The Mills engine has now been completed but has it started? No not yet BUT it did fire today...blue smoke and all! However before we get to that I decided to try and start her again today. First I made a starter to run in my drill and after that I stripped the engine down and checked the contra piston, and piston in particular.

According to Ron Chernich's article the piston fit was spot on. i.e. the little end moving to the exhaust ports before stopping. It also showed the taper to be correct as well. Looking at the contra piston though, it was a pretty good fit but not as good as the piston so I made up another and made it fractionally bigger. It did not go into the cylinder liner quite as much as the other before becoming stiff. Indeed I would say this one was more on the very tight side, which is what I wanted.

Cleaned the engine parts again in the ultrasonic ring cleaner (stolen from under the nose of 'she who must be obeyed'!) and reassembled the engine. I must admit I was very surprised at the difference in compression for such a small adjustment. But then, I am new to this game........

Armed with renewed enthusiasm, I followed Ron's start up instructions and screwed the compression screw in, between trying to start her. Unfortunately it became a little discomforting so I decided to use the startering adaptor I made earlier. After three or four more adjustments to the compression screw, the thing fired! Whereas I 'hoped' I felt it fire before, I now know it didn't, because this was completely different. This time there was a puff of blue smoke from the exhausts and a definite smell......(no comments please).

I thought I would go back to the manual method again, as it may be near its setting, but it was too difficult. So I decided to retire before I broke something, and will try again tomorrow.

I may make another piston though, first thing, and see if this will make as much difference and the contra piston did. Its easy to dismantle the engine and change things.

I marvel when dissabling on how few parts there are, compared to how long it took me to make the thing! It is a simple job to disassemble and reassemble so hopefully I can report a more positive result soon..........

Main build covered on the website www.mikes-models.com