>>>*One thing I am sure of is that jazzing the throttle to 3000 RPM or so won't float a valve, in fact, stock springs in good shape will still hold her at 6000 RPM in that situation.
Even if someone did get over the top on RPM, at the most she might bump and bend a valve long before a rod or bearing would be harmed.
The highest loading doing that would be on the timing chain tensioner, which is the notorious weak link. Vertical engines create a pulse on the chain which basically gives it a nice jerk each time she passes TDC. Nature of the critter.
Then since doing that causes oil to be slammed into critical areas, the oil wedge will hold metal apart and it will never even touch.
So, the only ways to do a bearing in are lack of oil and no fit in the first place. Wear can build up over time of course, especially with engines in vehicles that sit unused for very long periods.
We had one gentleman locally order parts and build his 22RE, it sounded like a diesel when he got her running. Three months he drove it back and forth from Portland to Longview that way on the freeway at 70 MPH, finally one day he drove in to have me try to "adjust" his valves since he just could not get it right.
I couldn't get them right, either, since he had standard bearings on a .010"/,010" undersize crankshaft. We lifted that one out and slid in the right size bearings for him and she is running today, it didn't hurt a thing, just rattled.
He wondered why he only had 15# oil pressure at freeway speed...*LOL**...yep, tough little critters...
Now, get a crankpin out of round, or a rod big end off size, or the timing off far enough to create some detonation?..?..Yep, she won't last long..*EB
