Crankcase upgrade/repair

There I was starting to prepare for the Cox flight contest and deciding which engine I could use. Difficult decision in my case - too many options.

Anyway, it had to be beam mounted for the aeroplane I have chosen (this has arrived but I am still waiting for balsa cement and dope - no longer can I walk to the local model shop! - everything has to be mail order.

It also has to be quiet and so needs a good silencer (muffler) and a bit of throttle control. Matt had supplied me with a Hiscott muffley thingy and so I selected one of my restored Medallions to go with it.




It looks the boy but was not to be a runner at the first attempt!

I was prepared for a lot of messing about with heads as the Hiscott system raises the cylinder and reduces the compression. Messing about turned into two and a half hours of flick - flick - flicking!

It started a couple of times, ran for a couple of minutes and then stopped abruptly. It would not restart while hot.

I thought it was compression and I had not chosen the right head, number of gaskets and so on.................

However. when it ran - the silencer was superb and the throttle control was excellent - along with idling.

After a while I notice fuel spewing from between the prop driver and the crankcase. Further examination showed that the crankshaft was a sloppy fit to say the least!

So ...... not being one to scrap anything - it was time to strip the thing a let it visit the workshop. Where it was.........

drilled and reamed



a suitable piece of brass selected



I made a mistake and turned it too small and so worked further on it for a Bee crankcase




anyway - back to the Medallion





off to the mill!








Reassembly ready for testing. Too late to test tonight but fingers crossed for tomorrow. What am I saying? Better not cross my fingers while flicking the thing!