Flat tappet cam life

[zrayr]

Originally Posted by 4pipes

Ray, synthetics are not recommended for FE's with flat tappet cams. It's a separate problem than ring sealing. Crane cams states on their website that synthetics may be too slippery for the lifters to rotate adequately in their guides (not enough friction between the lifter and the cam), and that if the cars are not started regularly, the oil will drain off the cam faster than conventional oils.

Facts are in short supply in this discussion. Without comprehensive scientific research they always will be. What we are left with is direct real life experience, and hear-say. Neither of which is a broad proof of fact.

No cam manufacturer, no oil company, and no engine builder are going to admit fault. They will point elsewhere, to the other factors, as Crane does with "maybes" and other vague references. With flat tappet engines declining in numbers, the importance of this issue to be scientifically researched is also on the wane. We are left to determine what works on a case by case basis. There will never be a scientifically proven, definitive yes or no on the use of synthetic oil in flat tappet engines of differing designs. All one can do is observe what works for them, and make decisions accordingly.

I have experience with Ford small block, and the FE series of engines that have used synthetic oils in racing and street applications, over a period of years, without the problems others have encountered. So using a oil with superior wear characteristics make sense for me. If others have had a negative experience when using synthetic oils, they may decide the problem was causes by a lubrication issue, and go back to a conventional oil.

Cams and lifters have been failing for years before synthetic oil were introduced. So it seems unlikely that all current failures can be ascribed to the use of synthetic oil.

Z. Ray

[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.

[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."