Since I basically rebuilt my motor on my R56 n12 Cooper and still waiting for my 4 new pistons from the UK ( a week to go) I was wondering should I use synthetic oil to break in the new pistons or would it even matter? I have been using Castrol synthetic as long as I owned her, about 3 years now.

 

I would. Remember, the oil is lubricating all parts of the engine, not just the new rings.

 

So true, just thought I heard someone say (not on here) that synthetic oil shouldn't be use to break in a new motor. (I know mine is not new) but just thought there was a special blend I should use. Thanks! I just want her back and running without any more trouble. I guess my mind is working overtime.

 

The factory fill is synthetic so I suspect that it's safe. I guess the process to follow the new engine break in procedure is more important. Nice and easy with varying loads and RPM's for the first 500 to 1,000 miles is what I recall.

 

Car Is delivered with syenthic oil....so factory good enough for a factory new motor...
But do what your rebulder tells you to do.

 

Thanks for the info.
Much appreciated!

 

ZippyNH gave good advice. Follow your engine builders recommendations. Cylinder composition, finish and ring alloy make a difference. My builder recommended conventional oil for the first 500 miles then 1000 to 1500 on synthetic followed by regular change intervals.

If they don't do it as standard ask them to install a magnetic drain plug. Fresh engines make metal. Doesn't matter if it's new or overhauled it will make metal. I've seen it in everything from piston to jet engines. The magnetic plug helps prevent it from circulating and can alert you to a problem if it starts making metal later on down the road.