So what's happened Glen? a ring has popped?
I hope so...I suspect the No4 piston has failed around the oil control ring.
But I don't know.
There was no bang, no rattles, no funny noises...just REALLY heavy oil usage and low power...it idles slightly off, but noticably drops No4 once on cam at 4000 ish.
It's using oil, but not burning it...if that makes sense. Black smoke, not blue...and chucking oil droplets out the exhaust.
And it's fouling No4 plug in 100-150 miles.
A CR test proved 1-3 are all Ok...just 4 that's down.