Flat tappet cam life

[zrayr]

Originally Posted by rdorman

The new formulation of Rotella T 15W-40 that meets the CJ-4 spec contains 1210 ppm zinc, the max allowed for CJ-4. If I recall correctly, it used to be about 1400. 1210 is plenty.

http://www.machinerylubrication.com/...up=Lubrication

It is my understanding the companies like Crane and Comp Cams have changed hardening processes in respoonse to lower phospated ash/zddp.

that's good news from the cam manufacturers. Do you have a web page, or other source available for posting, so we can get the whole story?

thanks,

Z. Ray

[rdorman]

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!

[rdorman]

From ED, a chemist at Shell:

"Shell Rotella T Multigrade Oils in the API CJ-4 formulations contain approximately 1200 ppm zinc. This is down slightly from the typical 1400 ppm zinc found in the previous API CI-4 Plus formulation. However, in critical applications, such as gasoline engines with flat tappets, push rods, etc., we believe the new formulations still have enough zinc to provide adequate protection. In diesel engines, the new formulations gave the best protection from wear ever seen in the Shell Rotella T Multigrade product line."

[rdorman]

I also asked Ed specifically about the 5W-40 rotella T synthetic that I currently use. Here is his reponse:

"Shell Rotella T Synthetic Oil has not yet been reformulated for API CJ-4, though we expect to release the reformulation in the next couple of months. At the current time, Shell Rotella T Synthetic Oil SAE 5W-40, in the API CI-4 Plus/SL formulation, contains approximately 1600 ppm, or 0.16%, zinc."