cam break-in

[MOPARHOUND!]

GM's E.O.S. (Engine Oil Supplement) for $4.95 (note the description/application):

http://www.sdpc2000.com/catalog/1016/products/584/GM-Engine-Oil-Suppliment-EOS-16oz-Bottle-.htm

Had a long drawn out post on the old site on this subject.  An oil guru on Moparts posted in a thread, where I gleaned most of my info.

Modern oils have zinc reduced, IIRC, to around 300 parts per million, racing oil around 600, whereas E.O.S. is like 5-6000 parts per million.

The bottle labeling is GM's "speakeasy" way of keeping the EPA happy.  Supplement or Break-In Lube?.....Hmmmm........

I used the entire bottle on break-in of my last cam, and use a half bottle at oil changes.  Do them myself so I don't mind a few dollars for the insurance, especially since my last two cams died (one with 0 miles, and one with 9800 miles).

[doechsle]

 The zinc is supposed to be harmful to catyletic (spell check) converters. This is one of the reasons it was mandated to be removed from pass. car oils. This may also shed light on why the GM bottle says not to use it every oil change. My car has no converter.

[Ghoste]

The common roller lifters today make it less needed as well.