would you cause harm to your engine swithing from regular oil to synthetic all at once?

 

I think the damage comes if you switch back from synthetic to regular oil... You shouldnt have any problems going from regular to synthetic.

 

no you won't hurt the engine

 

I've heard that you can switch back to regular old dyno oil from synthetic without any problems now also. Can anyone back this up with some solid evidence?

 

Petroleum -> synthetic:
Only potential issue is heavy deposits from the petroleum being loosened by the synthetic and contaminating the oil prematurely. Worst case is the pick-up screen getting plugged and starving the pump. Deposits have to be very thick in order for this to happen - In 20 years, I've seen it happen once (the car had been rescued from a trailer park flood, if that gives you an idea of its previous life's maintence).

Synthetic -> pertoleum:
Only issue is you're going from the good stuff back to regular stuff. Wear rate will increase, but no more so than it would be if you had never used synthetic. The crankcase should be cleaner after using synthetic, though.

These are general statements, and may not apply to every Tom, Dick & Harry's brand synthetic.

 

so basically no, and also no if you put synthetic in and then later switch back to regular oil.