Agreed. This was / is an awesome thread. Dave's pictures were awesome. I'm glad he had the cojones to tear into this engine. I hope he gets it, or has gotten it all squared away.
I'm a little confused, or just don't know why he didn't go back with an original 3A92 piston so as not to have to make modifications to the Toyota one. I guess I have read that Mitsubishi parts are difficult and/or expensive to get. Maybe that's the reason.
But I would be a bit leary to machine down the crown of the piston (for cylinder clearance). I would be concerned thinning that piston material thickness might lead to problems (I only speculate, no expert here for sure). It would be nice if the wrist pin location in the piston could be modified ... but I cannot imagine that being possible ... at least without serious machine work (welding-machining), cost, and imperfections to that process leading to all kind of piston problems (piston rocking, etc).
Even if Dave had brand new perfect OEM parts to rebuild with, I'd also be concerned about the problem happening again.
The one thing I will say, that you guys have already pointed out - This does seems related to cold climates and over-rich to engine flooding issues. I think I'd run a block heater on these suckers if at all possible if I lived up yonder.
__________________________________________
View my fuel log 2020 Mirage ES 1.2 manual: 42.5 mpg (US) ... 18.1 km/L ... 5.5 L/100 km ... 51.0 mpg (Imp)