Welcome! Becoming a registered user of ShortWingPipers.Org is free and easy! Click the "Register" link found in the upper right hand corner of this screen. It's easy and you can then join the fun posting and learning about Short Wing Pipers!

Thanks Thanks:  0
Results 1 to 3 of 3

Thread: O320 (no dash) VS O320-A or B?

  1. #1

    Join Date
    Oct 2020
    Location
    Central Florida
    Posts
    9
    Post Thanks / Like

    Default O320 (no dash) VS O320-A or B?

    I thought I read somewhere on here that there was some debate as to what a "No dash" O320 actually was with respect to the STCs and documentation required to install. When I read the TCDS I see that the O320-A1A is a redesignation of the O320-"nothing". So my question that I'm sure is answered somewhere here is: From the perspective of the various STCs and approvals, is the non dash O320 equivalent to an A1A? It appears to be the same in the TCDS. If not please steer me to your source. I'm not trying to rekindle a huge debate, just trying to understand how to apply this to the approval process and trying to tap into the tribal knowledge.

  2. #2
    Pacerfgoe's Avatar
    Join Date
    Nov 2009
    Location
    Close to Edmonton, Alberta
    Posts
    821
    Post Thanks / Like

    Default Re: O320 (no dash) VS O320-A or B?

    If you look up the O-320 TCDS it explains within that document (about page 5) that it’s a model designation change only.

    So the answer is YES, they are the same.
    Last edited by Pacerfgoe; 01-10-2021 at 10:21 PM.
    Forrest Miller

  3. #3

    Join Date
    Mar 2017
    Location
    Frederick MD
    Posts
    1,043
    Post Thanks / Like

    Default Re: O320 (no dash) VS O320-A or B?

    Note 5 of the TCDS for the O-320 (E274) tells you that the O-320 (no dash) is the same engine as the O-320-A1A. So if an STC lists only O-320, then it would be legal to use that STC with either an O-320 (no dash) or an O-320-A1A. When we look at the TCDS, we see that an O-320-AXX, an O-320-CXX and an O-320EXX are all 150 HP engines. The O-320-BXX, and O-320-DXX engines are all 160 HP engines. The "D" and "E" series engine are for Dynafocal mounts, so if you wanted to use one of those engines you would need to change your engine mount as well. The primary difference between an "A" or "B" engine is compression ratio, the A being 7.00:1 and the B being 8.50:1. Visually on a narrow deck engine this is evident by the banana plates on the cylinder hold down bolts. The higher compression ratio requires higher octane gas (not a problem today as all that is available is 100LL, but the A series is rated for 80/87 Avgas). Other variations within the models would be carburetor, provisions for constant speed prop, magnetos, and prop bolt bushings.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •