Engine Break-in

When I do my race engines, I run them through several cycles - up to a certain temp, cool it off, then do it again. I start out at lower temps for the first couple of cycles to make sure my file-fitted rings don't get too hot and butt before broke-in all the way. (I try to be extra cautious.) Another step, which was a pain until I switched to composite lifters, was to break in the cam with OEM or much lower pressure valve springs than the cam needs, not going too high with the rpms. (Extra insurance.) But rpms should be varied to help splash the oil around to different degrees.

Some diesel oils still have some zinc, but it's hard to keep up with the ever changing formulas unless it actuals gives that info on the bottle. Usually, when recommended for 2007 & newer trucks, it has a lot less. Break-in additive is a good idea if not using oil specifically made for break-in. Afterwards, use a proven/known high zinc oil and you won't need the extra additive. Personally, I use & recommend Amsoil products. They have their own break-n oil and a wide variety of regular high zinc oils to cover any application that needs it.

Amsoil high zinc options.
[ame]http://www.amsoil.com/techservicesbulletin/MotorOil/TSB%20MO-2007-08-08%20Flat%20Tappet.pdf[/ame]

Amsoil break-in oil:
http://www.amsoil.com/shop/by-produ...ak-in-oil-(sae-30)/?page=/storefront/brk.aspx