Hi there. I recently aquired this old O&R .29 glow engine yesterday. I have not had anything this old before, and would like to see if anyone here would possibly be able to help me identify anything about it. From what I have read before, I do not believe that this was a fuel to nitro conversion. However, I may be wrong. The plug in it is a Champion glow plug. Mainly, I would like to know what year it was manufactured, serial number 001906, what propeller to use, and what fuel to use in it. I have and use Omega 5% nitro with addes castor, as well as a little bit of Sig 5% nitro 25% all castor. If only for bench running a time or two, would either be ok? Also, there appears to be some sort of 'clip' in teh venturi held in place by the needle assembly. Lastly, what propeller would one suggest on this old engine. The one on it is 8 x 4 I believe, but the finish on the wood is cracked and peeling so am unsure of running it and would rather but a new propeller. Thank you in advance for any and all help you may be able to give.

Also, this will be cross posted, so if you see it elsewhere, please disregard.

Jim is correct.
The case modification indicates that the motor is after 1949.
The 'cover' is where the points rode for an ignition motor.
Most of the glow motors had black covers.
The 'clip' MUST be inside the venturi of you are going to run it.
Have several of these and so did my Dad.
Use lotsa cator and easy on the nitro. 29/5
The cylinder head is staked on, so too much nitro and you'll "Blow your top!"
Dad built a Comet 54" Taylorcraft back in the day, added a plywood bulkhead, landing gear mount and sheet balsa on the top of the wing and the nose to behind the wing. Covered it in silkspan and added a little yellow dope. We called it "The Paper Cub"!
The O&R 29 was radial mounted and the plane had large Trexler air tires. What a joy it was to fly! Flew it for years! Still have the landing gear & tires!
SOMEWHERE....... I have a listing of O&R serial numbers and the years they were used. The thrill of the hunt!
"Tight Lines!"
Wes
P.S.: We used two of the large Bell Telephone big cylinder type batteries taped together, wired in parallel. Lasted a LONG time!

You have an O&R 29.  It was intended for glo use.  Previous suggestions for fuel and prop are correct.  I have run many of these engines with a 10-5 wood prop.

Before building a plane for it, do some bench runs.  Be very aware that the gasket between the cylinder and crankcase often develops leaks.  This cannot be fixed easily.  If it leaks, you will never get it to run reliably.

Here is the same O&R 29 engine in a light weight Go Devil.

Old engines are nice.  However, the O&R 29, or any O&R engine is not a collector item.  They are not very useful for C/L.  Bottom line is;  they have very little cash value, even one that looks new.  They were high volume production, so there are probably more of these still surviving than any other types.

The O&R engines are still used in some types of old time free flight events, sponsored by the Society of Antique Modelers. (SAM)