VK56 Engine Teardown

12:18 the pan is full of crud. There are 3 rod bearings spun. This engine simply died from abuse and lack of maintenance.

I have seen different oil analsysis on VQ40's that show pretty good shear at not very high mileage use. I think most engines with long complex timing chains and valve trains are generally hard on shear. I agree with shorter OCI's, but I have a feeling in this case it was 20K miles on speedy lube oil and filter plus hard driving.
If they were Blackstone, it's often fuel dilution and not shear (since they don't actually measure fuel).
 
I've posted on this subject many times and often get dismissive comments with respect to my position on varnish.

The reality is, as @wwillson alluded to with respect to the carbonaceous material in the ring lands, if you have varnish where you CAN see, you have a lot worse where you CAN'T.

That is, if the head(s) and valvetrain have managed to accumulate deposits, this means that the additive package of the oil has been overwhelmed. The dispersants and detergents are no longer able to do their job and so the materials they are tasked with holding in suspension through the mitigation of agglomeration and prevention of laying down, hit a saturation point and they plate-out. This is varnish.

Now, if you think it's bad seeing this showing up in these areas of moderate heat and reasonable flow, it's significantly worse in the ring pack where flow is extremely low and the conditions are the harshest.

Now, @aquariuscsm said that varnish is the precursor to sludge. That's only partially correct. Sludge and varnish are comprised of most of the same materials, but varnish doesn't necessarily lead to sludge and sludge doesn't typically lead to varnish. But you can have both happening in the same engine.

I've posted this chart before:
SludgeVarnish.JPG


You can see that resins plating out leads to varnish. Varnish + carbon, water and solids can lead to sludge. But so can just those resins + carbon, water and solids. Varnish requires heat, sludge does not. If you have heat, you probably don't have water, which is why you end up with varnish instead of sludge.

These resins + soot can form silty deposits (often improperly referred to as sludge), or, they can form a thick dark varnish (heavy varnish) called lacquer.

It's easy to figure out what gets deposited in the ring land area, based on this data.

When liberated, it looks like this in your oil filter:
motorcraft10.jpg


@wwilson has more examples.
 
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