 5EK, when you replace pistons during a rebuild. If you're working with this Caterpillar engine, you'll want to make sure you're getting the right piston the first time!

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The One-Piece Piston

Caterpillar 5EK diesel engines were originally manufactured with a one-piece aluminum piston. 

During this production time, though, there were changes to diesel engine emission regulations. This significantly altered the conditions inside the combustion chamber. 

As the temperatures and pressures increased, manufacturers began to realize that this might not be the ideal piston for the best performance. They reevaluated what material was the optimal choice for their diesel engines.

The Two-Piece Piston

It was then decided that a more durable two-piece steel and aluminum would be manufactured to better support the changes in operating conditions. 

When you're rebuilding your engine, Caterpillar does recommend moving to the updated piston design. This results in a more reliable upgrade and improved engine performance. 


Updating Your Pistons

What to Know During Engine Rebuilds

At the time of an engine rebuild, a one-piece piston may be pulled during disassembly on early engines. Rebuild kits are still available with the one-piece piston.

However, an upgrade from the one-piece to the two-piece piston is available in rebuild kits for the 5EK engines. It's important to have the engine serial number and the piston number from the original component to ensure you're getting an accurate upgrade.

Evolving to a Higher Horsepower Engine

Changing your engine to a higher horsepower engine, with a different piston design, requires increased cooling of the piston. 

The two-piece piston requires two jets or piston cooling nozzles for a higher cooling volume. This is different from the single jet on the 1-piece piston. 

To support the increased volume needed, replacing the engine's oil pump is required. 

The lubrication system on the 5EK helps to transfer heat out of the engine. When installing the two-piece piston, you also want to update the lubrication components to ensure proper performance. 

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Buying Parts for Your Caterpillar 5EK

If you're sourcing engine components for the Caterpillar 5EK, you'll want to remember that internally it can have different pistons. 

It's also important to note that you're likely working with a rebuilt engine, so the pistons that the engine serial number shows the engine was built with may not be the pistons that are there now.

If your piston configuration is different or changes, you'll also need to change the piston cooler and the piston jet. 

Once you know what piston you're dealing with, you can make sure you're ordering what you need the first time. 

At Highway & Heavy Parts, we're not just selling you a part! 

We're selling an industry leading service that consists of advanced technical knowledge that takes the risk out of buying diesel engine parts.

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