08-20-2007, 08:03 AM
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Renegade Nuns on Wheels
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Join Date: Aug 2001
Location: columbus,
Oh
Cobra Make, Engine: Unique 427 roadster with 351C-4B
Posts: 5,129
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Not Ranked
This may add to the controversy: http://www.cranecams.com/pdf/548e.pdf
I don't recall exactly where I read about the changes in the hardening process but in a recent issue (although it was about roller cams) they talk about their carburizing process on cams taking them to 58-62 'c' on the rockwell scale. Plus they have recently released the Mikronite surface finishing process.
I used to run Mobil 1 5W-30 in my flat tappet motor in the Cobra... until I wiped a lobe. Then I found out about zinc and have been using Rotella T 5W-40 synthetic but with the new formulations, that may change as well. It has worked great but I have a note into Shell to find out was the new formulation is.
Of course, anyone could just add a bottle of Crane Breakin Lube at oil changes which has a high concentration of ZDDP. My understanding is that the GM EOS has been discontinued.
There are a number of oils with .11% of zinc or more (1100 ppm). This is the level I have most heard as the lower threshold. Buy the one you like and be happy!  |
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