How can I decode Lycoming engine number suffices? What does D3G mean in o-320-D3G or D2A in o-320-D2A? Is there any chart or tabel for decode suffixes?


2 Answers 2


I got the following information for this website:

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Also if you scroll down here you can see the model numbers that you talk about in your question.

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The last character seems to be an indication of the variant of the engine as shown in the document. The D indicates Dual Magnetos and the 2 or 3 seems to indicate some type of counterweight application.


This PDF on Lycoming's web site covers it. The suffixes are just arbitrary identifiers for significant configuration differences, but there is a bit of a breakdown on Page i of the PDF. Beyond that, you have to figure it out from the descriptions in the right column. If you study them the logic should start to emerge.

  • $\begingroup$ He didn't say about suffixes that's my problem $\endgroup$
    – Arian
    Sep 17, 2019 at 18:10
  • 1
    $\begingroup$ You should copy out and cite relevant portions of the linked page, links die, pages change, sites get shut down, etc. "Link only" answers are very much discouraged. $\endgroup$
    – Ron Beyer
    Sep 17, 2019 at 18:41
  • $\begingroup$ He needs to see the entire document, not just a sample. I changed the link to the root document on Lycoming's site. That link shouldn't be going anywhere. $\endgroup$
    – John K
    Sep 17, 2019 at 19:08

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