I read an article in Vintage Truck about how the oil companies are reducing substantially the zinc dykial dithiophosphate which helps premature cam lifter wear on flat tappet lifters and recommended use of the diesel oils which still carry higher zinc levels than current car oils. Would running 15W-40 be a problem such as Chevron Delos for my 272? It was just rebuilt and has 300 miles on it.

 

I've heard the same thing about the reduced zinc . Alot of engine builders are breaking engines in on the diesel oil, as a matter of fact I'm fixing to change over to the Chevron 15-40, I'm running a 351w. I can't see where it would hurt anything.

 

There is also a delo 10w30 you can buy if the weight bothers you.

 

The article also mentioned about adding the GM's camshaft and lifter prelube 12345501 at every oil change because it mentioned that even the diesel oils will be reducing the zinc additive eventually because of the new 2007 model engine standards.

 

Many engine rebuilders and Y-block people have suggested running "diesel" rated oils such as Delo, Shell Rotella, and other 15w40 oils. Other companies such as Comp, Crane and other cam grinders have also suggested using diesel type oils in addition to zddp additives etc.

I'll be running Shell Rotella 5W40 syn in my 292 after I break it in.

There is a fear out there in radio land that the diesel oils are losing or getting serious reductions in zddp levels to comply with newer specs on diesel oils for newer after-treated engines.

I suppose that may be a problem. Most newer engines nowadays have roller followers and probably don't need high pressure wear inhibitors needed to lube "regular" flat tappets.

In view of that we may have to use a "snake oil" additive that claims to replace the zddp or add a special secret sauce flat-tappet wear reducer.

I think we're probably fine for a few more years if we use a diesel oil that meets the older spec instead of the newer spec.

Go to Crane, Comp, or other cam manufacturers site and do what they suggest for break-in and use one of their additives or one they suggest for flat-tappet cam life.

I think I would stay away from Slick-50 or other "snake oil" additives and marketing ploys.

This subject has been beat to death. do a search and you'll spend all your waking hours reading about it!

Cheers,


Rick