Originally Posted by bubbatime
Most likely hours used (lots), out of round cylinders, and carbon'd up rings. If its a lower hour older engine, that is in good shape internally, then it will probably be fine. I've seen it so many times personally though, that my standard is to just use conventional oil in older engines.
Thanks for sharing your insight. Of these three things, I can't see lots of hours or out of round cylinders making much difference when it comes to choice of oil. Am I missing something? As for carboned or coked up rings, would the synthetic oil maybe start to clean and free that up, possibly even bringing the out of round cylinders back into play? Just thinking out loud here.
Originally Posted by bubbatime
But when we get down to brass tacks, what difference operationally, if any, is there between Pennzoil yellow bottle 5W30 in a snow blower, rather than Pennzoil synthetic 5W30? What proprieties, does the synthetic really offer? High temp stability? Not needed, as the engine will never be over 185 degrees. Cold start pumpability? What's the difference between the two? It probably doesn't get cold enough in most places to make a difference.
That's a reasonable question. My best guesses are 1) synthetic might buy you some time while operating on a steep grade where the slinger can't grab any oil, and 2) synthetic might do a better job of keeping the rings from getting coked up in the first place. Obviously none of this contradicts what you first said, but it is interesting to think about.