One happy dude...Cummins related.

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Baker

Baker

TF Site Team/Forum Founder
Site Team
Joined
Oct 1, 2007
Messages
7,331
Location
Texas
Vessel Name
Floatsome & Jetsome
Vessel Make
Meridian 411
For those that don't know and have after cooled Cummins engines, the after coolers are the life and death of those engines. They should be serviced at least once every forum years and some would argue more often...every two years. Lets just say 2-4 years. I just bought a boat that is 12 years old with no evidence of the after coolers being serviced....also luckily, no evidence of damage caused by a failing after cooler. New ones cost in the $2500 range and times two, that can be some money. But I budgeted for worst case scenario.
The Cummins tech took them apart and while they were dirty and pretty clogged up with crap, they were structurally sound. They were able to clean them up and got them back on the boat. They are supposed to be sending pics of the job but haven't received them yet.

So a $5000 swing in my favor!!!! I am a happy dude!!!! Propellers are the next question mark. Should know the answer by tomorrow!!!

And if you own after cooled Cummins engines, do not ignorantly look away from your after coolers. If they leak, saltwater goes directly into the intake of the engine!
 
I hope your lucky streak continues. If the props are OK, more money available for electronics, right?
 
Good news that saves you five boat bucks is always welcome news. Way to go!!!
 
We had our aftercooler serviced last year, The yard made some sort of mod to it so that it drains or can be drained (gotta revisit that).
 
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The cold water in the aftercooler condenses inside when the engine is running "easy" or at idle and the drain is to be able to let that water out after shutdown. I thik that's a Cummins sanctioned modification.
 
It is my understanding that the condensate drain that Cummins added was the result of litigation. Tony Athens, the Cummins guru on boatdiesel, believes that the drain is useless. He says that any condensate is perfectly clean and will be blown through and burned with no harm to the engine.

David
 
Five Boat Bucks buys a lot of beer! That is a good thing!
 
djmarchand said:
He says that any condensate is perfectly clean and will be blown through and burned with no harm to the engine.
Click to expand...

It's not the water that gets "blown through" that is a problem. It's the water that can collect in low spots and cause corrosion damage. In the worst case scenario, a slug of water can cause thermal shock damage to an intake valve, breaking it off and destroying the engine.

The water that collects is far from clean. The same soot and sulfuric acid compounds that accumulate to block and corrode the surfaces of the cooler concentrate in the condensation that can pool in the charge air passages.

A drain is hardly a waste of time and money.
 
RickB said:
The water that collects is far from clean. The same soot and sulfuric acid compounds that accumulate to block and corrode the surfaces of the cooler concentrate in the condensation that can pool in the charge air passages.
A drain is hardly a waste of time and money.
Click to expand...

Condensation = distilled water
Soot, acid in exhaust yes; aftercooler no.
 
Brooksie said:
Condensation = distilled water
Soot, acid in exhaust yes; aftercooler no.
Click to expand...

If that were the case, no one would ever have to clean the airside of an aftercooler, would they?

What do you think that nasty stuff is that collects on the airside of the tubes enough to eventually block the air flow? Where does your crankcase vent to? What is in the blowby that comes out your crankcase vent?
 
Whiskey? Also, I frequently clean up "condensate" spills from the oil fields. Most mimic gasoline and diesel in chemical composition...
 
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I have read that the drain is "minimally effective".
I was knowledgeable of this issue when I did my repower of my ex, the old Mainship I. I chose the 270 hp version of the 6BTA because it was "jacket water aftercooled" meaning antifreeze cooled. Yes the aftercooler was less efficient hence the "only" 270 rating but it was also virtually maintenance free as far as the aftercooler was concerned. It also smoked less at idle because the air charge was not being supercooled.
I also chose to vent my crancase into a container that did not allow it to be sucked back into the engine so my intake system would stay clean. That is easy and cheap to do.
 
dwhatty said:
We had our aftercooler serviced last year.
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I stopped by the Cummins dealer to see what they thought of Baker's post. They agreed with it and I'm scheduled for an after cooler service next week.
 
I'd sure like to know what is entailed in aftercooler service. I have a Cummins QSB 5.9. Can someone enlighten me? Is this something I can do? So far, all I have done is renew the pencil zinc once a year. Thanks.

Ron
 
I was alerted by one of the Cummins mechanics in my area to be careful to seal the aluminum housing well from the nickel alloy cooler so you don't end up with a lot of corrosion in just a few months. When originally made the painted coating on the aluminum does that pretty well but tends to pull off and leave bare metal after disassembly.
 
windmist said:
I'd sure like to know what is entailed in aftercooler service. I have a Cummins QSB 5.9. Can someone enlighten me? Is this something I can do? So far, all I have done is renew the pencil zinc once a year. Thanks.

Ron
Click to expand...

If you do some reading on www.boatdiesel.com you'll learn what you need to do. There are lots of threads about it.
 
SeaHorse II said:
I stopped by the Cummins dealer to see what they thought of Baker's post. They agreed with it and I'm scheduled for an after cooler service next week.
Click to expand...

Glad I could get you moving, Walt. You have known my disdain(for lack of a better word) for Cummins engines and ultimately the reason for that disdain is the premature failure of these engines. The reason for that premature failure is that people do not service these after coolers. They begin to leak and then you end up with saltwater in your charge air....ie your intake!!!!! That is not a good thing and it will cause bad things as you could imagine. The 6BT is a great engine at its core as has been proven on the road and in other applications. It will ingest saltwater with great aplomb...it just cant do it for a long period of time....as you would imagine. I ultimately had to join boatdiesel.com so I could get some expert counsel on what is up with these engines so that I could sleep at night after purchasing a Cummins powered boat. And also so I could relax while boating instead of worrying about the next $30k puff of white smoke that may issue from the exhaust at any minute. I am being a bit melodramatic here...to make a point!!!

I would highly recommend joining boatdiesel to anyone that operates after cooled cummins engines. It is only $25 a year. I also caution you that it is people with problems that are posting so you don't exactly get a warm and fuzzy feeling about your engines while you are on there...just a heads up. But you can learn from others mistakes and learn a lot from the gurus on there.
 
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windmist said:
I'd sure like to know what is entailed in aftercooler service. I have a Cummins QSB 5.9. Can someone enlighten me? Is this something I can do? So far, all I have done is renew the pencil zinc once a year. Thanks.

Ron
Click to expand...

I would imagine the QSBs are similar to the Bs except electronically controlled. Like the above poster said, you can learn eu thing you need to know on boatdiesel.con. I do not know if you can glean the information you are looking for without joining. But $25 is pretty cheap. Also, I don't know where you are and your proximity to a Certified Cummins tech, but the going rate to service these things seems to be about $350-500 per engine. That is awfully cheap insurance and peace of mind considering there is a lot of other **** on a boat that can cost you a lot more. One boat buck over 2-4 years ain't bad when you are maintaining the heart of your boat!

I think Timjet on here does his own...maybe he will chime in...
 
windmist said:
I'd sure like to know what is entailed in aftercooler service. I have a Cummins QSB 5.9. Can someone enlighten me? Is this something I can do? So far, all I have done is renew the pencil zinc once a year. Thanks.

Ron
Click to expand...

Cummins engines are very easy to work on; you can do all needed services with minimal drama.

boatdiesel has all the info you need.
Aftercooler Maintenance - Cummins
 
Baker said:
Glad I could get you moving, Walt. You have known my disdain(for lack of a better word) for Cummins engines and ultimately the reason for that disdain is the premature failure of these engines. The reason for that premature failure is that people do not service these after coolers. They begin to leak and then you end up with saltwater in your charge air....ie your intake!!!!! That is not a good thing and it will cause bad things as you could imagine. The 6BT is a great engine at its core as has been proven on the road and in other applications. It will ingest saltwater with great aplomb...it just cant do it for a long period of time....as you would imagine. I ultimately had to join boatdiesel.com so I could get some expert counsel on what is up with these engines so that I could sleep at night after purchasing a Cummins powered boat. And also so I could relax while boating instead of worrying about the next $30k puff of white smoke that may issue from the exhaust at any minute. I am being a bit melodramatic here...to make a point!!!

I would highly recommend joining boatdiesel to anyone that operates after cooled cummins engines. It is only $25 a year. I also caution you that it is people with problems that are posting so you don't exactly get a warm and fuzzy feeling about your engines while you are on there...just a heads up. But you can learn from others mistakes and learn a lot from the gurus on there.
Click to expand...

Your concerns along with their shortened lifespan due to over propping was the main reason I bought a boat that was a repower candidate.

That way I know the engines history and am less likely to receive a visit from mr big bill
 
ksanders said:
Your concerns along with their shortened lifespan due to over propping was the main reason I bought a boat that was a repower candidate.

That way I know the engines history and am less likely to receive a visit from mr big bill
Click to expand...

Yessir!!! Over propping is also their enemy...and the enemy of any high strung recreational marine diesel. Under prop them a little and they will last forever.

The boat/engines I bought have only 350 hours on them. "Marine age" is always a concern but not much damage can be done from over propping in that period of time. Also, the engine survey showed no symptoms of damage due to these concerns. I will be getting new props and be basically shooting in the dark on the pitch. It left the factory with 23x28 and Timjet said his boat was over propped at 23x27. So I am gonna go with 24 pitch. He is gonna go with 22. His boat is VERY similar to mine(Carver 355) with the same engines. I think we will be in the ballpark. My boat goes in the yard on Monday!...new props...shafts...and rudders.
 
Baker said:
Yessir!!! Over propping is also their enemy...and the enemy of any high strung recreational marine diesel. Under prop them a little and they will last forever.

The boat/engines I bought have only 350 hours on them. "Marine age" is always a concern but not much damage can be done from over propping in that period of time. Also, the engine survey showed no symptoms of damage due to these concerns. I will be getting new props and be basically shooting in the dark on the pitch. It left the factory with 23x28 and Timjet said his boat was over propped at 23x27. So I am gonna go with 24 pitch. He is gonna go with 22. His boat is VERY similar to mine(Carver 355) with the same engines. I think we will be in the ballpark. My boat goes in the yard on Monday!...new props...shafts...and rudders.
Click to expand...

Under propping is a great idea.

When I repowered our boat we went from a 24x24 to a 24x22.

This spring I tried a wot test after a year and a half of time on them and the bottom paint. Was able to reach 2960 rpm with egt of slightly under 900
 
Perfect...assuming it is a 2800rpm motor. How heavy is your boat???
 
Baker said:
Perfect...assuming it is a 2800rpm motor. How heavy is your boat???
Click to expand...

The factory says 30k empty I think

I tested it full fuel full water, skiff, all my junk

Probably 37k or so but that's a guess

The engines are 330 cummins
 
ksanders said:
The engines are 330 cummins
Click to expand...
I had the Cummins dealer over to my boat today to service the complete raw water system and change the impeller. The tech was an ex Navy guy (7 years) who worked on diesels in the service. I ask him for his honest opinion of the 330B engines and he said "they are the best engines Cummins ever built."
He also said that the Navy is full of them...admirals barges, captains gigs, etc.
 
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SeaHorse II said:
I had the Cummins dealer over to my boat today to service the complete raw water system and change the impeller. The tech was an ex Navy guy (7 years) who worked on diesels in the service. I ask him for his honest opinion of the 330B engines and he said "they are the best engines Cummins ever built."
He also said that the navy is full of them...admirals barges, captains gigs, etc.
Click to expand...


Cool!

Thanks!
 
SeaHorse II said:
I had the Cummins dealer over to my boat today to service the complete raw water system and change the impeller. The tech was an ex Navy guy (7 years) who worked on diesels in the service. I ask him for his honest opinion of the 330B engines and he said "they are the best engines Cummins ever built."
He also said that the Navy is full of them...admirals barges, captains gigs, etc.
Click to expand...

Any word on the after cooler???
 
Changed out the impellers on my Cummins BT5.9M yesterday. Anybody think I waited a little too long. The 2nd picture is the debris, pump vanes I took out of the port tranny cooler inlet.:eek:
 

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Baker said:
Any word on the after cooler???
Click to expand...
I forgot to mention that the after cooler was fine. :thumb:

The impeller interested me as the old one was very stiff when flexing the vanes while the new one's vanes flexed easily. Because of this difference in flexibility, it would follow that the new impeller will not see the forces the old one did and may not pump as efficiently. Has anyone else noticed this difference or does an impeller "work harden" during its life?
 

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Mine seem stiffer after 2 years of service than the new ones that replace them which are pliable.
 
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