I have one myself from my free flight and control line days. Mine has almost no run time on it and I have had it for over 45 years, I think I was thirteen when I bought it.
I can pull it out and look if no one in the know helps you but I think it was just A bushing installed in the front and it's A press fit. Been A while sense I looked at it. If so you may be able to go to any bearing shop some place like King Bearing and buy what you need and fix it yourself with some help from your dad.
You may want to post this on one of the engine sites instead of kit building though. Just A thought. PM me if you need some help and I will see how mine is made.