I have a 6 cylinder turbocharged diesel engine that has been working
great for a year. Upon removing the head for a non-related issue, all
cylinder walls are good except for number 5 which has chunks/gouges
missing all around the top 1/4" of the cylinder wall. The chunks
don't currently effect the mating surfaces of the block to the head to
the extent that the engine will run improperly, except the thinness of
the mating surface in one area is excessive (about a dime thick).
There is no damage to the head.

Could these gouges be caused an excessively lean mixture in that one
cylinder causing detonation, and if so, could that be caused by a bad
injection pump or clogged injector?

Is the most likely cause of these gouges a broken valve that was
repaired before I took ownership of the engine, or something else?

Thanks for any help...

First of all:
All diesels detonate. All the time. Every power stoke.
Second:
It is very difficult to get a lean condition in most diesels, and a lean
condition actually LOWERS the combustion temperature, unlike a gasoline
engine. Less fuel = less heat produced.

As to what caused the damage to that cylinder, who knows....no way to tell.
Maybe a glow plug tip or injector tip broke off and rattled around, taking
out that piston and it was repaired cheaply to unload on the next person,
again, no way to tell.
What was the reason for pulling the head?
What else is going on with it?
Would be really nice if you posted some relevant info, like make and model
of engine, hours, etc.


"Michelle" wrote in message
om...
I have a 6 cylinder turbocharged diesel engine that has been working
great for a year. Upon removing the head for a non-related issue, all
cylinder walls are good except for number 5 which has chunks/gouges
missing all around the top 1/4" of the cylinder wall. The chunks
don't currently effect the mating surfaces of the block to the head to
the extent that the engine will run improperly, except the thinness of
the mating surface in one area is excessive (about a dime thick).
There is no damage to the head.

Could these gouges be caused an excessively lean mixture in that one
cylinder causing detonation, and if so, could that be caused by a bad
injection pump or clogged injector?

Is the most likely cause of these gouges a broken valve that was
repaired before I took ownership of the engine, or something else?

Thanks for any help...

The engine is a 2.5 liter '87 Mercedes turbodiesel. It has about
6,000 hours on it. The head was pulled due to a blown headgasket. It
had been running hot due to a blockage in the radiator, and eventually
it totally overheated blowing the gasket. The area where it blew out
on the headgasket was not on the cylinder with the gouges.




"bomar" wrote in message .. .
First of all:
All diesels detonate. All the time. Every power stoke.
Second:
It is very difficult to get a lean condition in most diesels, and a lean
condition actually LOWERS the combustion temperature, unlike a gasoline
engine. Less fuel = less heat produced.

As to what caused the damage to that cylinder, who knows....no way to tell.
Maybe a glow plug tip or injector tip broke off and rattled around, taking
out that piston and it was repaired cheaply to unload on the next person,
again, no way to tell.
What was the reason for pulling the head?
What else is going on with it?
Would be really nice if you posted some relevant info, like make and model
of engine, hours, etc.


"Michelle" wrote in message
om...
I have a 6 cylinder turbocharged diesel engine that has been working
great for a year. Upon removing the head for a non-related issue, all
cylinder walls are good except for number 5 which has chunks/gouges
missing all around the top 1/4" of the cylinder wall. The chunks
don't currently effect the mating surfaces of the block to the head to
the extent that the engine will run improperly, except the thinness of
the mating surface in one area is excessive (about a dime thick).
There is no damage to the head.

Could these gouges be caused an excessively lean mixture in that one
cylinder causing detonation, and if so, could that be caused by a bad
injection pump or clogged injector?

Is the most likely cause of these gouges a broken valve that was
repaired before I took ownership of the engine, or something else?

Thanks for any help...

In article ,
Michelle wrote:


I have a 6 cylinder turbocharged diesel engine that has been working
great for a year. Upon removing the head for a non-related issue, all
cylinder walls are good except for number 5 which has chunks/gouges
missing all around the top 1/4" of the cylinder wall. The chunks
don't currently effect the mating surfaces of the block to the head to
the extent that the engine will run improperly, except the thinness of
the mating surface in one area is excessive (about a dime thick).
There is no damage to the head.

Could these gouges be caused an excessively lean mixture in that one
cylinder causing detonation, and if so, could that be caused by a bad
injection pump or clogged injector?

Is the most likely cause of these gouges a broken valve that was
repaired before I took ownership of the engine, or something else?

Thanks for any help...

Diesels cannot "detonate" due to a lean mixture. Indeed, they always run
lean (except at full power)

A dropped valve, if there was one as you report, sounds like the probable
cause.

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