Mineral based oils vs synthetic oil

[Bronco95125]

I used a SAE 10w-30 mineral based oil to break in my motor. I was thinking of changing to the Royal Purple SAE 10w-30 synthetic oil. I recall hearing switch from a mineral based to a synthetic oil isn't a good idea. Any info would be great.

[904Bronco]

Re: Mineral based oils vs synthetic oil

I used a SAE 10w-30 mineral based oil to break in my motor. I was thinking of changing to the Royal Purple SAE 10w-30 synthetic oil. I recall hearing switch from a mineral based to a synthetic oil isn't a good idea. Any info would be great.

You have to use a mineral based oil with zinc on a solid tappet cam during break in... Not on a roller motor though... Once the motor is broken in, you can switch to Syn. The rumor is that: a motor with alot of miles on it, that sometimes if you switch to Syn from a mineral based, the seals and gaskest may start leaking. I will be switching my 7.3 diesel motor over to syn this summer, it will have 115k on it then. I hope that there will be no issues...

[CityHick]

Re: Mineral based oils vs synthetic oil

Doug is right about the zinc needed especially during engine break-in with a flat tappet cam. There is actually not enough zinc in any mineral-based oil now (aside from some of the diesel oils like Rotella) to protect a flat tappet cam. I spoke to Ford Racing about this after I bought my crate motor and they advised that I use cam break-in additive in whatever oil I run in that motor, forever, or at least until I switch to a roller cam (its a roller block with a flat tappet cam installed).
I ran mineral-based oil with Red Line's cam additive for my first year or so of driving (2500 miles or so), and now I run Red Line full synthetic. I called Red Line's tech line and they assured me that their synthetic oils contain the needed zinc for my cam. So far so good...

[Bronco95125]

Re: Mineral based oils vs synthetic oil

Thanks for the great info guy's.