valve seat ring

[ktblogistics]

it is 6.7 isb cummins and truck had bad valve seat ring on cylinder 3, head has been replaced and after 3k miles same thing happened on cylinder 4 , any thoughts on this ? truck is demandeted,(new head from cummins) not reman

[ktblogistics]

pictures

[tree98]

Who did the demandate? Does it still have the VG turbo on it? Can you post a pic of the tops of the pistons?

[Rawze]

(11-24-2024 )ktblogistics Wrote:  it is 6.7 isb cummins and truck had bad valve seat ring on cylinder 3, head has been replaced and after 3k miles same thing happened on cylinder 4 , any thoughts on this ? truck is demandeted,(new head from cummins) not reman

take your pick...

== Exhaust wet-stacking can cause valve seat(s) to loosen.

== A Fuel source introduced into the cylinder when it is not supposed to be (leaky injector, leaking valve stem, oil or fuel getting into the intake, etc).

== excessive cylinder/manifold pressures can cause it (bad programming and/or excessive boost all the time). Is it known to have a turbo cough (a whoof, whoof, whoof sound under the hood) when you get on it hard or let off the full throttle suddenly?.

== Uneven head heating/overheating.

---------

- See the scoring and odd coloring vs the other cylinders around the intake valve(s)?. Looks to me like Fuel (or something) is getting into that cylinder when it should not be.

Did it pass a rail leak test after the rebuild??...
ref: http://rawze.com/forums/showthread.php?t...3#pid75483


Its also de-mandated, so if I have not reviewed the programming, then that is the next step as well.

[ktblogistics]

i have only this one for now , will try to get more,

[Rawze]

(11-26-2024 )ktblogistics Wrote:  i have only this one for now , will try to get more,

(just from looking at the photos and speculation) ...

Looks like BOTH of the valves were held open when they should not have been.

With all the fuel scoring in the cylinder.. it looks like fuel (or something highly combustible) got in there when it was not supposed to be. maybe excessive amounts of starting fluid? or something else?.



Perhaps Also slipped cam? as both valves made an imprint, not just the one that did not shut all the way.

Is that even an OEM piston?.
also, in the photo of the piston, it looks somewhat like injection timing was too high and possibly the spray pattern was outside the bowl. = Have the programming checked out to see if timing was set excessive.