Cummins 5.9 BTA Injector longevity

I recently purchased a 2000 NT37 with a Cummins 5.9BTA 330hp motor. The motor and Northern lights Genset have about 4300 hours. The manual lists maintenance schedules out to 2 years, never once mentioning injectors. The manual has instructions for replacing them but no recommendation as to when. With this being a single screw, I am trying to get motor up to date on all maintenance. Should injectors be on my to-do list, or not something to be concerned about.

The motor smokes a bit when cold, but runs good. It is still very efficient, pushing the boat at 8knt and burning about 2gpm. I don't think I have any indication of injector issues.

Thoughts? Other parts I should be concerned about? Water pump?

Things in process:

5.9BTA: Coolant flush, new thermostat, new belt, new air intake, new transmission oil, engine oil and filters, fuel filters, impeller, wet exhaust inspection (read the articles), heat exchanger maintenance, aftercooler maintenance.

Genset: Coolant flush, thermostat, belt, air filter, oil filter, fuel filters, new brushes, impeller.

Injectors? Something I should add to the list?

I've never replaced an injector other than for failure. That said, I might enquire on the price for a set. My Dodge pickup with the 6BT 220 HP Cummins has 9,600 hours on the original injectors.

Things you might add to your list:

Radiator caps. They're inexpensive, need to work as designed, and the gasket gets tired over time.

If you don't replace them, i would have spares of the idler pulley and belt tensioner. They will fail eventually.

I have spares for both engine and generator, of the freshwater pump and the saltwater pump in addition to impellers and a rebuild kit (depending on price versus replacement) for the saltwater pump. Keep enough coolant on board to do a replacement when the freshwater pump fails.

Depending on your cruising, I would keep a spare fuel lift pump for each.

Do you know if the starter or the alternator has been replaced / rebuilt?

Check the manual on your generator end bearing replacement hours. Had my generator out of the sound shield to repaint the pan on the sound shield and figured replacing that bearing was cheap insurance.

Ted

No one answered so I will take a shot. I am not a mechanic.

I would put it on your list but maybe last. You are not getting excessive white smoke when running normally. When I had my injectors serviced at 1000 hours 1 injector needed to be rebuilt.

I went through the same process with my 6BT5.9. The most important item is going through the seawater side of the engine. Also adding the capability to fresh water flush and using it after every use will keep your engine's seawater side clean.

I did replace my water pump but it was dripping. The rebuiid kit was pretty expensive so I just replaced with new.

Some other things I did was adjust the valve clearances. If I remember correctly this was a 500hour manual recommendation. I also replaced all the hoses and touched up all the rust spot on the engine and mounts. I added a Wolverine Oil pan heater to help with the cold starts and de-moisturize the engine.

sbmar.com is a great resource. I would read every article on the site. Also, the $25 bucks a year for boatdiesel.com is a great investment.

Hope this helps.
Will

"The motor smokes a bit when cold, but runs good. It is still very efficient, pushing the boat at 8knt and burning about 2gpm."


White smoke on a cold motor is normal.


2 GPH (I doubt you can burn 2gpm) translates to 35-40HP a very minor amount from a 330hp engine.. I would suggest an oil sample , and perhaps more frequent oil changes.

I too do not mess with injectors unless there is some sort of symptom.

The most reliable injector is one that has worked well for many hours and many years.

New ones or rebuilt ones often have reliability issues (infant mortality) and have to monitored closely until they get some time on them.

The B330 will smoke at cold idle, nature of the beast. New injectors won't help that. If it smokes at warm idle, then time to look hard at it.

Think about changing all the hoses involved in the cooling system. Cheap insurance. While you do that replace the radiator caps.

If there is no record of them having been serviced and you are looking for a project, it is probably about time to get them serviced. It will cost you about $75.00 per injector for a rebuild. The in and out will take a few hours and it's kind of a pain.

At close to 5,000 hours you WILL notice a difference when they go back in.

pete

Dont idle it just start and go. Idling wont really get the cylinder temp up

Thank you for the thoughts. That is helpful and the experience pool here is deep. 2GPH, not minutes, sorry. That would be a problem. I can certainly burn more fuel and push the boat faster, but have found that to be about the sweet spot of speed and efficiency.

I got new radiator caps for main and gen, forgot to mention that. They are cheap and should be replaced occasionally.

I've been reading a lot on sbmar.com. That is very helpful. I'm headed there this morning to inspect the wet exhaust. I also ordered flush caps for both sea strainers. After servicing the heat exchanger and aftercooler, I will careful to fresh water flush and try to keep them clean.

I also have valve adjustment on the to-do list but haven't done it yet.

Good thoughts about extra pumps and things to add. Thanks!

I had a 2005 QSC 8.3 Cummins with about 1800 hours and the signs of my bad injectors were intermittent surging--RPM up and down and a occasional mild rough running.
Starting and smoking were not an issue.
Diagnostics pointed to injectors--removed them and sent them for testing and was told 5 of the 6 failed. Replaced them and problem solved. I don't know why they went bad so soon--I bought the boat with about 1500 hours on it so no high quality long term history of use

I would suggest a couple of upgrades from Seaboard:

https://www.sbmar.com/product/idler-pulley-upgrade-kit/

https://www.sbmar.com/product/smx-1730-seawater-pump/

ktdtx said:

I had a 2005 QSC 8.3 Cummins with about 1800 hours and the signs of my bad injectors were intermittent surging--RPM up and down and a occasional mild rough running.
Starting and smoking were not an issue.
Diagnostics pointed to injectors--removed them and sent them for testing and was told 5 of the 6 failed. Replaced them and problem solved. I don't know why they went bad so soon--I bought the boat with about 1500 hours on it so no high quality long term history of use

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I think injectors on a common rail electronic engine are a different animal than the mechanical ones we are talking about.

Lat 58,
Richard gave you a couple of great ideas from sbmar. Earlier info is good as well. Tony Athens offers great free advice, and lots of it. Definitely replace the exhaust elbow if it is original and/or Cummins stock. It will eventually feed saltwater to your turbo and beyond. There is a great article on sentoa.org under maintenance tips regarding the exhaust elbow issue on early NT 37's. Get a custom elbow from either Tony, or National Marine Exhaust in Marysville, Wa. Scott at National built Kelly's and mine and we are both satisfied customers.

Kelly, the guy who wrote that article has over 10,000 hours on his 2001 NT 37 and still going strong.
I use Tony's Envirovent CCV system and like it (to me it is simple and makes sense), and I have removed the fuel cooler, which removes a potential failure point and gives much easier access to the raw water pump for servicing. The cooler is not really needed. Ask Tony if needed. I did not use Tony's kit, I just had a fuel hose fabricated locally, kept the combo block, and put in a new raw water hose.
Also check out your WOT rpm. Can you reach, or better yet slightly exceed rated spec? If not you might be overpropped? Tony talks about this in his articles. I also suggest installing a Wolverine oil pan heater. It will keep your engine warm for good cold starts (when plugged in to shore power), and will also help keep your ER warm and dry, improving conditions for your mechanicals in the winter. Another good addition is to install a switch to be able to control the engine preheat. As it comes, the preheat will cycle on and off (potentially really loading up the alternator) until the engine reaches either a set RPM or temperature. Having a switch, allows for manual control. I also suggest having either or both of the following installed: raw water flow alarm (Aqualarm), and/or an exhaust hose temperature alarm (either Borel or Aqualarm). These can save you from a potentially costly overheat, and even burning up your impeller should you start without the through hull open.
For operations, being as we tug owners tend to run our engines at about half throttle, I suggest no idling for a warm up (just start up and leave the slip asap at under 1000 rpm) and warm up under light load until your engine reaches about 150 degrees, and every once in a while running your engine up to at least 2200 rpm for 10 minutes (or even WOT for 5 minutes) to "burn out " the carbon so to speak.
Enjoy your tug, I enjoy mine,

"Good thoughts about extra pumps and things to add. Thanks!"

Spares are great , and best if treated as the offshore sailors do.

Purchase the unit , install it and operate for an oil change ,(100? hours) then remove it and reinstall the one that was originally fitted.

This procedure insures you have the experience , and tools to R&R as well as the spare actually fits and works.

I get a chuckle out of comments like "I have 10,000 hours on my injectors, they are still going strong" or "I never change my impellers, never had a problem" Or "I don't change my secondary filters, the primary filters catch everything.

Heck, (true story) my father NEVER changed the oil in his cars. He would buy them new, run them until he got bored with them, usually a couple to three years and then trade them off. Original oil and all.

You could open the hood on dad's car and everything looked great, good as new! Probably the exact same scenario with all the other examples I cited. Things may look good on the outside but what is happening inside the engine???

pete

Injectors on most lower fuel pressure diesels built in the 1975 - early 2000s period are going to show wear for three reasons:
-- original fuel quality especially cetane, water and particulates
-- adherence to proper filtration
-- fuel consumption

Hours are of lesser importance with fuel burn rate varying by as much as 3 to 4 fold depending upon the engine RPM and load range. Once into current era high fuel pressure electronic engines injector life can be influenced by additional metrics to satisfy environmental requirements.

Failing to change injectors is not the same as failing to change oil, impellers or filters.

I just had a injector failure on my 2003 Dodge with 130,000 miles on it, my daily driver.

I’d keep a spare set of injectors onboard. The cost from Tony Athens is about $1K and if you need them, they are there.

ksanders said:

I’d keep a spare set of injectors onboard. The cost from Tony Athens is about $1K and if you need them, they are there.

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You can buy them much cheaper from a diesel performance shop. Those injectors (330s and 370s) are a common upgrade for the dodge truck folks.

Small point but not mentioned is replacing the various pencil zincs on the engine and generator. Also, Lat58 what color smoke on start up? White! Bluish? Gray/black?

Pete Meisinger said:

I get a chuckle out of comments like "I have 10,000 hours on my injectors, they are still going strong" or "I never change my impellers, never had a problem" Or "I don't change my secondary filters, the primary filters catch everything.

Heck, (true story) my father NEVER changed the oil in his cars. He would buy them new, run them until he got bored with them, usually a couple to three years and then trade them off. Original oil and all.

You could open the hood on dad's car and everything looked great, good as new! Probably the exact same scenario with all the other examples I cited. Things may look good on the outside but what is happening inside the engine???

pete

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First off, what Ski said!!!

Secondly, Do you replace the control arms on your car on a regular basis??? What about the exhaust system??? The point being injectors generally don’t fail. Just like control arms and exhaust systems on cars don’t fail. They can fail and they do fail. But they aren’t things that require periodic maintenance. You start investigating or changing injectors when their are symptoms. No need to do it otherwise. Tony Athens even says “It is very rare that injectors are the problem.”....for whatever.

Yes, replacing all zincs too. There is certainly a lot to do when getting a new boat especially when not knowing full history or having the previous owner to explain things.

The smoke it a greyish blue I would say.

I will warm up under light load, that makes sense.

I pulled the exhaust elbow off the turbo to inspect the turbo, elbow, and exhaust hose. The turbo did not appear to have any water damage. The turbo is pretty heavily caked with carbon build up. The elbow has a lot of carbon build up but appears to be in pretty good shape. The exhaust hose is shot. It was de-laminating on the inside and had almost completely blown through one spot. I understand the design problem and need to contact National Marine Exhaust. They have been recommended by multiple people so far. But, I can't do it all at once. I'll clean the elbow and turbo and reinstall them with a new exhaust hose. That one lasted 20 years, surely I have a little time to use the boat, monitor and assess.

I am concerned about the carbon build up and wonder if it is a bit excessive. It appears the engine is burning some oil.

I don't have enough history with the boat yet to establish a baseline or have a good understanding how it is working, if it is burning oil or how much it is burning.

I'll put it back together and use it. I'll mark temperatures on the engine and use an IR gun to look for and mark hotspots on the exhaust hose too. That information and the old hose will be useful for National Marine Exhaust when the time comes.

Based on some recommendations, I am replacing the coolant pump, idler pulley and raw water pump as well.

Is the Killer Dowel Pin a thing? A friend said it has been an issue and a necessary fix for cummins 5.9s in this year range (mine is a 2000). I searched the forums and found very little. There is a lot in the truck realm, but very little on boat forums. Almost nothing on sbmar as well, other than one person asking about it.

Lat, I wouldn't worry to much about using oil....unless it is a significant amount. Also, if you are unaware of the problems with the shallow oil pan on the 6BTA, but there are issues that could be causing your percieved oil burn. If you are fillinf your engine all the way to the top of the stick, it might be whipping the oil and burning it or blowing it out. Try letting it "disappear" and see if it finds a happy spot on the stick before going below the "low" line. If it does, leave it. I have an old air cooled Porsche that does this. If you fill it all the way with oil, it will burn it until it gets to the lower part of the stick and then it stabilizes. It is well known with those cars and this is well known with these engines.

Either way, a small amount of oil burn is not something to be terribly concerned about.

If boat has been run at low power, that carbon can really build up. Does not mean it is using oil. Best to get it out on the water and run the engines up to higher power setting.
No need to go full power, but up to like 2400 for a B330 which is rated at 2800. That will burn most of the carbon out. 15min should do it.

Lat58 said:

Is the Killer Dowel Pin a thing? A friend said it has been an issue and a necessary fix for cummins 5.9s in this year range (mine is a 2000). I searched the forums and found very little. There is a lot in the truck realm, but very little on boat forums. Almost nothing on sbmar as well, other than one person asking about it.

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I called SBMAR. They said KDP issues involved motors in the early 90s and VERY rarely in marine world. If anyone would know, I would guess they would.

Lat58 said:

I called SBMAR. They said KDP issues involved motors in the early 90s and VERY rarely in marine world. If anyone would know, I would guess they would.

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I have never heard of it....and have been a Cummins Owner for a while. Those 330Bs are really good engines. I ran mine at 2300-2400 all the time. I was slightly underpropped as well. I would expect many more thousands of hours even at that higher power setting. They weren't even breaking a sweat. My current boat has 450Cs and is somewhat "overpowered"....most of my models were made with the 370Bs. I can cruise at an "easy" 20 knots but push it up to around 25kts at MCP of 2400. But, I never run it up there....as I never ran my Bs at 2600RPM...MCP. But they could sure as hell handle it as long as your cooling system is healthy and you are not overpropped.

Thanks for the info about the oil burning. I will monitor it, and resist the temptation to constantly top it off.

8knt and burning 2 GPH is excellent!!! We have a QSB5.9 - 305hp and burn 5-6 GPH @ 8kts (1800 rpms)...

Cummins alternator is only good for 2000 hrs. Check alternator temp/volt/amps frequently - should be 175 degrees/26-28v/80-200amps?. Have a rebuld kit on bvoard and a full spare alternator to swap out.

Genset: exhaust elbow check frequiently, replace every 5 years and have a spare Stainless Steel one on board.

~Lucky Chucky