Watch: Step Inside Your Perkins Engine For a Virtual Tour, It’s A Fascinating Place

A diesel engine is conceptually simple. The piston compresses air in the cylinder which raises its temperature. When it’s hot enough to ignite diesel fuel, some is sprayed into the cylinder and the combustion drives the piston down. That motion is transmitted to the crankshaft through the connecting rod causing it to rotate, making horsepower and torque available at the output end.

Turning that concept into a practical engine, however, is anything but simple. It takes some truly amazing engineering to contain and harness the immense internal forces involved while meeting modern requirements for efficiency, reliability, fuel economy and, of course, emissions.

We’re surrounded by the products of that engineering every day in the engines that power the machines we use to make a living. But, knowing what actually goes on inside the engine has mostly been the province of the engineers who design and build them.

It’s a fascinating place, and Perkins has created a series of short animated videos that let you take a look inside for the first time. Performance Under Pressure, is a unique tour of a typical 4.4 liter Perkins engine. It shows not only what’s happening there, but also why it is so important to protect the critical components with genuine Perkins products designed by the engineers who know exactly what’s needed.

The tour starts in the combustion chamber. There the expanding gasses produced by the burning fuel exert 14.3 tons of downward pressure on the piston crown, about the weight of a dozen typical cars. All of that force is transmitted from the piston to the connecting rod through a 3/4” diameter steel pin and then to the crankshaft pin journal 750 times a minute. This constantly repeated force can cause lower quality pins, crankshafts and bearings to fail prematurely, which is why Perkins crankshafts are designed and built with the strength needed to withstand massive and sustained pressures.

The actual pressure inside the cylinder is between 2,175 and 2,250 psi which is equivalent to being almost 5,000 feet under the ocean. That pressure has to be contained in the cylinder by the head gasket to prevent leakage that could lead to engine failure. Poor quality or ‘will-fit’ gaskets may not be up to the job, but Perkins head gaskets are engineered to handle high combustion pressures and keep them inside the cylinder bore.

The fuel injected into the cylinder to create those pressures has to be exceptionally clean because modern fuel system components like pumps and injectors are built to extremely tight tolerances. Even particles as small as 4 microns (0.000157 inch) can cause wear and damage that reduces efficiency and increases emissions. You can’t see them without a powerful microscope, but they can destroy critical fuel system components nonetheless.

Perkins engine

Perkins® Ecoplus fuel filters remove particles smaller than 4 microns to protect those vital components using a combination of advanced filtration technologies. Key features of Ecoplus technology include:

  • Acrylic beading and spiral roving to prevent media bunching and reduce media flex.
  • Advanced multi-layer cellulose/synthetic media to increase dirt-holding capacity.
  • Molded urethane end caps that seal against the housing to help eliminate potential leaks.
  • A non-metallic center tube that eliminates the potential for harmful swarf and resists collapse during pressure spikes.

The air required to support combustion also has to be clean. A cubic mile of typically polluted city air can contain almost 3 tons of dust and grit. Contaminated combustion air is not only a wear issue for pistons, rings and cylinder liners, every particle also has the potential to damage turbochargers and inlet valves and cause even worse damage if it gets inside the combustion cycle. It also can impact the performance of the engine’s emissions control system and reduce fuel economy by altering the precisely calibrated fuel/air mixture.

An efficient Perkins air filter that’s precisely matched to the engine’s requirements effectively protects it from dust and grit ingress. Air filters are simple, inexpensive, easy to change and should not be overlooked during routine maintenance because the protection they provide is every bit as important as that provided by oil and fuel filters.

All of the moving parts inside an engine require clean oil to provide the lubrication that maximizes their life. Contaminated oil quickly leads to excessive wear, loss of performance and ultimately to premature failure. In just 24 hours of operation, the oil filter cleans over 21,000 gallons of oil, enough to fill two typical tanker trucks.

Perkins has applied the proven Ecoplus technology to the oil filters used on many of their latest engines. But regardless of whether the filter used is an Ecoplus or conventional screw-on, saving a small amount of money on a ‘might work’ aftermarket oil filter instead of a ‘designed for the job’ genuine Perkins filter puts the turbocharger and crankshaft, conrod and camshaft bearings at unnecessary risk.

The high temperatures generated by the combustion process are controlled by the coolant circulated by the water pump. The pump circulates more than 95,000 gallons of coolant every 24 hours of operation, enough to fill 2,378 typical bathtubs. If the water pump isn’t up to the job, the result can be tiny bubbles of hot gas that erode metal surfaces inside the engine. You won’t see the damage until it’s too late, and the consequences can include leakage and even engine seizure. Perkins water pumps are designed to maintain correct coolant pressure and flow under all operating conditions.

Even the starter motor used in a Perkins diesel engine is specially engineered and tested 36,000 times, equal to 10 starts per day for almost 10 years. Like everything else on a Perkins engine, the starter motor is designed to resist the massive forces involved, this time on the gears that engage the flywheel. They’re built to be reliable even in extreme environments.

What goes on inside your Perkins engine really is amazing. Using genuine Perkins maintenance and service parts installed by factory-trained technicians from your local Perkins distributor is the best way to continue enjoying optimum engine performance.

Now that you’ve read about it, why not take a virtual look inside a Perkins engine to see how all of those components and systems work together to generate reliable, efficient power. Watch all three parts of Performance Under Pressure at


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