I recently purchased a CH23S Command shortblock to replace the one on my Toro Z253. I've replaced several engines in my 24 years of mowing/small engine mechanic career (any of us who mow wind up becoming small engine mechanics.) I don't use the oil press kill switch on my engines, i always mount an oil pressure gauge so i can keep an eye on the pressure. Initailly i had 38-40 psi when turning 3650 rpms, but after merely 3 hours it had dropped to 20....I called the dealer where i bought the engine and informed them, they said to keep an eye on it and keep running it. When i checked the oil, it was already black with a grey haze (floating metal) and i let them know the oil color and my immediate concern. Engine was purring, no smoke no leaks - full power. After 3 more hours the pressure had dropped to 5 psi and i tool the mower in to their shop. They had a mechanic (per instruction from the area kohler rep) hook up an oil pressure gauge to where the filter connects, and it registered 38psi. I complained saying i know the oil pump is working, but there IS something wrong or that pressure would be making it to the oil pressure port. They said run it. 3 hours later the front seal gives and oil its being liberally distributed via the blower on the flywheel. I called them and they told me to bring them the assembled engine, they'd order a new shortblock and have their mechanic build it. So they call me today and say they won't be honoring the warranty as it was my fault. They say the magnets in the flywheel came off (keep in mind when get a shortblock you reuse your flywheel and stator) and caused the crank to chew through the crankcase....i know i laughed out loud too. ANy way for those of you guys who know engines, i am including a picture to show the shoddy chamferring job to crankcase oil galleys. My theory is the crankcase was improperly machined, causing oil problems/bearing failure (by the way kohler doesn't use bearing in their engines and you can't buy a new crankcase, only a miniblock or a shortblock) and when the crank cut deep enough through the crankcase, the stator met the magnets. Look at this photo...does it not look like a machining defect to y'all?