I have a 25 year old 7 hp Briggs and Stratton that had nothing but a steady diet of Pennzoil 30HD in it. When I tore down the motor for a rebuild I was surprised at how good the parts looked. The cylinder had some scratches but, nothing to worry about.
A few folks here set me straight on my Pennzoil bashing. Also I have the positive proof that it is not the bad oil I was brought up thinking it was.
As for now, I run Havoline 30HD in it. Why? I just like it more and it does not burn off the way Pennzoil does.