I couple of days ago I wrote about my oil and I computed the amount of wear metals in it. Well, I computed it for only Aluminum.

Now, I do it with gusto! Here’s everything in my oil!

Units

Amount

Density

Weight

Volume

Sphere

Element

PPM

g/cm^3

g

mm^3

mm (dia)

Al

7

2.7

0.0249

9.2099

2.6007

Cr

1

7.19

0.0036

0.4941

0.9808

Fe

14

7.874

0.0497

6.3162

2.2934

Cu

10

8.96

0.0355

3.9647

1.9637

Pb

5

11.34

0.0178

1.5663

1.4409

Sn

2

5.769

0.0071

1.2315

1.3299

Mo

53

10.28

0.1883

18.3149

3.2704

Ni

1

8.908

0.0036

0.3988

0.9132

Mn

1

7.21

0.0036

0.4927

0.9799

Ag

0

10.49

0.0000

0.0000

0.0000

Ti

0

4.506

0.0000

0.0000

0.0000

K

0

0.862

0.0000

0.0000

0.0000

B

3

2.08

0.0107

5.1237

2.1389

Si

8

2.3290

0.0284

12.2023

2.8564

Na

153

0.968

0.5435

561.4847

10.2356

Ca

2566

1.55

9.1155

5880.9409

22.3949

Mg

13

1.738

0.0462

26.5715

3.7023

P

879

1.823

3.1226

1712.8687

14.8448

Zn

966

7.14

3.4316

480.6188

9.7185

Ba

0

3.51

0.0000

0.0000

0.0000

I added the last column since it’s easier to imagine a little ball of some stuff than the volume in mm^3. Micro liters aren’t something that most of us have really wrapped out heads around.

The wear metals are the first group up until nickel (Ni) skipping molybdenum (Mo) . Each of these comes from some part of the engine itself. The Aluminum comes from the pistons and the case. Chromium from the piston rings. Iron from the crank shaft, con rods and the valve train. Lead, tin and copper from the plain bearings. Nickel, for my engines at least, comes mainly from the cylinder lining.

The rest of the elements are additives to the oil itself. Molybdenum is added as a high-pressure lubricant if the oil film breaks down and you get metal-on-metal contact for instance. Zinc and phosphorus are similar anti-wear additives. Calcium and magnesium are added as detergents and dispersants. Can can read more about oil chemistry from a couple of different sites, BobIsTheOilGuy.com and Blackstone Labs among others.

I did the math for the sum of the wear metals as well: the volume is 23.18 mm^3 or a sphere 3.54mm in diameter weighing 0.142g. (It’s a tad bigger than 1/8″ in imperial)

It’s creepy thinking that my engine “lost” a chunk of metal that you can really wrap your head around.

Sure it’s not really that much, but it’s something that is feel-able.

At this point I’m not worried about this at all. It’s a new engine still and this is the material that gets knocked off as it breaks in. The real interesting part is going to be after the next oil change and seeing how the numbers change!