Zinc is not missing...there is a little less of it, so you might want to change the oil every 3000 miles instead of every 5000 miles. The engine only needs a little tiny bit of zinc at a time.
What??? It has nothing to do with how often you change oil. The ZDDP does not get "used up" with increased milage. It has to be there in the first place.
The problem today is there's only one or two companies building all the flat tappet hydraulic lifters, so you can buy from almost anyone, and it will be the same lifters. But the biggest issue I found with hydraulic flat tappet lifters is those ****py wire clips they all use today! I've had two engines that lost those clips while racing, and had lifters come apart, ending my day, and had to tear the engines down to retrieve the pieces, and replace lifters. In looking for a better lifter I got told they're all the same, over and over. I asked why nobody used internal C clips as the lifters used to have, and the answer was always cost. What a crock! How much do those internal C clips cost anyway? Well I decided to find out what they cost, and if I could buy them to replace the wire clips. IN searching sources I found them from as little as $.75 cents each to a few dollars each. After measuring the size I needed, I ordered a few dozen, so I could swap both my SBC and BBC lifters to internal C clips. I used my small arbor press to compress the lifter, and replace the clips. Took a few seconds per lifter, and the big work was just removing them from my engine. Since I swapped to internal C clips I've never had another lifter come apart. You'd think the cam or lifter makers would offer this option, and they could buy large quan***ies of C clips for much less than we'd pay? I'll never put a set of flat tappet lifters in a engine again without swapping out those cheap wire clips first.
Yes it does. Zinc in the form of ZDDP is a self-sacrificing additive that plates out on the wear surfaces of moving parts in a very thin layer, forming a gl*** like film. No matter how much zinc is in the oil that film will only develop so thick, and once that maximum thickness is achieved it will not develop any thicker no matter how much zinc is in the oil. As the zinc is activated and forms that sacrificial layer it undergoes a physical change. As it is worn off the moving parts due to wear it has done it's job and is no longer able to provide any protection; but as the thickness of the film is reduced additional zinc in the oil will replace that which has worn off, and thus maintain the thickness of the film, until there is no longer any non-activated zinc left in the oil, at which time the only remedy is to drain the oil and replace with fresh oil.
The Jalopy Journal
