Hey all I have my 85 22re (factory 22re) that was rebuilt from top to bottom. I really want to run royal purple In it but have heard mixed results as to how long the break in period is and whether u can run synthetic during the break in period or not. My girl has about 4 k on the new engine running 10-40 conventional and had her break in oil change at about 500 miles in . When can I start running the really good stuff without hurting anything ?

 

After several thousand miles, any oil should be fine.
If the cylinders have been properly surfaced, (generally a little coarser is better than too fine a grit when honing) Almost all cylinder/ring break-in has been done in a couple hundred miles, most of that even in the first 20 to 50 miles.

It is my experence that when new rings fail to seat, the problem can usually be traced back to a cylinder hone job that was not agressive enough to cut the rings in before the sharp edges of the honed surface were destroyed. Most of this happens right away.

Your engine should be well broken in by now.

 

Ok thank you so much I've been hearing some high numbers and was just curious the truck is my baby and I don't Wana wreck it