This article about bubble physics has something to do with diesel engines.

greasytshirt

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What parts can degrade if vacuum bubbles form on the surface then explosively collapse? Hint: They see huge shock, causing high frequency vibration. Not all diesel engines have the item in question, but almost all large ones do.
 
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Turtle

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Well, I would say it's where the coolant meets the cylinder walls, which can cause cavitation, but you threw me by saying not all diesel engines have them.
 

truckblue

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What parts can degrade if vacuum bubbles form on the surface then explosively collapse? Hint: They see huge shock, causing high frequency vibration. Not all diesel engines have the item in question, but almost all large ones do.

i'll take an uneducated guess...Injectors?
 

greasytshirt

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i'll take an uneducated guess...Injectors?
Nope.
Well, I would say it's where the coolant meets the cylinder walls, which can cause cavitation, but you threw me by saying not all diesel engines have them.
It's liner cavitation, specifically. There are a few cases of some engines that have parent bore blocks with cavitation pitting issues, but they are relatively uncommon.

A wet liner will absolutely get eaten away. Holes right through the liner, or the liner separates into two pieces right at the top.
 
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greasytshirt

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When the liner sees the shock of combustion, it essentially rings like a bell. This high frequency vibration causes bubbles of vacuum, cavitation, on the liner's surface. When the bubbles collapse, the shock is tremendous. Metal is eroded away.

This is the reason we use coolant with SCA's and other types of coolant for diesels rather than the old green stuff. Special coolant additives bond to the liner surface, providing protection against cavitation. Coolant under pressure (radiator caps) also helps reduce the formation of cavitation pitting.

I pulled apart a John Deere diesel that had been running just water. Pitting was excessive up and down the thrust surfaces, around the top of the liner, and around the bottom circumference. The engine smoked, had low compression and power.
 
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blackpup

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Regarding the liners in the class 8 engines, their purpose is to make a rebuild of that engine possible, due to cavitation effects on cylinder walls ? or just cheaper, ?
 

greasytshirt

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Regarding the liners in the class 8 engines, their purpose is to make a rebuild of that engine possible, due to cavitation effects on cylinder walls ? or just cheaper, ?
It makes rebuilds much, much easier. The engine can stay in the truck. It is NOT cheaper to do it this way. Not all engines with removable liners have liners in direct contact with water, but many do.

To rebuild an engine with a parent bore block, the engine would have to be removed, disassembled completely, bored, honed, etc. Or if the cylinder walls are too thin to support overboring, they can sometimes be sleeved. This machine work can sometimes be done by a mobile machinist, but the expense is considerable.

To rebuild an engine with removable liners, the head and oil pan are removed, the pistons and rods are pushed through the top, then the liners are pulled out from the top. New liners are pressed in from the top, usually with hand tools. You can literally do this in your backyard.
 
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blackpup

Veteran Expediter
Started to say that I had pulled the liner on a Mack 300 , then I remembered that I just pulled the piston, valve punched a hole in the top of piston, due to some one trying make an R model Mack with a 300 hp 5 speed tranny run 85 MPH . One piston and several cylinder heads later that some one realized that this idea might not be a good one.
jimmy
 
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greasytshirt

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Mechanic
Started to say that I had pulled the liner on a Mack 300 , then I remembered that I just pulled the piston, valve punched a hole in the top of cylinder, due to some one trying make an R model Mack with a 300 hp 5 speed tranny run 85 MPH . One piston and several cylinder heads later that some one realized that this idea might not be a good one.
jimmy
Sounds like an expensive lesson.
 
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