Engine to identify

[fnqvmuch]

The latest set posted in the SDASM archives may well be OT but; please, what is this? is it related to the OX-5?
http://flic.kr/p/j6BDJu
thank you in advance,
steven

[daviemax]

[b]Looks to large to be an OX-5. Definitely not a Liberty. [/b

[The Inspector]

Give Aircraft Engine Histories site a look @ 'enginehistory.org I don't see any ignition harness or distribtors so it could be a diesel, maybe for an airship-

[daviemax]

Actually there does appear to be spark plugs and a harness emerging from the longitudinal tube. Not sure about intake valve operation though. Interesting mystery.

[fnqvmuch]

[url][url=http://flic.kr/p/j6BDJu][/url][/url]
just to bump with the photo, having found how to ... still unidentified; I have only found a reference to Curtiss developing but not actually realising alloy heads, etc., for the OXX6.