Ring Set Instructions For Detroit Diesel Engines

June 21, 2022

What You Need To Know About Ring Sets For Detroit Diesel Engines

In this article we will talk about what ring sets are, what their function is, how to select the correct ring ,and how to install them on your pistons. Proper ring set selection and installation is important for the performance of your engine and proper oil scraping. We will also include an informative video showing you an installation of rings at the bottom of this article. 

What Are Ring Sets?

Ring sets are the set of rings that you will be installing on the pistons of your engine. There are three types of rings that you will find in your ring set. The expanders, oil scrapers (oil control rings),and the compression piston rings. Each of these has its own function and is vital to the performance of your engine’s combustion cycle. 

The expander ring before installation onto the piston.

The oil scraper rings (oil control rings) before installation onto the piston.

The compression piston rings before installation. 

What Is The Function Of A Ring Set?

The function of your ring set is to form a seal between the piston and cylinder wall, which prevents pressurized combustion gasses from entering the oil sump. They also regulate oil consumption by preventing excessive oil from entering the combustion chamber and burning. Properly functioning rings are vital to maximum engine power and efficiency. The piston rings themselves are designed to be part of the combustion process along with the pistons. 

Selecting The Correct Expander Rings From Your Ring Set

It is important to select the correct rings for your application since there are two types of expander rings that will come in your ring set. Below we specify which expander ring to choose based on your engine’s application.

For  92 series engine ring sets always use yellow painted expanders for (high tension) non turbo and transit bus applications and green paint for (low tension) for other applications.

 For  71 series engine ring sets use the white paint for non-turbo (high tension) and transit bus applications or orange (high tension) for other applications.

Installing Your Ring Set 



  1. The correct expander for your application should be installed by hand with the free end facing upwards in the oil ring grooves in the piston skirt. 


  Note – Do not cut off or grind the expander to prevent overlap. This can cause the tension to decrease on the oil  scrapers (oil control rings).


   2.Lubricate the oil scraper rings (oil control rings) with STP or equivalent and install by hand starting with the upper half of the top oil ring, align the gaps. Note that the scraper edges of all oil scraper rings (oil control rings) must face downward (toward the bottom of the piston) for proper oil control. 

  3.  Installation of compression rings should be done with tool J 8128 not by hand. Avoid overstressing the rings and do not spread them anymore than necessary to slip them on the piston. 


  • See Service manual for complete instructions and notices on the installation process. 


Follow by Email