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Ultimate Guide for Cummins ISX Maintenance and Performance

Written by the Brant Jones Team

You will need to pay attention to numerous facts at the time of maintaining the Cummins ISX engine. If you fail to pay attention to these facts, you will not be able to end up getting the best performance out of it. However, most people get confused when they take a look at the ways to maintain the Cummins ISX engine. That’s why we thought of creating comprehensive guidance on Cummins ISX maintenance. 

What is the Cummins ISX engine? 


This engine type has grown in popularity as a power source for off-road and vocational hauling applications. With a rated power of 430 to 650 hp, these modifications are worth noting whether you're fixing an engine or executing a thorough overhaul.

The design of the cylinder liner has undergone five revisions. IPD produces and sells a wide variety of replacement components for engines from Caterpillar, Detroit, Cummins, Diesel, Volvo, and Waukesha. When maintaining ISX engines, it is essential that buying and service employees be informed of the changes in engine designs & installation techniques - otherwise, serious difficulties might emerge. Excessive engine component wear, early failures, needless downtime, or even disastrous engine damage are all potential issues.

Here are five recommendations to assist fleet experts and engine rebuilders to repair Cummins ISX15 engines more efficiently and effectively, saving time and money in certain circumstances.

Camshaft bushings with a press-in design

The injector camshafts on older ISX dual cam engines are huge in comparison to the valves camshaft, with a journal width of 85 mm (3.346 in.) and a weight of over 65 pounds. While it is normal practice for other engines to drive the camshaft bushings in, installation instructions stipulate that the cam bearings must be pushed in (rather than driven) and pre-lubricated. According to numerous cylinder head rebuilders, the bushings cannot be pushed in without distorting or otherwise injuring them owing to the size and quantity of retention (crush) keeping the injector cam bearings in place, which might lead to bushings failure whenever the engine is placed into operation.

Given the pressure on the injector sprocket bushings, the timing of pressurized lubricating oil reaching the bushings (through the big oil hole within the camshaft) is important.

When maintaining Cummins ISX15 engines, it is critical to research and comprehend manufacturer updates and revisions in order to pick the necessary components for your individual application and to follow current procedures.

Select the proper type of connecting rod bearings.

Cummins ISX series engines employ three distinct varieties of connecting rods, thus it's critical to use the right bearings when changing these components. Early engines use quasi rods with no oil route passing through the rod. Later engines use two kinds of drilled rods: saw-cut and fractured. These are the surface between the crankshaft and the rod cap.

It is vital to match the rod with suitable bearings. The top and lower bearing shells of the saw-cut crankshaft bearings (large end) are made of steel. The shells are labeled with their respective places and have slightly offset tabs.

This bearing casing design does allow for installation mistakes. In fact, you may install them improperly and still attach the rod onto the flywheel. If this occurs, the rod will not receive the necessary oil supply, and the motor will fail. The fractured kind of rods also need upper and lower supporting shells; however, they cannot be put improperly owing to the design.


Keep particles out of oil ports and passageways.

Gasket replacement is an essential component of any in-out engine refurbishment. When repairing ISX series engines, full gasket sets should include a number of tiny plugs to protect the oil ports of the cylinder head as well as the engine block from dirt or even other debris. This is a critical process to follow. In reality, according to most bearing manufacturers, the presence of dirt or other objects in oil channels is a significant cause of bearing failure. Debris accessing the cylinder ports and tampering with the upper bushings and camshaft is also a risk.

Make use of the specialized piston installation tool.

Cummins ISX15 cylinder liners have a detachable APR that extends beyond the liner bore. This ring's function is to remove combustion byproducts from the piston's top section. This helps to avoid bore cleaning of liner walls, which may result in much higher oil usage. Bore polishing is a kind of surface wear that harms the liner's surface.

To use the cylinder installation tool, first, remove the APR rings from the liner, then insert the unique tool and finish the piston assembly. The piston placement tool prevents your piston rings from extending into the APR groove, allowing the piston to slide smoothly into the cylinder. Each engine kit purchase presently includes a specific installation tool. The new APR cylinder is injection heat-treated, has a pinpoint accuracy ID, and an OE-style APR graphite scraper ring. This liner also includes a quality brass shim for simple installation.


Always go ahead with up to date replacement parts 

The Cummins ISX class engine massive changes are built around cylinder kits. Many off-roaders and engine rebuilders understand the need of selecting cylinder kits that match the most recent design modifications. For example, the most recent upgrade of the OE piston for ISX15 engines has a unique bushing-less design with a closed skirt designed to function with APR cylinder liners.

These are substantial design changes. Unfortunately, not all component vendors are able to keep up with the most recent OE design modifications while remaining competitive. To guarantee longevity, endurance, and interchangeability, find a parts supplier that prioritizes replicating OE upgrades for product lines wherever feasible.



Final words

Now you are aware of some useful tips related to Cummins ISX engine maintenance. Keep these in mind and go ahead with proper maintenance of the engine. Then you can experience long-term durability and boost the performance of the vehicle.


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