Lucas Response To Zinc Additive

Hold on a sec, let's not swallow this sales pitch from Lucas quite so enthusiastically. Maybe it's just me, but I have a hard time trusting technical information from someone who doesn't know how to spell a simple, easy word like Zinc. There's no "k" in it. I lose even more confidence when the genius from Lucas doesn't know the difference between "ware" and "wear". :roll:

But this isn't English class, so let's focus on the science of what we're trying to do here. 5200ppm is many times greater Zn concentration than needed, and more is not better. It's been well documented that a 0.10% to 0.12% concentration of Zn and P is optimal for flat-tappet engines, for example in SAE papers 770087, 831760, and 2004-01-2986 (these papers were published in 1977, 1983, and 2004, respectively, so the recommendation is not reduced for compliance with the latest super ultra low emission vehicle requirements).But, that data's old, and there's newer information that the ZDDP scare is even more exaggerated than the unleaded-gasoline scare or the Freon-12 scare: there is plenty of life after all three.

If you have determined to use a ZDDP additive anyhow, a whole bottle would be massive, huge overkill and a needless waste of money, not to mention the likelihood of screwing up the chemistry engineered into the motor oil —*take a look around; every time a petrochemist is asked about additives, they practically beg and plead with the public not to add anything because it usually doesn't help and it quite often makes things worse.

The Lucas rep states that a whole bottle of their magical moose milk should be used at each oil change to bring a 5-quart system to 5200ppm Zn. The moose milk comes in a 16oz bottle, which means if the Lucas rep is telling the truth*, the additive itself contains 39,600ppm Zn, or about 4%.

Here's the math: we're running ½qt (16oz) of Lucas moose milk plus 5qt of engine oil. That's 16 ounces of moose milk and 144 ounces of engine oil, or 11.1% moose milk and 88.9% engine oil. The engine oil by itself contains about 800ppm Zn, so we subtract 800 from 5200 and get 4400 coming from the 16 ounces of moose milk. 4400 divided by 11.1% gives us 39,600ppm (or 0.6336 oz) of Zn in a 16oz bottle of moose milk.

What we want to wind up with is between 1000ppm and 1200ppm of Zn in our crankcase, so let's say we want 1100ppm, or 0.11%. There's already 0.08% Zn in a quart of the latest SM engine oil (actually, most of them run a little on the high side, as it seems, but we'll use the 800 figure). In 5 quarts of SM engine oil, therefore, you've got 0.128 ounce of Zn. Therefore, you're a little under 0.05 ounce short of what you want.

You're holding in your hand a bottle of moose milk containing 0.6336 oz of Zn. That means you are holding a bottle containing just over twelve and a half doses of Zn. You would need to add just 1.25 oz of moose milk to a 5-quart fill of SM engine oil to have the optimal 1100ppm of Zn. That's 2.5 Tablespoons, folks, not a whole bottle!

* - Whether the Lucas rep is telling the truth is an open question. The company is known to make false claims which, if followed, will damage your engine. Link goes to a demonstration on bobistheoilguy.com , widely regarded as the go-to place for knowledge about engine oil and relatied matters.