Trojan Croydon Engine 1950s

Few weeks after moving into a new place I found a local ad saying there will be an old car workshop auction and everything must go. It was my first auction and unfortunately I didn’t thought that I need to dedicate all day for such an event. Tools and garage equipment were selling so cheap that it took me a while to realise its true not some hidden sales joke.

Also I had just a few free hours and not a lot of savings left after the move so had to bite my tongue and see nice things being given away for pennies. After exploring the whole place I climbed in the attic and found an engine. Small engine. Old and small and interesting and I must to have engine. It wasn’t listed anywhere on a sale so I found the owners and gave them 20 dollars, put it into back pack and ran away all happy. And here it is – 49cc, two stroke Trojan Croydon engine manufactured by Mini-Motor (Great Britain) LTD.

The more info about the history and specifications can be found here:
PAGE 13. Trojan History: Mini-Motor; Raleigh All Steel Cycle & 1958 RM1
My engine number is MX 15066 W. According to the limited database, this particular model was produced in 1950 to 1951. Unfortunately I couldn’t find the explanation of stamped letters. In fact, the engine case more stamped random letters all around. Maybe someone practised using stamping punches before did the right job?

Few fins missing from the cylinder head and the cylinder itself. The piston does look like a work of art. Googled Polson Pistons and all I could come across was a record of 72 pages Piston rings and ring sets catalog published by Polson Motor Parts Company Pty Ltd in 1955. But no actual access to a book or any other info about the company. I guess it is an aftermarket piston made by that company. Someone took away Piston rings and it might be a challenge to find a replacement ones.

Had some trouble taking magneto off. That thing well stuck and event had to go and buy a new gear puller. It did bend end of the crankshaft thread when I tried to remove it but it’s easily fixable. Eventually Wipac magneto, that was manufactured in Bletchley, UK, popped off like a firework. Note to myself: get your own sandblaster!

Engine case split easily. One bearing was disintegrated and all the rollers poured out loosely. Con rod looks interesting and simply cut from a 5mm sheet. Even bottom end roller bearings are wider. I will try to stay away from splitting crankshaft and doing major restoration. First of all, it will be just a display engine, no need investing money and time. Secondly, I don’t have machinery or tools (yet) to do a proper job.

Managed to quickly sandblast cases before I left work. It didn’t got rid of everything but will definitely save a lot of cleaning time. Haven’t touched outsides as it looked too shiny to be ruined after soaking them in a parts washer for a half of the day.

Rest of the bits were also sandblasted when I had a chance. Also painted and put on a shelf. Awaiting for the assembly. Ideally would love to polish aluminium parts but once again, too expensive for such a small project. Probably will do bolts and inlet manifold zinc plating (yellow) and leave rest of the parts how they are. Still thinking where to find right piston rings, because would love to start it up once it’s done.

Will be updated once I get bearings and seals…