Nope, won't foam. You will be fine. All motor oil (dyno and synthetic) has to meet the same standards. Some just have different friction and cleaning additives. They are all compatible. I've never heard of anyone loosing a motor cuz they changed the kind of oil they used. Run what ever you want. It will be fine.

I run what ever is cheapest when I'm at the store that day, and I have a 400+ hp turbo motor. Been running this like that for 25,000 miles and still going strong .

 

For what it's worth, I made this swap several months ago with no apparent problems. No evidence of foaming that I've seen. You should be fine going back to non-syn.

 

do you have any facts to back that up?


If that was the case, why wouldn't it foam when you went from conventional to synthetic? The 2 oil types will still end up in the same engine and, ultimately, in the same oil pump through the transition - no matter if you are swapping to synthetic or from synthetic.


EDIT: This sounds like some trick a quick lube shop would use to get you to continue using the expensive synthetic against your will

 

beat me to it. there is no problem switching back and forth

 

No facts to back it up. Just what I've been told and heard. Never said it was true.
I'll just stick with the Synthetic either way.
That is a good point about going switching from conventional to synthetic. Never looked at it in that perspective.
Though the statement about hydraulics does hold true. I know. I "accidentally poured 3 gallons of the wrong type of Hydraulic fluid in our company's Bobcat!! Boss wasn't too amused either might I add.
Foam was bellowing out the filler tube.

Jim

 

 

No poking just yet. That "Now just sit back and think about it" statement was towards what foam would cause if it were present in the oiling system.
He did ask what would foam in the oil hurt? Therefore, I posted my theory on that one.
It's a catch 22 here. What are windage trays for? Anti foaming part, and scrapes the oil off the crank. Some say a windage tray is worth 10 bhp on an engine dyno. All hell, I just got :
Oh well.
Hell, place some 75w-140 in that engine! It will like it!

Jim