Knocking noise after rebuild.

[0759]

07 5.9, 180k had to rebuild. After picking up truck I here slight knock which last until oil psi builds and up to 2100 rpm. Been going back n forth with builder. Oil analysis shows a level of 36 for chromium at 3000 miles after rebuild. Builder put in a gallon of Lucas, noise quited down and more prevelant after engine as at temp for a while. Second test showed chromium at 7 both had high silicone. Noise is driving me insane. I drained Lucas out noise got louder. Also installed fluiddamper, other noises went away this one did not. Any guidance? Builder says he will stand behind if failure occurrs but believes noise is natural occurring combustion noise. I am not buying. If you have not installed fluiddamper do so.

 

[Tuesdak]

Why did you have to do a rebuild?

There are reasons to go with a OEM Cummins 6.7 fluid type damper over a Fluiddamper...

Try and get a video of the noise posted on youtube and link here.

 

[0759]

Why did you have to do a rebuild? Thanks for reply. Hate to admit, #6 had broken rings, started using oil. Never wiped stick when I checked it. Lost oil psi, started knocking rod shut off quick. Needed a crank, #6 rod and piston. All were used parts, #6 had scratch but honed within spec.rebuilt head, new injectors, am told all diagnostic checks are normal, blow by, comp, overhead. Also took out dual mass and installed new single clutch.

There are reasons to go with a OEM Cummins 6.7 fluid type damper over a Fluiddamper...

Try and get a video of the noise posted on youtube and link here.[/ I will get a video and post.QUOTE]

 

[RVTRKN]

SMF's can have NVH transmitted through the Trans when at or below 1500, maybe along shot but could it be NVH?

 

[0759]

SMF's can have NVH transmitted through the Trans when at or below 1500, maybe along shot but could it be NVH?[/ Sorry bro SMF? NVH? QUOTE]

 

[Bob4x4]

noise vibration harshness

 

[0759]

So that noise would come from what? It is loudest underneath the truck. They also said removing the heavier dual mass might be the cause. Other question, is the high chromium levels from break in and usual?

 

[RVTRKN]

I never thought of the heavier DMF (Dual Mass Flywheel) dampening the noise in the Engine as well as the transmission. I guess it's possible, if the SMF (Single Mass Flywheel) is lighter. The only way to know would be to swap back to the DMF.

 

[Motorhead]

I would like to know what kind of an engine builder would pour a GALLON of LUCAS, Honey thick additive into a new engine? What that tells me is that the LUCAS goop increased the viscosity of the oil and would naturally quiet excessive clearances and make the engine sound better.

 

[sag2]

Buy a cap off tool and cap one (or buy two and do two at a time) injector off on each cold start. You might be able to narrow it down to a cylinder if it gets quiet on start up. Silicon is dirt or sand material and should be very low with clean oil and clean engine parts.

 

[0759]

https://youtu.be/EsjXCXpC9LI

 

[0759]

I only considered it because we had a 7.3 excursion. Long story/short but took dampening device off of truck vibration went away but heard a lot more engine noise...

 

[0759]

I would like to know what kind of an engine builder would pour a GALLON of LUCAS, Honey thick additive into a new engine? What that tells me is that the LUCAS goop increased the viscosity of the oil and would naturally quiet excessive clearances and make the engine sound better.

I know, that is my thoughts. If the sound is affected by oil, then it has to be a clearance issue. This morning it was quiet and normal until it warmed up. What are your thoughts on the high chromium levels?

 

[Motorhead]

High chromium levels could be from new rings seating. sag2 has a very good diagnostic idea for you to try. It will isolate each cylinder from getting any injected fuel thus quieting any noise in that particular cylinder.

 

[0759]

Buy a cap off tool and cap one (or buy two and do two at a time) injector off on each cold start. You might be able to narrow it down to a cylinder if it gets quiet on start up. Silicon is dirt or sand material and should be very low with clean oil and clean engine parts.[you can not hear the noise on cold startup, it has to get warm. Does that make any sense?]

 

[Tuesdak]

Silicone means you check the air intake. Open engine will have high silicone. Gasket in a tube, used on some rebuilds, will spike your oil samples for a long time. The wear metals should come down and silicone alone is just gasket material. Silicone, iron, and other ring wear is a air leak in the intake.

The video needs to be made not private.