If you remove the head (carefully, the cylinder will want to come off also) and measure the bore and stroke you can calculate the displacement.  I have a matched pair of 19's that look just like yours.

Hmm, I never knew of a .19 in this style. I knew I could take it apart and measure it up, but I was hoping to take the easy road. 

 Thanks Russell.

It is easy to tell what it is.
Fox made that as a 19 and then discontinued it and made a 25. The 25 has the displacement stamped on the lug the 19 is unmarked. These are actually very good engines but are really favored for speed limit combat rather than stunt. Both of them are excellent running engines.

Dennis

Dennis, do you mean the engine mounting lug?

Yes the upper face of the left mounting lug. pictures of the 19&25 showing the 25 marked

It's a Fox 19. Stick it in a 1/2 A Combat running 10-15% nitro 23% castor fuel (unsilenced) and you should get a good few years flying out of it before it needs anything major doing to it (providing you tighten the mounting bolts down enough; unlike me with my 29X on it's maiden flight! - Engine parted company halfway through testing, carried on running too! (Fortunately no one was hurt and the engine was unscathed:-).


Currently looking for a new club to fly with!


Tim

If anyone has a CL .25 that they will part with. Let me know.

Regards, Phil

If it's a 25 the bore + stroke will be 0.738" * 0.600" (0.700 if it's a 29).

Hope this helps,


Tim