Cylinder liner fracture
Cylinder liner fracture
(OP)
In 3200HP diesel engine we have recurrent failure of cylinder liners. They fracture in the angle between the body and the settlement zone. We think the failure is related with deformations in the settlement zone in the engine block so we will grind this surface and also the upper part of the bore in the block. Does anybody have known this kind of failures and its causes?.





RE: Cylinder liner fracture
If you have too much piston skirt to bore clearance, I suppose the piston could be knocking too hard against the lower section of the bore when it changes direction after BDC.
We haven't had that problem, yet, so these were just a couple of thoughts.
RE: Cylinder liner fracture
RE: Cylinder liner fracture
What engine is this?
Could post some pictures or a drawing of the problem with some details of liner thickness etc etc.
Are they wet or dry sleeve arrangement etc.
How are the liners being finished to size,when installed or other.
Is there any other obvious problems associated with this, piston scoring etc etc.
Do you know what grade the sleeve material is ?
Is it the same sleeve failing.?
Do the big end bearings or the small ends show any signs of premature wear along with the sleeve failures?
Is the engine operating under full load conditions all the time or does it vary.?
RE: Cylinder liner fracture
RE: Cylinder liner fracture
Is this the same cylinder you are having problems with low compression.
You said it may be block distortion, how is this engine mounted, is it mounted on vibration dampers, rubber some how or is it solidly mounted,
RE: Cylinder liner fracture
The engine is mounted on conventional foam, like in most constructions.
RE: Cylinder liner fracture
Upper area?
Lower area?
Sounds like liner clearance is excessive, and or piston loading?
RE: Cylinder liner fracture
RE: Cylinder liner fracture
The best fix for the counter bore area is to sleeve it.
Also check manufactures spec on diameters of both upper and lower bores in the block.
RE: Cylinder liner fracture
RE: Cylinder liner fracture
Another question, in the upper zone of the bore according to the manufacturer specifications we have a clearance between 7 and 12 mils in diameter. Making a calculation of thermal expansion of the liner it would expand around 13 mils. In the engine design the liner could be "tight"in this zone???. It is important because we want to know if it is possible to install an "oversize" liner (a liner with a bigger diameter in the upper zone of the bore in the block).
RE: Cylinder liner fracture
Everything expands together. That is the block will expand too.
Have never experimented with it. But I have never liked the idea of any liner clearance. Allows for too much loading and vibration, and helps contribute to cavitation pitting on the lower portion of the liner and the block. Dry liners are pretty much zero clearance, semi press fit. And never seems to be an expansion or cracking problem.
If it is possible to install the L-ring. Then it should also be possible to bore that portion of the cylinder block to accept the larger liners. Of course maintain the manufactures recommended clearances. I would guess the cracking problem is from excessive clearances, that would cause loading due to that calculated thermal stress, and or a vibratory situation, make sure all the manufactures dimensions are checked for all areas that the liner locates in.