I have this O&R 19 side port engine that I am thinking about trying to run on ignition. While looking it over and mounting a prop I noticed that the crank shaft splines will not allow the prop to seat against the drive washer, if I were to force the prop on while tightening the nut the splines would crush into the back of the prop. I have removed the shaft to see if the thrust bearing or spacer was missing. The bearing is there, however it appears that maybe the back part of the bearing is missing. What I have is the center bearing cage with the balls and the cup part  over that, there is no cup part on the back side against the crank counter balance. This may sound confusing but don't know a better way to explain it. I figure anyone who has experience with this  engine may have run into this problem before. Richard

Thanks Chris,  According to the article it appears I am missing the rear cup part of the bearing. Richard

Now the washers removed.

Thanks all who responded. Very informative reply's! I notice the article referred to by Chris states the crank shaft ball bearing is made up of three parts, two cupped washers, one on each side of the center bearings cage. Jim, you say the bearings only have one cup washer with the bearing running against the crank, which is the way mine is. The idea of replacing the ball bearing with brass washer sounds like a good idea. My first model airplane engine was an O&R 19 side port sparky as a Christmas present. I spent most of the day just holding it in awe. I was a few days later before I could run it since I had to buy a coil, condenser, white gas and 70wt oil. I picked this engine up at a swap meet. It looks almost new and has good compression. I need to come up with a mount adaptor also. By the way my thrust washer is not concaved so it must be some other reason the shaft seems to long and wont allow the prop to fit without the shaft spines crushing the prop. Richard

Richard, I have a 23 sideport that is the same way. The splines stick out past the drive washer. I usually ream out just a little of the back side of the prop to clear it. Ohlssons do seem to hold up pretty well. I have three of them. A 60 front intake, a 60 sideport, and the 23. I fly the 23 on a 60" Lanzo Bomber with a radio, and the 60 sideport on an 80" playboy Sr. Lots of hours on both and they still run fine.

It may be that someone took out one of the races on both of our engines as Floyd says they should have both. But, mine was never run when I got it and it had one flat race like yours. My 60 had two cupped races like Floyd says. The very thin flat races like used in the Super Cykes are the ones that fail. I know of at least 4 engines ruined by them. I have a freind that I told this to and he pulled his apart to find it was just about to fail. He replaced it like I do. I have never heard of an Ohlsson failing, but that does not mean they can't. I probably go overboard on some things as I did loose a good running Super Cyke because of the bearing.

That looks to be a little farther than mine. It could be spaced back a little by adding a shim to the thrust bearing or just making a thicker bushing than the bearing that is in it. As long as the shaft does not hit the back of the case it should be good when you have a prop mounted I would think.

Looks like it Richard. I have not seen one like that before. If I remember right the ones I have do not have that cut on them. I have a 29 glow that I believe has an ignition crank in it though.

I just checked another front housing and shaft for I believe a 23 sideport and it does have the double cupped ball races on the thrust bearing. They also look to be a lot heaftier than the Super Cykes. I have two spare shafts and neither one have the undercut, but they are both sideport shafts which would stand to reason. I think the undercut shafts must have been only on front intake models.