I heard it’s possibly a tolerance issue at the crank shaft......engine gets hot and theres not enough space for parts to expand......it would probably only take a few thousandths of an inch to be an issue.
“I heard it’s possibly a tolerance issue at the crank shaft”
Here’s some trivia, not really related to the Toyota problem, that a aircraft engineer told me.
Pressure-lubricated sleeve bearings, such as crankshaft bearings, don’t wear once up and running because the shaft is floating on oil and not touching the bearings. Wear only occurs at startup when the shaft is resting on the bearing and before the lubricant film gets in between.