Cummins Dry Exhaust Service Bulletin

[rlynch03]

Attached. Thought I would share this info I found on the Cummins Dry Exhaust Issues.

Has anyone went through each one of these steps? I didn’t consider the amount of air getting to manage load but it makes sense.

I believe the QSM 11 is well documented to have the same exhaust leaks in other manufactured boats. I doubt they all have poor air flow even if our models do.

 

[cod]

Good info........ Thanks.

 

[ttmott]

Very timely - Thanks.
I have my exhaust off see the pics. After indexing the manifold flanges they were out over 0.040 and a lot of pitting so I can see where my leaks were coming from. I set up the mill and trued the flange faces. All going back together with new bolt assemblies as recommended.

 

[Havana Shamrock]

When we bought our boat we had our manifolds milled and “new “ and improved gaskets installed and both leaked before the end of the season. No one has come up with a fix yet?
My cars have dry exhaust and have never leaked. Go figure

 

[techmitch]

When we bought our boat we had our manifolds milled and “new “ and improved gaskets installed and both leaked before the end of the season. No one has come up with a fix yet?
My cars have dry exhaust and have never leaked. Go figure

Hey Joe, the T.S.B. that rlynch03 posted originally came out 7/8/16 but was recently updated on 2/17/2020.
My bet is that if it was performed completely with the correct tools and the instructions strictly adhered to, the root cause would be found and the steps to rectify the problem could be identified.

 

[RBB]

We have always re torqued exhaust
Manifold bolts a couple times after operating the engine . This was on truck
Motors .

 

[ttmott]

We have always re torqued exhaust
Manifold bolts a couple times after operating the engine . This was on truck
Motors .

The issue is for our QSM11's the bolts cannot be accessed easily after installed and running. The exhaust, turbo, aftercooler, and complete cooling system has to be removed to get to those fasteners.

The primary reason for the leaks is due to the fuel burn at specific RPM's which is the load. The fix that most of us do is to take pitch out of the propellers to get our fuel burn numbers down at the operating RPM's. The result is a significant drop in EGT's and the consequential fix on the leaks.
Tom

 

[quality time]

We're tearing into this repair on my port engine next month since that leak is worse. The plan is to true up the flanges and reinstall with the current spec'd bolts and spacers. Have we determined that there is a newer gasket? If it holds then we'll tackle the STBD side next winter.

John (GimmeTime) worked closely with Cummins on his repair and I believe it has held after a few false starts, hopefully he will chime in here.

 

[rlynch03]

Hey Joe, the T.S.B. that rlynch03 posted originally came out 7/8/16 but was recently updated on 2/17/2020.
My bet is that if it was performed completely with the correct tools and the instructions strictly adhered to, the root cause would be found and the steps to rectify the problem could be identified.

Mitch
The TSB was printed 2/17/20 but the documented was published in 7/8/16. I am not aware of a revision to this TSB.

Attached is an Estimate from Cummins and they say they will perform the Cummins recommended check list for this repair. Cummins would not share the details of that checklist. I assume it is the TSB that I found...(smile)

What do you guys think of the costs? This estimate of course includes new Manifolds.

John (Gimme Time) - does this look similar to your estimate from Cummins? Did they Perform all of the TSB items checklists on your boat?

After everything I have read on this subject, from Seaboard Marine and forum boards I really do not think there is a one time fix for the inevitable leaking exhaust. I do believe we can manage and extend the life of the job though.

I have trimmed almost two inches of Pitch out of my Props, next I will clean the motors to determine if I am still leaking (once they start leaking I do not think they stop until re-seal is performed). I had planned to re-torque the Manifolds and other Exhaust fittings per the Cummins Manual but that may not be reasonable for the manifolds as Tom mentioned above.

The repair from Cummins is warrantied for one year, parts and labor. May have to define that further.

Below is Cummins bullet list scope of work.

"The total for the repairs will be $9,738.31.

We will remove all associated coolant lines that are in the way of getting the manifold off.

Removed the exhaust manifold.

Inspect the head for cracks, erosion, and or fretting.

Inspect the turbo mounting for any cracks or erosion.

Install new exhaust manifolds.

Install updated exhaust manifold gaskets.

Install updated exhaust manifold mounting bolts and spacers.

Inspect the air filters for reuse.

Perform a sea trial according to Cummins guidelines for this repair."

 

[quality time]

If that's for both engines I'd say it's in the ballpark of pricing I've heard. If they can't reuse the exhaust shields that will add a few thousand I believe. You may want to get a second quote from Art Cox at Anchor Bay East as he's apparently very familiar with this issue.

 

[techmitch]

2/17/2020 Updated Troubleshooting for Dry Exhaust Manifold Leaks for Marine


https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2016/tsb160069.html 1/7

Technical Service Bulletin

Technical Service Bulletin: TSB160069 Released Date: 08-Jul-2016

Updated Troubleshooting for Dry Exhaust Manifold Leaks for Marine

From my experience with "updated" T.S.B.'s this to me means that the troubleshooting/diagnostic procedure, parts and or sensor/thermocouple parameters have been changed.

As far as your estimate is concerned. It looks to me that they are going to perform the repair that you "requested" and says nothing about performing the T.S.B. to find the root cause. The T.S.B. may seem extensive and may also be quite costly but I believe that it is imperative to prevent future reoccurrence.

P.S. They also got the three C's wrong... Concern, Cause and Correction

"COMPLAINT


CAUSE

COVERAGE

SYMPTOMS:

EXHAUST LEAK WHERE MANIFOLD MEETS HEAD.

THIS ESTIMATE COVERS THE TIME TO TRAVEL TO AND FROM THE CUSTOMERS

LOCATION.

PLUS THE TIME AND PARTS TO COMPLETE CUSTOMER REQUESTED SERVICES.

ESTIMATE SUBJECT TO CHANGE UPON TEARDOWN AND INSPECTION.

CUSTOMER BILLABLE."

 

[ttmott]

Mitch
The TSB was printed 2/17/20 but the documented was published in 7/8/16. I am not aware of a revision to this TSB.

Attached is an Estimate from Cummins and they say they will perform the Cummins recommended check list for this repair. Cummins would not share the details of that checklist. I assume it is the TSB that I found...(smile)

What do you guys think of the costs? This estimate of course includes new Manifolds.

John (Gimme Time) - does this look similar to your estimate from Cummins? Did they Perform all of the TSB items checklists on your boat?

After everything I have read on this subject, from Seaboard Marine and forum boards I really do not think there is a one time fix for the inevitable leaking exhaust. I do believe we can manage and extend the life of the job though.

I have trimmed almost two inches of Pitch out of my Props, next I will clean the motors to determine if I am still leaking (once they start leaking I do not think they stop until re-seal is performed). I had planned to re-torque the Manifolds and other Exhaust fittings per the Cummins Manual but that may not be reasonable for the manifolds as Tom mentioned above.

The repair from Cummins is warrantied for one year, parts and labor. May have to define that further.

Below is Cummins bullet list scope of work.

"The total for the repairs will be $9,738.31.

We will remove all associated coolant lines that are in the way of getting the manifold off.

Removed the exhaust manifold.

Inspect the head for cracks, erosion, and or fretting.

Inspect the turbo mounting for any cracks or erosion.

Install new exhaust manifolds.

Install updated exhaust manifold gaskets.

Install updated exhaust manifold mounting bolts and spacers.

Inspect the air filters for reuse.

Perform a sea trial according to Cummins guidelines for this repair."

$2K of that is the manifolds alone.
There are a lot of soft goods that require replacement just to get to the manifold so you are probably around $500 in parts.
As a point of reference it took me two full days to tear the Port engine down and take off the exhaust manifold; that's me and the first time I've ever done this work. I think the Starboard engine will take somewhat longer.
Now the reason I'm doing this is the engines are due interval service of the coolers; so why not take care of the exhaust problems while in that deep....
Regardless, I would say that two technicians four days which includes testing to do the TSB.
If you are nearing the aftercooler maintenance interval - why not.

 

[rlynch03]

If that's for both engines I'd say it's in the ballpark of pricing I've heard. If they can't reuse the exhaust shields that will add a few thousand I believe. You may want to get a second quote from Art Cox at Anchor Bay East as he's apparently very familiar with this issue.

It is for both engines... I reached out to Bay Shore Marine (in our marina) for a quote. I will look up the two you mentioned, haven’t heard of them. I also like Stosh at Shore Power Solutions.

 

[Gimme Time]

Attached. Thought I would share this info I found on the Cummins Dry Exhaust Issues.

Has anyone went through each one of these steps? I didn’t consider the amount of air getting to manage load but it makes since.

I believe the QSM 11 is well documented to have the same exhaust leaks in other manufactured boats. I doubt they all have poor air flow even if our models do.

For some reason I can’t get the download to download or open so I’m just guessing about airflow. Cummins told me the engine room should never exceed 30 degrees of ambient air temperature. If you are getting warmer than that the engines room doesn’t have enough intake area. I’ve put a remote temperature sensor on the port engine intake filter which is furtherest of the two engines from intake opening. Since summer 2018 when I was told that I’ve monitored the temps and not got higher than 26 degree delta T so that says if all 52DBs are built the same that’s not an issue. I’ve run all over the Chesapeake Bay as well as to KW and have not see any I take air temperature issues FWIW.

Gimme Time II

 

[rlynch03]

My iPhone will not download that Service Bulletin pdf either. I have to use a computer to download it for some reason.

 

[ZZ13]

My iPhone will not download that Service Bulletin pdf either. I have to use a computer to download it for some reason.

After you push "Download" you are returned to the CSR page. On the top right you'll see a small blue down arrow with a circle around it. Tap on that to see the download.

 

[cod]

The issue is for our QSM11's the bolts cannot be accessed easily after installed and running. The exhaust, turbo, aftercooler, and complete cooling system has to be removed to get to those fasteners.

The primary reason for the leaks is due to the fuel burn at specific RPM's which is the load. The fix that most of us do is to take pitch out of the propellers to get our fuel burn numbers down at the operating RPM's. The result is a significant drop in EGT's and the consequential fix on the leaks.
Tom

Tom,
Curious of your thoughts of the bolt torque and if you will then torque the bolts to spec. of 42 ft-lbs. I did my port engine back in 2011 and as careful as I was putting everything back together, following torque pattern, etc. I made a mistake and over torqued the exhaust manifold bolts,(read the wrong number in the repair manual) only realizing it afterward. I expected issues but it’s 9 years later and almost 1,000 hours later and thankfully no issues. Now wonder if that mistake has served me well...... Thoughts
I’ve been procrastinating on the Starboard side but need to do it as well.
Just another point or recommendation.... Since the coolant needs to be drained for this repair, I first drained it and did a coolant flush with “Restore” before disassembly.

 

[Gimme Time]

Ok, time for me till spill what little I know but I don’t have the info with me. I’m in KW headed home for three days tomorrow. I’ll scan the info I have from Cummins which is the best way to provide it. I have t followed this thread in full and someone else. May have already provided the info.

I had Cummins factory owned service provider in Chesapeake, VA perform the recommended changes and modifications per the bulletin given me. It will be several days before I’m back and will post as soon as I can if not done by someone else before !

 

[ttmott]

Tom,
Curious of your thoughts of the bolt torque and if you will then torque the bolts to spec. of 42 ft-lbs. I did my port engine back in 2011 and as careful as I was putting everything back together, following torque pattern, etc. I made a mistake and over torqued the exhaust manifold bolts,(read the wrong number in the repair manual) only realizing it afterward. I expected issues but it’s 9 years later and almost 1,000 hours later and thankfully no issues. Now wonder if that mistake has served me well...... Thoughts
I’ve been procrastinating on the Starboard side but need to do it as well.
Just another point or recommendation.... Since the coolant needs to be drained for this repair, I first drained it and did a coolant flush with “Restore” before disassembly.

I talked to one of our structural engineers and got the bolting 101 class:
First "torqueing" a bolt is a very inaccurate means to tension a fastener due to variables in friction under the boat head, number of threads engaged, and variations in friction within the thread mating areas. However, due to the complexity and cost of measuring bolt stretch, rotational torqueing is the standard. Rotational Torqueing can vary up to 30% in actual tension (stretch) values. Most important is to chase and clean the threads and use the recommended lubricant.
Structures that use fasteners rely on the fastener clamping force for integrity. That clamping force is created by stretching the bolt within it's elastic material property range. As materials are put in tension they undergo four states: normal unstressed, elastic, plastic (yield), then fracture. In the elastic range the bolt length will return to it's normal unstressed state when loosened (consider it a spring). In the yield or "plastic" range the bolt will permanently deform its dimensional characteristics. Also, once a fastener is taken into it's yield range the tensile strength rapidly degrades. So, you can see that the fastener assembly needs to be in the elastic range to properly function and create that clamping force. Also notable is the higher strength the bolt is the more narrow the elastic range is. This goes to also say the longer the bolt grip (the unthreaded area between the head and threads) the greater the elastic range in length the fastener can go through.
The last part of bolting 101 is temperature - As a bolted assembly is heated each of the elements of that assembly expands and grows in size. The bolts will get longer consequently a reduction in clamping force can be realized should that length change remove the stress from the elastic range of the fastener material.
So, you might ask why the long tubes in the bolt assembly for the QSM11 exhaust manifolds and why the bulletin to get rid of the short tubes and use the long ones for all the fasteners? Well, you can now see that these are there to compensate the thermal expansion of the bolt material by increasing the elastic range of the material.
So, to your concern on "over torqueing" the bolts. The bolts have 10.9 stamped on the head which denote a high strength fastener and brings the concern of sensitivity with over torqueing and yielding the fastener. Usually, in high strength materials the yield range is so narrow that the bolt will fracture and snap right off or eventually fail due to a condition called stress corrosion cracking which is a time and environment based condition. As you neither have exhaust leaks nor broken bolts it appears you may still be in the elastic range, albeit the upper end of the range, and may be OK. However, if you start finding broken off bolts under the engine due to stress corrosion cracking over time then it's time to replace them. I would call it good and monitor.

Now you know how to build a watch.....
Tom

 

[cod]

Wow! Awesome response Tom. Thanks for taking the time for that detailed explanation. Broken bolts is exactly was I was expecting but hasn’t happened.
I believe according to Tony Athens on Boatdiesel, you can expect exhaust manifold gasket failure at approx. 1,000 hours if your typically running somewhere around 1900 rpms or above. So I’m somewhat expecting a failure soon since I’ve put that many hours on them since the gasket repair. I guess time will tell.....