Crower is the cam maker that says "no" to synthetics. I called the Crower factory, and spoke to one of the cam designers. Named Bill IIRC.
Bill said that the steep lobes of the high performance cams had definitely shown greater wear in their own tests.
To believe that the Crower folks are "full of it," you must believe that they A) do not know their own products, and B) did not properly test their products. Some of you here will believe just that, but I think it's safe to say that Crower may be on the right track.
Remember, too, that many of the race engines which survive for hours on the tracks on synthetic oils are not necessarily running these huge duration, steep lobed cams. So they do not stand as testament to the virtues of syns in all applications. And these engines will likely be rebuilt after one or two races, so such matters probably wouldn't come to light anyway.
One design of a diesel engine may be less dependent on barrier additives than another. For instance a Cummins ISX might show less cam wear on a syn than say a Caterpillar C-12 would, or a Mercedes, etc.
I think when the jury finally comes in, we'll all come to realize that there is indeed a relationship between reduced EP ability and synthetic base oils. Some engines will never miss this loss of barrier protection by virtue of their design--
but others will. Whether it will be ultimately blamed on the syn's unique chemistry crowding out the ZDDP layer or whatever--it seems to be generally true that most syns show more valve train wear than dinos do (search the used oil analysis here and you'll see what I mean. Type in "because" and "cleaning" and you'll find the used oil analysis I'm referring to.
). In most cases, the elevated iron isn't bad enough to worry about. But given the case of extreme pressure components, we may find that some synthetics may not protect as well as typical dinos do.
Dan
