XPBaller

Just like the title says... Why do they say not to run a new engine on synthetic oil?

AdderMk2

$40 for oil and 500 miles is a bit of a waste...

XPBaller

Yeah, youre right. I guess thats a good enough reason lol.



I havnt changed the oil yet, and its at about 1000 miles. im about to change it though and im gonna put mobile 1 in it, so I was just wondering....

67mustang302

Yeah, since the break-in oil is gonna collect up assembly lube and whatever is up in there and get changed, there's no sense in using something expensive. Also rings will seat a bit faster on a standard oil because it doesn't lubricate quite as well, so there's a lil more friction between the rings and cross hatch.

87GT Drop Top

Synthetic oil won't let the engine break in properly. You need to run conventional oil for it to break in.

XPBaller

so when is it 'OK' to switch to synthetic.

AMNick

+1 The main reason. Synthetic protects too well. You need some friction to properly break in the motor or you will have poor ring sealing on your pistons.

87GT Drop Top

I would run the regular oil for 500 miles the switch to synthetic. Check out this link on breaking in an engine.

http://www.mototuneusa.com/break_in_secrets.htm

mjr46

after 75 mile I changed out the regular oil to inspect filter , the first oil I always use inexpensive oil cause I know it's coming out, after that synthetic right in, the way rings and technology is today the iron/ moly ring is seated very quick , almost after the first 20 min of run time, don't believe me?? call fordstrokers.com......either way mine does not smoke or burn oil with the sequence I followed...to each his own

67mustang302

Yeah, like mjr said, your rings will be seated within 20 minutes. I'd just do a ring break in, change the oil and inspect the filter, and then put synthetic in. Whether it's 20 miles or 2,000 miles, the engine is already broken in by that point.