Cummins QSC 8.3 L

[Mark Gacka]

I have a Cummins QSC 8.3 L engine which was purchased with a new boat in May 2016. All Cummins recommended maintenance was performed by an authorized Cummins dealer in April 2017 with 214 Hours on the engine. Yesterday I took the boat out and as soon as put power to the engine it was sluggish and billowing black smoke from the exhaust. The engine has 281 hours on it currently. I found a 12 inch crack in the aftercooler housing causing a significant boost leak. There was no evidence of fluid leakage or contamination.

I am assuming that this particular cast aluminum housing was bad or out of specification. Is there something else that can cause the aftercooler housing to crack? I never had any alarms, or had any engine temperatures/pressures been abnormal. I also run the boat 100 to 200 RPM below Cruise or

Topic

[Philip]

Mark

Half the battle has been won in that you now know how to service your engine! And that knowledge will give you many many hours and years of solid Cummins life. Service those aftercoolers and go boating. And for giggles you can do some oil samples and watch the sodium and wear metals decline.

As to convincing Cummins otherwise, don’t bother – “Couch Engineer”, “Head in the sand”, whatever you want to call it, you now know more than that fancy desk engineer and the Cummins trained tech combined.

Phil

[Mark Gacka]

Blow By Test

Yesterday the Cummins dealer completed the blow by test. The highest reading we had was 2.5 inches of water at WOT. (Topped out at 3055 RPM) A 7.67 mm orifice was used. If I have done the math correctly that would give up a 66 liter/minute flow rate.

In my opinion, Cummins should must be proactive in correcting their design flaws in their aftercooler. When you pay top dollar for a new boat with a new engine, you should not have service the aftercooler prior to starting the engine for the first time. It should not fail within 18 months of use (or 23 months of marine age.).

Both the dealer and Cummins were very reluctant to investigate if salt water was ingested into the engine. If I had not done the oil analysis both the dealer and Cummins would have insisted that the engine had not ingested salt water.

The only way I got Cummins attention was demand an explanation from them why the Sodium and Wear metals were so high in the oil analysis. In addition, I scheduled the additional work on the engine, at my cost, to find out if the Sodium could have gotten into the oil from any other source. Only then, did they pay attention to the issue.
The way they acted gave me the indication they were hiding from something and running away from the true problem.

I will have the aftercooler serviced every two years or possibly more frequently going forward. This is truly a weak link in the engineering of the power plant and is relatively cheap and easy to fix on Cummins behalf.

I wonder why they don’t fix this engineering problem?

[Tony Athens]

Let me add this your list of “vernacular (if that is the right word) of things” you may want to remember……. You cannot under prop an engine like this, you can only over prop it………….

Tony

[Mark Gacka]

Max 2900 RPM’s

Another reason why I want to proceed with the test is the following:

As this is a new boat I always knew that I would have to tune the prop sometime within the first two years to prevent overloading of the engine. Once every two months I run the boat at WOT to make sure I can get a minimum of 3000 RPM out of the engine. I also ran proper fuel burn curves ( and speed curves) comparing these to Cummins specs and the Back Cove performance curves. All of this was done when I had at least 90% fuel and water if not more. Everything was fine, and the worst WOT I ever read was 2990 RPM. The last WOT test was performed about a month before the aftercooler failure and I got 3010 RPM.

Just prior to the aftercooler failure, we added some things for longer distance cruising. Please remember that this is single screw boat and at cruise and higher RPM’s the boat will list to the port due to Prop torque. I had stored all the heavier items on the starboard side of the boat and as far forward as possible to help compensate for the torque. When my wife added the items she wanted for long distance cruising a month prior to the failure (only about 150 lbs) it caused me to store things in a much diffent locations on the boat. As a results I have to use more down trim overall and heavier starboard down trim than I did in the past.

During the sea trial of the aftercooler replacement I noted I could only get 2900 RPM. Within a few days I took the boat out and ran proper fuel burn and speed curves at 200 RPM increments. ( I am not hung up on speed, I just want to make sure I am not overloading the engine.). The results show that I am over propped. I have the boat scheduled to be pulled on December 11 for bottom paint and assuming there is nothing causing additional drag on the bottom (and the diver that cleans the bottom once every 4-5 weeks assures me there nothing on the bottom or running gear causing drag) I will have the prop redone.

I now have agreement from my wife she does not need anything else on the boat for long distance trips and everything stored in the best location on the boat for balance vs where I can fit it. I am making the assumption that reduction in WOT RPM and the increase in fuel burn is caused by the change in The weight distribution and the drag caused by the trim tab settings now being used.

I just want to make sure the engine is not having an issue and do want to mask the issue by making a prop adjustment.

I hope this all makes sense. I would rather be under propped than overloading the engine. My need for speed left me 10 years ago.

Mark Gacka

[Mark Gacka]

I am going to go ahead with the tests. They are not that expensive and my only concern is, will I have a major problem in the future because of this incident? I probably will not, but the blow by test also gives me a point of reference for the future.

This is the smallest cruising boat I have owned and it is the first single engine boat I have owned. It makes me nervous with this incident to take the boat to some of the more remote islands in the Bahamas I like to visit.

We live in the Cape Coral Ft Myers area on the West Coast of Florida. It is great boating and fishing down here (I have a fishing boat also:28 ft Aquasport.). You can up the intercostal north, or run outside to Tampa (130 nm),or in the Gulf , South (125 nm) to Key West.

It is a great place to live if you enjoy boating.

Thanks again

Mark Gacka

[Tony Athens]

Personally, now that you have indicated that the engine starts and runs as new, I’d go fishing and drop the rest……………………Your call..

Where are you in Florida?

Tony

[Mark Gacka]

Additional Tests

I will have the tests completed by November 28th.

I forgot to reply regarding looking at the exhaust side of the turbo. My initial thought regarding the subject was that this area may show corrosion if the misting was very heavy and for a long period of time. I normally visually inspect the Turbos every year on my boats. (Both the exhaust and compressor side.) I had planned to start this routine at year 2 or 500 Hours as the boat is new. Even if the blow by test is OK, I may start the Turbo inspection routine earlier tha originally planned.

[Mark Gacka]

Tony:

This makes me feel much better about the situation. My biggest concern was long term corrosion issues and the resulting future failures. I will get the pressure and blow by tests arranged, but this may take a few weeks because of my travel schedule and the upcoming holiday.

Our current ambient morning temperatures are 60 degrees Fahrenheit. That is about as cold as it gets. We may have a few nights in the 50’s and even fewer as cold as 45. (Southern Florida). The boat still starts perfectly and never misses a beat. The boat is running fine and comes-up on plane in the same manner as the day I took it from the dealers dock. All 6 cylinders sound crisp at start.

I am frustrated with the dealer and Cummins. I had asked about the blow by test the day the aftercooler was changed. The answer was,” it would be a waste of time. “ If I had not insisted on the oil sample, Cummins and the dealer would still be insisting no salt water got into the engine.

I don’t know if Cummins will help or not. I have asked Cummins for their reasons why they believe that corrosion and abnormal wear in the combustion chamber have not occurred due to this incident. So far there has no response. If they don’t contact me in another 2 days, I will contact them.

I will get the tests done you recommend and will get back you. It just may take a bit of time.

Thanks for all the help.

Mark Gacka

[Tony Athens]

Mark,

Let’s put the Oil Analysis aside for the time being..

Since you are worried about any contingency damage to the engine that may be related to the salt water “misting” into the combustion chambers, let’s try a more practical approach to looking at this..

1– can we pressure test the aftercooler now at 20-25PSI on the air side for 24 hours to insure that is is not leaking now?

2– Can we do a proper “blow-by” Test?

3– After sitting at the dock for 2-3 days, how does the engine start up? What is you ambient temp right now at night?

Regardless on the Na PPM in the oil, with as many oil changes that you have done and the quality of oil these days, if your engines start “like new”, ( with good batteries, solid battery connections to insure 200+++ starting RPM, 2-3 rotations is normal and then all six should hit solid and be crisp at 45-50F block temp ) the blow-by is within factory specs, your aftercooler is no longer misting, then from the outside looking in, I would not worry..

But for sure, it’s obvious you are not happy with how all of this all has gone. Will Cummins do anything to help? Don’t know ..

As I said, just trying to make you look at the situation from a more practical stand point.. FYI, I know for a fact these engine can tolerate a lot of misting over time and not show and signs internal wear from it..

If you are concerned about the exhaust, let me see some pics.. If not right, then we need to look inside the exhaust side outlet of the turbo.

Tony

[Mark Gacka]

Oil Analysis

Please see the attached oil analysis I promised to send from the previous post.

Mark Gacka

[Mark Gacka]

The Issues Continue

I would like to take this opportunity to thank all of you for all the help you gave me via postings on this website. A few weeks ago I posted pictures of a Cummins aftercooler that had approximately a 12 inch crack in the housing. The aftercooler failed within 18 months of purchasing the boat new and 24 months of marine age on the housing. (It failed well within the original engine warranty period.)

The advice and recommendations that every one gave me on this site were excellent. I have implemented everything you recommended and the aftercooler will be serviced at a minimum of every 24 months in the future to your protocol. (It is a shame Cummins cannot get this issue corrected. When you buy a brand new boat, you would think that the aftercooler could last through the warranty period.) I have also worked out a solution for fresh water flushing the system for my circumstances.

When the dealer replaced the aftercooler I had a chance to inspected the failed unit and posted pictures on your website. I truly believe that the engine had been sucking in seawater for quite some time. The tech kept telling me that he did not believe that the engine saw any seawater. After the sea trial, I insisted that the dealer pull an oil sample and send it out for analysis.

I have always done oil samples, but I only use them as a tool over a long period of time to help head off big problems. I insisted on one at this time because I was concerned that we would have high sodium and potassium levels with no glycol detected. In other words, the engine ingested seawater due to the seal failing on the aftercooler. (The o ring and little bit of grease they use on the aftercooler is a poor design and has no safety margin. Once you see it for yourself, it is easy to see why this a weak part of the cooling system.)

The oil and the filters had been changed twice since I owned the boat. Once at 51 hours ( 4 months) and again at 209 hours (11 months.) The attached oil sample was taken when the boat at 285 hours (16 months.) (Cummins recommended oil was used in all oil changes and performed by an authorized dealer.) Once I saw the oil analysis, I told the dealer to do a complete PM on the engine and generator.

The sodium content is off the charts. I have now made contact directly with Cummins and have told them the aftercooler was replaced under warranty, but the engine may have been damaged because of salt water being ingested. The responses I having been getting back is “change the oil and we will resample in 50 hours and everything will be fine.” This is not acceptable to me.

The engine could have been sucking saltwater for 5 hours, or more likely 200hrs+, based on what I have seen.

One of the things I thought about doing to check for additional damage, short of getting into the internals of the engine, is examining the exhaust side of the turbo and see if there is evidence of damage caused by salt water.

I would appreciate other opinions if examining the exhaust side of the Turbo would be worth while, or if there is anything else I can examine to look for potential damage short of pulling the engine apart? I have asked Cummins (service desk) the same question and received no response.

I may change Cummins dealers. I am not asking them to do any of this work for free or under warranty. I am willing to pay them to do the work. However, I am tired of the approach of “lets wait until in breaks and then we will fix it,” approach. I have told both Cummins and the dealer that the aftercooler has been replaced, but that there are additional issues to deal with because it appears that saltwater got inside the engine.

Again, thanks for all your help. It has and will be greatly appreciated.

The Oil Analysis is to large of a file to post at this time:

The Highlight are:

NA 658 PPM
K 29 PPM
AL 214 (Based on the corrosion on the housing surprised that this is not higher)
CU 64 PPM
CR 11 PPM
FE 214 PPM

I will rescan the report at a resolution and try to post the file in a few minutes.

Mark Gacka

[Rob Schepis]

Ah, I was close, but yes my bad – I just reread the thread, she’s a single screw, for some reason I was thinking twin screw. I should have went all-inclusive with “North End Composites” .. I’m sure she’s a beauty

[Mark Gacka]

Rob:

Close, but the boat is manufactured by the sister company, Back Cove. I considered the Sabre, but I will not buy a boat with the POD’s. They are maintenance nightmares, especially in salt.

Mark Gacka

[Rob Schepis]

Tony Athens wrote:

…..
Go fishing…..

I am thinking this is a “no fish allowed” boat.

My three “indicators” for guessing the type/builder are: (1) the boat name, (2) twin screw powerplant, and (3) she was built in Maine – leads me to think Sabre???

[Tony Athens]

Mark,

The QSC 8.3 has shown to be a rock solid engine as long as you understand how to deal with the “weak points”–The aftercooler being the biggest weak link.. I watch over plenty of them with well over 5000 hours and at least one pair in the 15000 hours range with never a head pulled..

The raw water pump for this engine has has been very good..

Go fishing, learn how to fresh water flush your engines, maybe install a 250W oil pan heater , look at your prop curve for the model you have and be sure your CRUISING RPM vs, Fuel burn are not over the “prop demand curve ( lower line) and worry much much less..

Tony

[Mark Gacka]

QSC 8.3 L Aftercooler

Tony:

The after cooler was taken off the boat and lubed per your protocol. The lube used was what was recommended “Alco Metalube.” You have been very helpful and I believe what you are saying about the after cooler. I don’t understand why cummins is so difficult about this issue.

Being relatively new to Cummins Diesels I was hoping you could answer one other question for me. I had planned to service the after cooler at 22 month or 500 hours of usage, whichever comes first. (I know this is odd timing, but I always did my annual maintenance on 11 month cycle, or if I used the boat a lot in a given time frame I never let the service go longer than the recommended hours by the manufacturer. )

Is servicing the after cooler, return fuel, and oil transmission cooler every 22 month or 500 hours or whatever occurs first, adequate for this engine, or should it be done more frequently? I am big believer in preventative maintenance, but at the same time I do not want to tearing things apart every six months. Zincs are naturally done much more frequently.

I am used to the mechanical diesels and have boated for 40 years with one break down while underway besides this one. That was a transmission and we never did determine the cause. Everything else was caught and repaired when servicing the boat(s) ,

This engine worries me because it is a very small package capable of producing 600 hp. I don’t run it hard and don’t use all the HP, but I would prefer when the manufacturer increases the HP out of the engine, they would make the engine bigger and heavier. I worry that the engine is going to require very frequent servicing if the boat is used about 250 hours per year at a 45% cycle rate, but I want to do the proper amount of preventative maintenance, not just what Cummins says in the book.

I also know that the raw water pumps are not what I consider to be reliable and I inspect them for leaks frequently, but that is a different story for another time.

Thanks again for all the help.

Mark Gacka

[Tony Athens]

Mark,

Just three comments on this post..

1) Pic 571 tell me hands down that saltwater sat inside that aftercoolers seawater side at the “scum level” for many many months without movement

2) Cummins and their school trained “techs” has their head in the sand as to how to properly assemble a “mixed metal” aftercooler on this general type of design..

3) As to all the rest, we probably will never know for sure, but does that really matter when we know how it should be done?

Tony

[Rob Schepis]

This may very well be one of those times that “It’s better to beg for forgiveness than to ask for permission.”.

[Chris Dahl]

My warranty was not voided by greasing up the AC at 40 hours. You might simply lean on your local Cummins guy with some common sense narrative and see if it gets you a reprieve from their warranty threat. You really do want to take that simple extra step of disassembly and grease up when brand new.

1 user thanked author for this post.

Corey Schmidt

[Corey Schmidt]

Freshwater flush

If you want to protect that expensive engine component in the short run until after your warranty expires then I would suggest you implement some sort of fresh water flush system on that boat to prevent the inevitable corrosion that will occur in that short time frame…

Aftercooler Disasters

[Author]

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