Metal shavings - do they normally exist inside an engine?

JAG

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5,320
Location
Fredericksburg, VA
I've used a magnet inside the oil filter in my 1.8T for most of its life (at 56k miles now) except during break-in. Every oil change, I clean off the metal particles which are about same size as the diameter of a hair (a few microns likely). Under a microscope they look like shiny metal spheres. I've never found anything bigger than that which I'd call a "shaving" (which I'd define as a highly visible chunk of metal. I agree that if shavings are coming off the engine, something is wrong. I doubt shavings are being produced during break-in in a healthy engine, but expect that the micronic sized particles I've seen later are more prevalent at this time.
 

Kestas

Staff member
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13,942
Location
The Motor City
Any high-volume product with acres of machined surfaces will have contaminants. Some people obsess too much over this. I work for the bearing industry and part of my job is to find and identify contaminants. You would expect a bearing to be exceptionally clean with no contaminants..... that is not the case! If a production bearing has contaminants, what do you think an engine has? As a side note, some products have an increased amount of contaminants than in the past. Some of this is the result of the cleaning agent 1,1,1-trichloroethylene being phased out of plants. Now things are being washed with soap and water, which is only dumped when absolutely necessary. Diameter of a hair is roughly 75 microns.
 
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1,027
Location
East Helena, Montana
Its my understanding that today's engines are so well cleaned at the factory before the vehicles are shipped that there's little or no manufacturing shavings, bits, or other residue left in them, unlike the old days. Now, on a rebuilt engine, it may well be different and one should expect such particles and use break-in oil and oil filter changes accordingly.
 

Kestas

Staff member
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13,942
Location
The Motor City
During production, bearing balls are usually rotated between two abrasive discs, with each subsequent disc a finer abrasive, until the final size and finish is reached.
 
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4,478
Location
Southern California
quote:
Originally posted by Bamaro: With so many aluminum blocks now, there should be very little metal to be attracted to a magnet.
Very astute observation, but apparently you're unaware of ferrous metal crankshafts, chrome-plated iron piston rings, ferrous metal cam lobes, and ferous metal cylinder sleeves? Chrome and iron are both strongly influenced by magnetic fields. My car has an engine built with an aluminum cylinder block and aluminum heads. My "Super-Plug" magnetic drain plug traps a small, but visible amount of metallic crud at each oil change, and it obviously isn't aluminum. Opinion only, but I suspect this crud consists of chrome and iron containing particulates which are too small to be trapped by the oil filter. Nevertheless, I'd still rather have them out of circulation to whatever extent is possible.
 
Messages
328
Location
San Diego, CA
Ray H, have you noticed any erosion of the magnet metal over time on your SuperPlug? Seems I remember that someone here reported that their magnetic drain plug suffered size losses over time...that can't be too good. Cheap insurance if you ask me!
 
Messages
5,069
Location
Saratoga, NY
Do an oil change on a new Briggs & Stratton or Tecumseh engine (without an oil filter) after it has run 3-5 hours. You'll see plenty of metal shavings from break-in. [Freak] --- Bror Jace
 
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40,604
Location
Great Lakes
The subject has been discussed in the past, while talking about magnetic drain plugs or magnets inside oil filters, presumably designed to trap metal shavings. But my question is, in a properly functioning engine, should there even be any such metal shavings, large enough that they would have to be trapped by a magnet? I mean, having any kind of visible metal shavings would lead me to believe, there is something seriously wrong with the engine. Do those shavings only occur during break-in? Are todays' modern engines really breaking in by producing sizeable shavings?
 
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7,775
Location
Oklahoma
The only time I've ever noticed metal shavings were on my '88 Justy. Dealer said that this was normal and just some of the residue left over from manufacturing process. Guess he was right because I never had any problems with it.
 
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1,967
Location
Kitsap, WA
Timing chain and gears seem to throw off a lot of metal. Converted one motor to a belt drive and the reduction in hair on the magnet was very noticable.
 
Messages
3,161
Location
North Arkansas
Do oil changes at my business. ANY magnetized drain plug is gonna have material stuck to it. Dont' believe it passes through filter. When it's washed into oil pan It's too heavy for oil flow to hold suspended (IMO). Bob
 
Messages
1,910
Location
Vista, CA
If you're chasing particles, the thing to worry about is the trend. If the amount stays the same over time, or worse, grows, then it's important to take note. If the amount decreases, over several oil changes, then don't worry.
 
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