onan L series / cummins A series - Diesel Forum - TheDieselStop.com
General Diesel Discussion about diesels in general. All brands are welcome, please refrain from brand wars. Discussions about types of diesel fuel also go here.

LinkBack Thread Tools Display Modes
post #1 of 1 (permalink) Old 10-05-2007, 06:04 PM Thread Starter
Junior Member
Join Date: Oct 2007
Location: Finger Lake, Alaska
Posts: 4
Feedback Score: 0 reviews
onan L series / cummins A series

I found and old posting from a few years back called 'Is It True?' The onan L series engines were designed and built by onan for use on their DL series of gensets. They came in 3,4,and 6 cylinders with displacements of 1.7L,2.3L, and 3.4L respectively. Model designations were derived by using engine series (L) followed by number of cylinders, then displacement in Litres. Therefore, the 4 cyl was called and L423. These engines ran generator sets in the range of 15kW to 30kW. They used the Onan YD generator end. When these engines were developed, Onan was its own entity, unrelated to the Cummins Engine Company.
Upon the purchase of Onan by Cummins in 1986, Cummins used its own designation on these engines, similar to those already used on the B and C series Cummins engines already in production at that time. They called this new, smaller engine the A series. Designations were number of cylinders, followed by series. Therefore the engine with an onan degignation of L423, became the Cummins 4A. These engines were phased out by cummins quite early, and are now nearly extinct, and very hard and expensive to get parts for. I still occasionally see some of these here in Alaska, and worked on a few when I worked for the Alaska Cummins distributor as a field generator tech. I also have a 4A myself.

The Cummins B and C series were developed by a joint venture formed by Cummins Engine Co. and JI Case in the early 80s. Both companies were headed for bankruptcy, and joined forces to create the Consolidated Diesel Co, with engineering performed mostly by Cummins, and manufacture handled by JI Case. The resulting engines created the new midrange family of engines for Cummins. They were called the 4B,6B,and 6C, with displacements of 3.9L, 5.9L, and 8.3L respectively. These engines were used by Case wherever possible, and found their way into almost all of their products. Cummins used these engines for industrial, generator drive, marine, and automotive applications in order to maximize their market coverage with minimal investment in the product. The 6BT found its way into the Dodge D/W250, and 350 trucks for the 1989 model year. The first Dodge/Cummins used a rotary injection pump (Bosch VE), and was rated @ 160HP. In 1991, the engine was intercooled, using a Charge air cooler, still using the VE pump, and still rated @ 160HP. 1994 saw an inline injection pump added (Bosch p7100), and a rating of 180HP, using a wastegated turbo. 1998.5 MY introduced the ISB 24V electronic version rated @ 235HP.
So there is no relationship between the Onan L series (Cummins A), and the B and C series engines.

Valley Skunkworks
1961 Coupe DeVille, soon to have Cummins 6B
1979 Mercedes 300CD
1981 Volkswagen Rabbit Diesel
2005 Dodge 3500 Diesel
mvw is offline  
Sponsored Links

  Diesel Forum - TheDieselStop.com > Other Topics > General Diesel
Gear in this thread - Powered by O'Reilly Auto Parts

Quick Reply

Register Now

In order to be able to post messages on the Diesel Forum - TheDieselStop.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome