Aftercooler maintenance

[rslifkin]

It's odd
Every time one of these threads and the Tony Athens pics come up I go into mild panic mode, pull out the workshop and operations and maintenance manual for ours which covers quite a lot plus the daily, monthly, yearly checks and servicing to be performed.

No where in there is aftercooler mentioned
And an exhaustive interwebs search finds nothing regarding aftercooler servicing for the NTA 855 M
It is coolant cooled and there are no dissimilar metals used so is that it?

Having the aftercooler in the coolant loop likely leads to much lower maintenance requirements for yours. Like a heat exchanger, it's still good to give it some occasional TLC to make sure it's all in good shape, but there's a lot less risk and sensitivity to maintenance in your design.

 

[firehoser75]

It's odd
Every time one of these threads and the Tony Athens pics come up I go into mild panic mode, pull out the workshop and operations and maintenance manual for ours which covers quite a lot plus the daily, monthly, yearly checks and servicing to be performed.

No where in there is aftercooler mentioned
And an exhaustive interwebs search finds nothing regarding aftercooler servicing for the NTA 855 M
It is coolant cooled and there are no dissimilar metals used so is that it?

Simi,
It sounds like the MAJOR difference between your set up (aftercooler cooled with coolant instead of seawater) is the avoidance of exposure to salt water! Therefore, alot of what has been said in this thread does not apply (at least not completely) to your engine. However, I would be very surprised if even your aftercooler setup is "maintenance free". I would strongly suggest that it still requires SOME maintenance. For example, flushing out the coolant passages (and changing the coolant), cleaning the "air side" of the exchanger (an oily gunk can coat this side over time depending on how your engine runs), and replacing any "seals or O rings" to keep coolant where it belongs, pressure testing, etc.??? My guess would be on an interval of 4-6 years depending on use (hours per year)?
Caveat, I am not familiar with your engine, so I suggest further investigation as to what is necessary as being a good idea.

 

[Simi 60]

Simi,
It sounds like the MAJOR difference between your set up (aftercooler cooled with coolant instead of seawater) is the avoidance of exposure to salt water! Therefore, alot of what has been said in this thread does not apply (at least not completely) to your engine. However, I would be very surprised if even your aftercooler setup is "maintenance free". I would strongly suggest that it still requires SOME maintenance. For example, flushing out the coolant passages (and changing the coolant), cleaning the "air side" of the exchanger (an oily gunk can coat this side over time depending on how your engine runs), and replacing any "seals or O rings" to keep coolant where it belongs, pressure testing, etc.??? My guess would be on an interval of 4-6 years depending on use (hours per year)?
Caveat, I am not familiar with your engine, so I suggest further investigation as to what is necessary as being a good idea.

Had a look inside the air side about 12mths ago and it looked pretty clean in there to me.

I do a salt water pool filter cleaner (phosphoric acid) flush every 3 years and pull an end cap on the heat exchanger and rod it out every couple of years.

I have coolant testing strips and that's on the agenda to do new coolant when next on the hard, or probably in water after lift.

O rings I have not looked at, considering the appearance of relative ease of access, while I have the coolant out it may be worth doing O rings then - will look into that.


Thanks

 

[Pete Meisinger]

I know this is "apples to oranges" but..My old Ford Lehman is N.A., nothing fancy, nothing near 450 hp. Nothing on the engine costs over a few hundred dollars. I think my new cam was about $500, new starter $350, gasket set a few hundred, etc.

Keep it simple..

pete

 

[jim.johnson3570]

I would highly recommend installing a fresh water flush system after getting all the coolers back in shape, will certainly extend the life expectancy and also provide FW in the system when shut-down.

 

[Comodave]

I would highly recommend installing a fresh water flush system after getting all the coolers back in shape, will certainly extend the life expectancy and also provide FW in the system when shut-down.

We boat in freshwater so no salt to flush away. The Great Lakes, unsalted and shark free, as the saying goes.

 

[Delta Riverat]

Us too. We plan to venture out to the ocean eventually, Monterey is on the list.

After that who knows? San Diego, Mexico, Alaska? All possibilities after experience is gained.

But wherever we go we'll always get that fresh water Delta flush for free on the way home -

 

[ronobrien]

A buddy of mine just got stranded in S.C. due to a plugged intercooler. I have no idea what that cost him. I'm sort of glad to have FL 120's. No turbo, no intercooler. Slow but cheap and reliable. good luck.

 

[sunchaser]

Ron
As oft mentioned in this thread maintenance 101 on after coolers is easy but necessary. Since virtually all modern diesels over 100 or so HP had aftercoolers best to practice PM 101

 

[Comodave]

Ron
As oft mentioned in this thread maintenance 101 on after coolers is easy but necessary. Since virtually all modern diesels over 100 or so HP had aftercoolers best to practice PM 101

That is what started me on this path.

 

[ronobrien]

Ron
As oft mentioned in this thread maintenance 101 on after coolers is easy but necessary. Since virtually all modern diesels over 100 or so HP had aftercoolers best to practice PM 101

I absolutely agree. That should be everyone's' policy with all maintenance in general. It's always less expensive. I'm still glad I don't even have to do that much.

 

[Comodave]

I absolutely agree. That should be everyone's' policy with all maintenance in general. It's always less expensive. I'm still glad I don't even have to do that much.

To each his own. You may not have to maintain aftercoolers but then again your boat won’t get on plane. Different strokes…

 

[Turtle Blues]

Dave,
Thanks to your posting I saved my turbo.
Have twin Perkins on a boat purchased 2 seasons ago. Saw slight seepage and corrosion on the seam of the aluminum housing at the rear plate and purchased new shell to replace. Decided I better get on it and opened it up. Corrosion debris collecting at the bottom of the tube bundle had started galvanic corrosion between the tube face plate and the aluminum. When installed properly the isolation is provided by the sealing O ring. Perkins didn't believe in Zincs.

Long story short I was probably 1 startup away from blowing cooling water into the dry side of the cooler and subsequently the turbo.
Thanks Again

 

[Comodave]

That is what I was afraid of and why I was trying to service mine. Glad you benefited from my PITA…. That’s what TF is all about.

 

[ronobrien]

I've been a sailor up until now. Doing 10 knots is faster than I am used to. I will also burn less fuel than being able to plane. Yes, to each his own.

 

[Hippocampus]

I've been a sailor up until now. Doing 10 knots is faster than I am used to. I will also burn less fuel than being able to plane. Yes, to each his own.

Like you been a sailor all my life until getting a Nordic Tug 42 with a Cummins QSC 540hp. This is more than five times the HP of any prior engine I’ve had including boats of greater LOA and displacement than the current NT. Like your boat it’s a semi displacement hull. It took a couple of head slaps from friends more experienced than me with power to change my thinking.
First common rail engines are more efficient in their use of fuel than naturally aspirated engines so generate less carbon and soot but still enjoy being fully loaded or nearly so periodically. With N/A engines carbon buildup is sufficiently rapid which fouls the turbo and other components that there’s generally accepted advice as to how frequently and how long you should periodically fully load them. I’ve been told it’s not as critical for common rail engines but still worthwhile. Beyond burning off any carbon deposits fully exercising the engine is good for it and an easy check there’s no hidden problems. At wide open throttle it should be able to achieve its rated RPM. If it doesn’t there’s something up.
I want to know my oil pressure, coolant and engine temperatures are within normal range at wot. I want to know there’s no vibration nor new noise. Plus it’s fun to go on plane once in awhile. Finally it’s a safety factor. Sooner or later whoever is at the helm will screwup or some idiot will come along. Being able to get out of Dodge may save your butt. Knowing you can lowers your BP.
Lastly have already had several occasions where being able to lean on the throttle has been very helpful in improving the ride. Particularly when running with the seas or fighting wind+/or current.
The GB is a fine boat. Not using it within its performance envelope saves minimal money when viewed as a fraction of total cost of ownership. Live a little and enjoy. Your engine will appreciate it and your bottom and running gear will stay cleaner.
Still makes me crazy watching the gph as we speed up and thinking about mpg. So mostly travel below hull speed. But make it a point to get to at least 80% load on the turbo periodically.

 

[ronobrien]

Like you been a sailor all my life until getting a Nordic Tug 42 with a Cummins QSC 540hp. This is more than five times the HP of any prior engine I’ve had including boats of greater LOA and displacement than the current NT. Like your boat it’s a semi displacement hull. It took a couple of head slaps from friends more experienced than me with power to change my thinking.
First common rail engines are more efficient in their use of fuel than naturally aspirated engines so generate less carbon and soot but still enjoy being fully loaded or nearly so periodically. With N/A engines carbon buildup is sufficiently rapid which fouls the turbo and other components that there’s generally accepted advice as to how frequently and how long you should periodically fully load them. I’ve been told it’s not as critical for common rail engines but still worthwhile. Beyond burning off any carbon deposits fully exercising the engine is good for it and an easy check there’s no hidden problems. At wide open throttle it should be able to achieve its rated RPM. If it doesn’t there’s something up.
I want to know my oil pressure, coolant and engine temperatures are within normal range at wot. I want to know there’s no vibration nor new noise. Plus it’s fun to go on plane once in awhile. Finally it’s a safety factor. Sooner or later whoever is at the helm will screwup or some idiot will come along. Being able to get out of Dodge may save your butt. Knowing you can lowers your BP.
Lastly have already had several occasions where being able to lean on the throttle has been very helpful in improving the ride. Particularly when running with the seas or fighting wind+/or current.
The GB is a fine boat. Not using it within its performance envelope saves minimal money when viewed as a fraction of total cost of ownership. Live a little and enjoy. Your engine will appreciate it and your bottom and running gear will stay cleaner.
Still makes me crazy watching the gph as we speed up and thinking about mpg. So mostly travel below hull speed. But make it a point to get to at least 80% load on the turbo periodically.

A diesel being either common rail or naturally aspirated have nothing to do with each other. Common rail is a fuel injection method (fuel) and naturally aspirated simply means it is not artificially (turbo) aspirated (air). Common rail systems do operate more efficiently due to pressures they operate at and the ability to control the injection process better. (something like 5KPI vs 25KPI). Running a diesel at full throttle is primarily for the purpose of raising cylinder pressures to keep piston rings properly seated against the cylinder walls. Removing carbon is a minor side effect as the air velocities (volume over time) through the firing chamber is not significantly different as it would be in an engine (gasoline) with a much wider operating range. That said it is quite advisable to run the engine at full load for 10 minutes or so each time out to raise those cylinder pressures for the stated reasons. Running at full throttle continuously consumes much more fuel and has the potential to reduce driveline life due to increased continued stress. I never said I wouldn't do those things, I said that I viewed not having a turbo or an intercooler/aftercooler as a reduction in maintenance concerns. I am also not running the boat at 10KT max as an option, that is pretty much the max speed we experienced on sea trial in a 6' sea. The boat has been out for refit for a couple years. I will see what she does after that. Said and done, the boat is the boat I have and I just try to view the positives I do have as opposed to the options I don't have at this time.

 

[Hippocampus]

https://www.passagemaker.com/technical/troubleshooter-wide-open-throttle

Tony A says with proper maintenance no difference in service life regardless of load as long as routine maintenance done and engine operated on prop load curve

“And I need to mention something else related to this discussion that chaps my hide way too often. It’s often said typical dock talk) that you must run a diesel at 70-80% load for max life/efficiency. I say total Horse Manure and the answer is right in this article. Just look at the QSM11 for a perfect example.

Put the 300HP version of this engine on a dyno producing 215 HP @ 1600 RPM burning 10.6 GPH just like on the attached graph below, and leave it there “forever”. The 300HP version will be running at approx 72% load. Next to it on another dyno, use the 715 HP version and set it up to produce approx 215HP at the same RPM burning 10.6 GPH. The 715 HP version will be at about 30% load. Both engines would be on the “factory prop curve” at the same RPM ( how could that be?) . Outside of the maintenance that each engine would require when “running forever” , (and, I will take this to the bank) ———– Both engines will last the same as to “wear & tear” and both would have no measureable efficiency differences between them that matters. And, how long might that be? I’d say not less than 30,000 hours or 300,000 gallons of fuel burned at that load & RPM with all of the right maintenance done applicable to that engine.”

As said running at full load periodically does no injury and allows you to pick up nascent problems. Also it’s fun and looking at COO not as big a deal as I initially thought. Personally save the money by staying out of marinas whenever we can.

 

[DDW]

Running for a period at WOT or heavy load may do more than just increase the ring pressure. It will raise the EGT significantly (like from 500 deg to 900 deg) which will turn some of the carbon in the exhaust and turbo hot side to ash. Almost all modern truck diesels heat the exhaust periodically to do this (though it is done by dumping extra fuel in, rather than operating at high loads).

All that said, I continue to marvel at the durability of the mythology "you've got to run a diesel hard". Most of the world's diesels aren't run that way without issues, why would boats be different? Injector and slobbering problems are history with common rail injection.

 

[ronobrien]

The "after treatment system" on trucks is called a "one box" in the industry. It is a 3 bed catalyst system that reduces NOX, or Oxides of Nitrogen, as it's primary function. It consists of 1) Oxidizing chamber followed by 2) DPF or diesel particulate filter and then 3) the NOX reduction bed, which is where the true catalytic action takes place using the DEF fluid (uric acid). The heating of the exhaust by direct fuel injection ahead of the DOC chamber is to help clear the soot which accumulates in the DOC and DPF chambers. It has no effect on clearing anything from the engine itself. The heating and fuel injection is not an emissions function directly but a maintenance process for the "One Box." My knowledge may be outdated but it was solid information from my days associated with the Mack Truck Engineering Dept. It's true that a boat will operate at more of a consistent load than a truck will, but running it at lower load doesn't do it any good.

 

[Hippocampus]

Have to put piss in my car. Just glad I don’t into my boat.

 

[Comodave]

The "after treatment system" on trucks is called a "one box" in the industry. It is a 3 bed catalyst system that reduces NOX, or Oxides of Nitrogen, as it's primary function. It consists of 1) Oxidizing chamber followed by 2) DPF or diesel particulate filter and then 3) the NOX reduction bed, which is where the true catalytic action takes place using the DEF fluid (uric acid). The heating of the exhaust by direct fuel injection ahead of the DOC chamber is to help clear the soot which accumulates in the DOC and DPF chambers. It has no effect on clearing anything from the engine itself. The heating and fuel injection is not an emissions function directly but a maintenance process for the "One Box." My knowledge may be outdated but it was solid information from my days associated with the Mack Truck Engineering Dept. It's true that a boat will operate at more of a consistent load than a truck will, but running it at lower load doesn't do it any good.

Ok, what does this have to do with aftercooler maintenance?

 

[DDW]

The "after treatment system" on trucks is called a "one box" in the industry.

......

It's true that a boat will operate at more of a consistent load than a truck will, but running it at lower load doesn't do it any good.

Running at lower load will not do it any harm either.

In trucks, the exhaust is heated by over fueling to burn the diesel soot in the DPF. But it also burns up the diesel soot elsewhere in the exhaust. The soot deposits everywhere, the DPF just keeps it from exiting the exhaust. If you run a diesel with a DPF at high enough load (and exhaust temp) you rarely or never need a regen cycle.

 

[sunchaser]

All that said, I continue to marvel at the durability of the mythology "you've got to run a diesel hard". Most of the world's diesels aren't run that way without issues, why would boats be different? Injector and slobbering problems are history with common rail injection.

Correct. Many of our diesels are used as gensets and locked for life at 1800 Rpm. These applications can yield many thousands of hours.

 

[ronobrien]

Ok, what does this have to do with aftercooler maintenance?

Nothing. I was correcting a couple of posts that stated incorrect facts. I didn't initiate the conversation I just followed up. That sort of thing is how poor maintenance sometimes takes place. Just the facts ma'am.

 

[Hippocampus]

Running for a period at WOT or heavy load may do more than just increase the ring pressure. It will raise the EGT significantly (like from 500 deg to 900 deg) which will turn some of the carbon in the exhaust and turbo hot side to ash. Almost all modern truck diesels heat the exhaust periodically to do this (though it is done by dumping extra fuel in, rather than operating at high loads).

All that said, I continue to marvel at the durability of the mythology "you've got to run a diesel hard". Most of the world's diesels aren't run that way without issues, why would boats be different? Injector and slobbering problems are history with common rail injection.

When you say the “hot side” do you mean the hot air expelled by the turbo before it reaches the aftercooler/intercooler?. If so wouldn’t the above posts be relevant to intercooler/aftercooler maintenance?

I think I understand that with the advent of common rail computer controlled measuring of the air and fuel entering each cylinder the amount of soot/carbon generated is markly decreased to the point with proper maintenance it doesn’t effect service life. But some is still produced. What I remain unclear about is whether there is or not benefit beyond picking up latent troubles or more firmly seating things.

I’m also uncertain about gensets. I’ve had both high and low rpm gensets. No question in my mind low is better. Similarly prefer prior Northern Lights to my current Onan. Simpler and easier to maintain. But I’m uncertain about comments about constant rpm. I’ve been taught given in the hp range of these engines in rec boats they don’t have tier requirements applied so are usually simple NA engines . But unlike propulsion engines you can vary load. Just put on the AC, vacuum, make water etc. I’ve been instructed that’s it’s bad for a genset to only be run at low load. It’s better for it to be run at significant load. Is this true?

 

[rslifkin]

Most engines benefit from at least occasionally seeing periods of higher load (this doesn't have to mean WOT or high RPM though). How much you can run at really light load without issues will depend on the specific engine. Some tolerate it well, others not so much.

 

[ronobrien]

When you say the “hot side” do you mean the hot air expelled by the turbo before it reaches the aftercooler/intercooler?. If so wouldn’t the above posts be relevant to intercooler/aftercooler maintenance?

I think I understand that with the advent of common rail computer controlled measuring of the air and fuel entering each cylinder the amount of soot/carbon generated is markly decreased to the point with proper maintenance it doesn’t effect service life. But some is still produced. What I remain unclear about is whether there is or not benefit beyond picking up latent troubles or more firmly seating things.

I’m also uncertain about gensets. I’ve had both high and low rpm gensets. No question in my mind low is better. Similarly prefer prior Northern Lights to my current Onan. Simpler and easier to maintain. But I’m uncertain about comments about constant rpm. I’ve been taught given in the hp range of these engines in rec boats they don’t have tier requirements applied so are usually simple NA engines . But unlike propulsion engines you can vary load. Just put on the AC, vacuum, make water etc. I’ve been instructed that’s it’s bad for a genset to only be run at low load. It’s better for it to be run at significant load. Is this true?

In the case of gensets the constant RPM is to maintain 60HZ. It is not advisable to consistently run them with a light electrical load, presumably for benefit of the engine. I am not aware of any benefit higher loads has for the electrical end, and it would seem that higher loads stresses the winding insulation more.

 

[Hippocampus]

It is not advisable to consistently run them with a light electrical load, presumably for benefit of the engine. “

So what’s the take home? Is it or not of benefit?

Related question. Prior boat allowed me to not use a sound enclosure. Noise in the boat was minimal. Current boat has a sound enclosure. Is it better for gensets to not have a sound enclosure?

Last question. Does any of this really matter? Is the difference in practice have any meaningful effect?

 

[ronobrien]

It is not recommended that they (generators) run at light load. As I don't see where the higher load would benefit the electrical end, the recommendation would, therefore, seem to be for the benefit of the engine. I think this ties into the theme of this thread about the benefits of running diesels at high loads on occasion. As the RPM in a generator can't be varied, the load must come from increasing the electrical demand. Some manufacturers require an outside source of cooling for the electrical end. Follow their specific advice. As to the real benefits, I have seen the effects of NOT running them hard, poor ring seating, excess oil consumption, erratic firing patterns due to oil infiltration to the cylinders, burned pistons. How much, how often I can't really say. I just take "rather safe than sorry" approach.