My friend's LST had the same problem with the Mach 26. The piston broke very soon after the break in period. The engine was repaired under warranty, but unfortunately soon afterwards then the conrod punched right through the block!! It was one of the most spectacular engine failures I've seen.

With the NS S 25 engine that comes with the Savage, I inspected mine prior to doing the running in procedure. It was not only rusty, but poorly lubricated and full of metal debris/swarf. I'm certain that if this engine hadn't been thoroughly flushed through with alcohol and re-lubed, it would have been damaged as soon as I attempted to start it. The running in procedure would have been pointless. As it happens, this same engine has now had over 12 gallons through it and has been ported twice!

I suspect that most engines end up being run without being properly prepared. In some cases, maybe these particles that are present inside all new engines, are too small/fine to do major damage. But in other unlucky engines, perhaps these particles are big enough to do serious harm to the liner and possibly the bearings, conrod or even the case?

Just a thought.