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Cracked pistons
- Thread starter 93detroit
- Start date
ak diesel driver
6.5 driver
OEM pistons?
93detroit
Well-Known Member
Yes, thinking '06 n/a Optimizer pistons are not treated.
dbrannon79
I'm getting there!
Were you getting any blow by or oil smoking from the tail pipe?
93detroit
Well-Known Member
None
Will L.
Well-Known Member
I have seen this before. I have suspicions of it’s cause but never proven.
It is not super common but does occur. I think:
Heat is the cause- 99.9% sure of that.
I believe this is from bad injector spraying un-misted fuel through the precup opening onto the piston. When there is the talk of bad injector burning a hole in the piston - this is on it’s way to becoming a hole.
Other possibilities is too advanced timing. high egt. Not enough oil spraying bottom of piston. Too hot of fuel (similar to gasoline mixed in.
Notice this is the thinnest part of the piston. And where the flame front starts. So it is the most susceptible part.
Test injectors becomes first diagnostic.
Looking in the cylinder walls for more piston slap to have occurred is an indication of timing advanced being a factor.
Checking exhaust valves and seats for cracking is indicating high egt.
Look at bottom of piston for scorching.
Drill motor the oil pump to see proper oil from squirters - a bucket to hold oil and see with pan off means face under the engine, so just before end of day and a shower is recommended.
Fixes on some is obvious- good injectors, fix oiling, adjust timing, etc.
really what to do in a rebuild- coating. Good thermal coating helps fight this off even if it is bad injectors which is worse case scenario. Won’t stop it- but longer engine life is the song we sing.
It is not super common but does occur. I think:
Heat is the cause- 99.9% sure of that.
I believe this is from bad injector spraying un-misted fuel through the precup opening onto the piston. When there is the talk of bad injector burning a hole in the piston - this is on it’s way to becoming a hole.
Other possibilities is too advanced timing. high egt. Not enough oil spraying bottom of piston. Too hot of fuel (similar to gasoline mixed in.
Notice this is the thinnest part of the piston. And where the flame front starts. So it is the most susceptible part.
Test injectors becomes first diagnostic.
Looking in the cylinder walls for more piston slap to have occurred is an indication of timing advanced being a factor.
Checking exhaust valves and seats for cracking is indicating high egt.
Look at bottom of piston for scorching.
Drill motor the oil pump to see proper oil from squirters - a bucket to hold oil and see with pan off means face under the engine, so just before end of day and a shower is recommended.
Fixes on some is obvious- good injectors, fix oiling, adjust timing, etc.
really what to do in a rebuild- coating. Good thermal coating helps fight this off even if it is bad injectors which is worse case scenario. Won’t stop it- but longer engine life is the song we sing.