Flat tappet lifter failure

[Alan Roehrich]

Originally Posted by Barry Polley

In listening I also heard the oil additives we are buying for extended wear capability is not even close to what the oil chemists used in the oil we are using. My guess is regulations won’t allow it.

True. Oil is not what it used to be.





This isn't directed at Barry, but rather just general information that racers really need to know.


Way too many people are trying to play "home chemist" by "brewing up" their own additive packages. It simply doesn't work. There's only so much of any additive that will even stay in suspension. Excess moly-disulfide and ZDDP not only won't even stay in suspension, but they will clog your oil filter, they will accumulate in the bottom of your oil pan and restrict the pick up, and worse still, they'll actually cause the damage you're trying to prevent. Beyond a certain concentration, ZDDP and moly-disulfide will literally cause flat tappet failure.


If you're dealing with these problems, and you want to know what's actually going on, for oil, seek a real tribologist, like Lake Speed Jr.


People also need to understand that certain base materials are not an ideal mix. You can't just buy a camshaft and assume you can by just any lifter and they'll work together.And certain coatings are far more dangerous than they are helpful.


I refuse to use DLC, for the simple reason that you cannot trust it. Not ever DLC will work on any camshaft. No DLC will run against cast iron. Not just anly DLC will adhere to every material. And you can't assume any DLC will work with any oil, some have severe reactions to certain base oils and additive packages. Some companies applying DLC are not necessarily that trustworthy either. They want to sell you their coating. But they don't all necessarily want to make sure that everything you have will work together.



Believe it or not, the old Shubeck lifter, properly cared for, is far less hazardous to your engine than many DLC coated lifters. The problem is, we can't find anyone interested in manufacturing them.


There are certain surface treatments we are looking at. But it's a delicate balance. You have to maintain a surface that will create and sustain an oil film, or it will never survive. And you have to spin the lifter.