If you don't already know, the amount of zinc and phosphorus in todays oil has been drastically reduced, and is most likely causing flat tappet lifters to flatten cam lobes.

Here are some links about it.

http://www.revsearch.com/dynamometer...lattappet.html

http://www.powerandperformancenews.c...APNV2I10.htm#1

 

"Use a good racing synthetic like Amsoil 20W-50 Series 2000."

That's all you need to know. . .

 

That's been said since the last reformulations. Not really 'new' and I'm pretty sure it's been mentioned a few times recently as well. That's why a lot of us have been using delvac and rotella for break ins and then the delvac 1 and rotella T, Amsoil or Mobil 1 after break-in.

 

It came up in the mid-80's even, with German Ford overhead cam 4-cyls. The Europeans didn't have the additive restrictions, designed the cams assuming the zinc was there, Ford paid for a bunch of engines before they figured it out. I know AMSOIL put more zinc in their 5W-30 at the time, although I haven't heard any issues lately. Of course, almost all OEMs are roller lifters, now.

 

SO we can use any oil with the GM EOS every oil change and be fine? Just asking because I still have 4 cases of 10w30 pennzoil in my garage.

 

GM EOS is magic stuff. One of the few "additives" that really does something helpful for your motor. Highly recommend for break in. Good to use even after break-in.

 

Or use the Crane or Comp Cams break in additive for the break in period.

 

I read on BITOG that Valvoline Synpower Oil Treatment also has a great add package.

Alternately, use Synthetic or Diesel oils.