Todd, Mobil says you can switch back and forth whenever you want but they don't recommend switching to it in older engines (engines with lots of miles or haven't been apart in a while) because it will clean all of the sludge out that's keeping the gaskets from leaking. Matt Todd Tomason wrote: > Bruce, > > Great information on synthetic oil. Where does this fit in on the issues with > low zinc killing cams in flat tappet engines? Is synthetic safe for these > engines? Also, should conventional oil be used for break-in before switching > to synthetic? When is it safe to switch? > > Thanks, > > Todd > > On Thursday 09 August 2007 21:33, Bruce Hevner wrote: >> I have been watching the Syn lubes thread. > _______________________________________________ > Amc-list mailing list > Amc-list@xxxxxxxxxxxx > http://www.amc-list.com/mailman/listinfo/amc-list > > > -- mhaas@xxxxxxx Cincinnati, OH http://www.mattsoldcars.com 1967 Rambler American wagon 1968 Rambler American sedan ================================================================= According to a February 2003 survey of Internet holdouts released by UCLA's Center for Communication Policy, people cite not having a computer as the No. 1 reason they won't go online. _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://www.amc-list.com/mailman/listinfo/amc-list