Originally posted by Roger
Just picked a new P5 motor 2 weeks ago and decided to put it into my 1/8th scale buggy since I had time this evening. Installed it into my buggy and tried to fire-it up for the break-in process. It turned over for about 4 seconds and then all of a sudden, it seized. Tried to turn it over again and noticed that the flywheel wouldn't even move. Took the motor out and tried to turn it by hand, it wouldn't move. Took off the back plate, and noticed small pieces of metal. Took of the head and sleeve and it still didn't rotate. Removed the piston/rod, and one side of the piston was toast 
. Has this happened to anybody else breaking-in P5 novarossi motors ??
I know this is to late, but if you didn't, you should ALWAYS ALWAYS pull down any new motor and clean it thoroughly before running it for the first time. Quite often you will find small metal shavings left over from the manufacturing process. These can obviously cause major damage to your motor like you have described.
Regardless I would return the motor to the distributor for him examine. In most cases like these the distributor will provide the customer with a new Piston, Liner, Rod if it can be shown the goods were faulty.
Cheers Alastair