[MODERATOR'S NOTE: There are mountains of opinions about motor oil in the archives, and more of those opinioins will not be posted in response to this message. Only responses that directly address the question of changes in additives for newer oils and the impact of the lack of these additives for our engines will be posted.] Group, Now that my DeLorean is almost fully restored, I've turned my attention to restoring a '68 Chevy. (Be patient, there is a DeLorean connection!). My mechanic just finished rebuilding the Chevy's engine and reinstalling it in the car. After the engine is broken in, he recommended I only use Pennzoil or Quaker State racing oil. Why? It appears the older blocks are not compatible with today's oils. In 1996, the API (American Petroleum Institute) mandated that motor oils used in production automobiles have less amounts of zinc and phosphorus to reduce pollutants. These are the main ingredients of the anti-wear additive ZDDP, zinc dialkyl dithiosphosphate. The above mentioned racing oils still contain high levels of ZDDP. Because they are marketed for "racing" engines, they do not have to meet new car motor oil regulations. The June issue of Hot Rod Magazine had an article about cam failures of older engines using modern oils. One cam manufacturer stated that cams made just 10 years ago would not pass today's quality standards. Apparently, older cams were made of softer material that heavily relied on ZDDP for long life. The article states "The zinc reacts with the cam lobe's surface. That creates a sacrificial chemical coating strong enough to keep parts separated to reduce the wear." This suggests today's synthetics without ZDDP will not protect as well as older oil formulations with ZDDP. A quick Google search on ZDDP seems to support what Hot Rod Magazine is saying. But, we all are aware of how things can be exaggerated by the press. Just to be on the safe side, my rebuilt Chevy engine will be lubricated with racing oil. For my DeLorean, I think I will switch to Shell Rotella T 15W-40 at the next oil change. Rotella was listed in the Hot Rod Magazine article as being a high ZDDP additive motor oil. The DeLorean manual lists 15W-40 as a recommended viscosity. Wal-Mart carries Rotella, so I should be set. Brian VIN# 4494 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/