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-   -   Cummins 6BT5.9M Injectors (http://www.trawlerforum.com/forums/s6/cummins-6bt5-9m-injectors-28888.html)

Ex Sailor 11-03-2016 07:07 AM

Cummins 6BT5.9M Injectors
 
Further to my previous question re: injectors new / rebuild, I have decided to have ALL my injectors rebuilt after we launch in 2017.

If I pull the old injectors out " myself ", is there anything to know or watch out for during or after removal ? what is the process if any ? I plan on taking them offsite for the rebuild and have the marina mechanic re install.

Thank you .. FB

Jetstream 11-03-2016 07:43 AM

FB there is a very good article on the boat diesel forum detailing just this operation. It lists all the required tools and how to do it. Might be worth a look but you do have to be at least a level one member,

Brett

BerettaRacer 11-03-2016 07:46 AM

They pop out pretty easy, just be careful with the small banjo fittings on the return lines. I made up a tool with an old nut that screws on to the fuel supply fitting and a slide hammer to pop them out. Conical wire brush in a drill to clean the paint and carbon from the hole. Crank the engine a few revs to blow out the cyl. Thin coat of hi temp anti sieze and all new copper seals on install, again being REAL careful on the return banjo's, seating the new horseshoe copper seals. I leave the fuel lines loose and crank a bit to prime, gets a little messy, have a few diapers handy. Just as she's about to fire tighten every thing up, Spray 9 and rinse to clean up any residual fuel so nothing around what will be a hot manifold, then let her rip, tater chip, lol.

Baker 11-03-2016 10:00 AM

Is there a reason why you are replacing/rebuilding your injectors?

C lectric 11-03-2016 11:12 AM

I won't comment on whether you do or don't need to get the injectors done. That's your choice.

However, if that is really needed then I would have a DARN HARD look at the filter setup you run. If the filters are good there should be no need to rebuild injectors in normal pleasure service for thousands of hours. If some dirt or water got past the filters then the filters are not good enough. COnsider that if the injectors have been harmed by dirt or water, that those contaminants got through the injection pump so some damage has been done there.

While looking at Boatdiesel site take a further tour and go to Seaboard Marine site and do some reading about fuel filtering. YOu do not have to use the filters as listed but learn and use the information

www.Boatdiesel.com

Cummins Marine Diesel Repower Specialists

Ex Sailor 11-03-2016 11:38 AM

It was a logical step as per marina mechanic. One of the cylinders on each engine are running visibly colder ( to the touch ) there are signs of unburned fuel in one engine as well. Re: filtering ...not an issue, had the fuel polished last year and have double filtering. All bowls are clear at end of season so that was that .... Also ... one cylinder is prone to air lock, the mechanic thinks that maybe that injector is not holding back the back pressure ?? ( as there are no air leaks in the fuel system thus far ). In short, the injector rebuild seems a logical starting point.

C lectric 11-03-2016 12:41 PM

Fair enough. Too often they are the first thing done if an engine is not operating well and the owners get a big bill and the engine doesn't run any better, maybe worse.
Sounds like you may have some specific problem[s].

Do not throw away the old injectors if any are replaced.

I hope you will take the time to look up and read the articles about filtering though evne if at this time you don't need it.

BerettaRacer 11-03-2016 02:18 PM

Typically the standard 6bt injectors have about a 1200 service life, they may run after that but performance may be degraded and producing a little sheen etc.

This is a copy of part of a post I did about a year ago talking about the boat I run with the 6bt's, my engines have 14,000 hrs each:

Cummins factory reps did this install back in mid 90's, we were a test bed for the factory at the time, (don't ask, long story). Initially they were hoping for 1500 hrs, but by 1200 you could begin to see a sheen from the exhaust, and that became the standard.

Remember, the 6bt is basically Chrysler a truck engine.
1800 RPM = 60 MPH
60 MPH x 1200 hrs = 72,000 mi if in your truck

My engines @ 14,000 hrs x 60 MPH = 840,000 mi

sunchaser 11-03-2016 02:24 PM

BR

Are you saying 1200 hours on a set of marine 6BT injectors is the practical limit?

BerettaRacer 11-03-2016 05:52 PM

Thats been about it for us. It's not a sudden dropoff or catastrophic failure, but you can start to see obvious signs of degregation. Little more smoke/haze, dirtier hull, sheen on the water etc. After 12-1500 I'll change them out on the next downtime cycle.

In the last maybe 8000 hrs total run time I've only had one catastrophic set of injectors failure, and it wasn't their fault. Going thru regular routine I transferred fuel from a storage tank into the day tank, unfortunately there had been a leak in the storage tank top and probably let 20-30 gals of water in, it went straight to the bottom of the day tank and within minutes I had pure water running thru the Racors, booooommm. Lights out.

A lot, a lot of work to fix, a lot!!! We were at a small resort island in the Bahama's so had to do it all ourselves. Couldn't move the boat or even start any other engines because day tank fuel was contaminated. All new injectors, new fuel pumps, new primary and secondary filters, Racors rebuilt, two guest cabins torn up to access the fuel tanks, inside the tank cleaning, and multiple passes of polishing over 5000 Gal fuel over and over again. Then had to find and fix the leak that caused the problem in the first place. Put it all back together, get carpets re-stretched, and had ozone machines flown in and ran for months to get rid of diesel smell. All this on top of our normal busy workload. Ahhh, yachting, isn't it funnn!!

Cruising=Repairing your boat in exotic locations.
Or, in our case, getting paid to repair the boss's boat in exotic locations, while other people are having fun, and telling you how nice it is and what a good time they're having, lol.

Baker 11-03-2016 09:28 PM

Quote:

Originally Posted by BerettaRacer (Post 493611)

Cruising=Repairing your boat in exotic locations.
Or, in our case, getting paid to repair the boss's boat in exotic locations, while other people are having fun, and telling you how nice it is and what a good time they're having, lol.

I think it is...."Cruising...fixing your boat in exotic locations. Yachting...having someone else fix your boat in exotic locations". It sounds like your boss is "yachting"!!!

sunchaser 11-04-2016 06:26 AM

Quote:

Originally Posted by C lectric (Post 493554)
I won't comment on whether you do or don't need to get the injectors done. That's your choice.

However, if that is really needed then I would have a DARN HARD look at the filter setup you run. If the filters are good there should be no need to rebuild injectors in normal pleasure service for thousands of hours. If some dirt or water got past the filters then the filters are not good enough. COnsider that if the injectors have been harmed by dirt or water, that those contaminants got through the injection pump so some damage has been done there.

While looking at Boatdiesel site take a further tour and go to Seaboard Marine site and do some reading about fuel filtering. YOu do not have to use the filters as listed but learn and use the information

www.Boatdiesel.com

Cummins Marine Diesel Repower Specialists

Worth repeating.

bayview 11-04-2016 10:13 AM

Injectors can be tested at any diesel pump shop. IMO better to know there was a problem than just throw parts at it.

BerettaRacer 11-04-2016 10:51 AM

Quote:

Originally Posted by bayview (Post 493760)
Injectors can be tested at any diesel pump shop. IMO better to know there was a problem than just throw parts at it.

If your going to go thru the trouble of pulling them out for testing, it's not much more $$ to turn them in as cores and pick up a set of re-mans and do a clean install. You need all new seals anyway, plus the clean up and re-painting the head.
Or, pick up a set of re-mans to install, then get originals tested/serviced and set aside for spares.

jleonard 11-04-2016 01:18 PM

Those injectors also come out very easily with a small pry bar. I have done several sets that way on trucks.

bayview 11-04-2016 01:40 PM

Quote:

Originally Posted by BerettaRacer (Post 493769)
If your going to go thru the trouble of pulling them out for testing, it's not much more $$ to turn them in as cores and pick up a set of re-mans and do a clean install. You need all new seals anyway, plus the clean up and re-painting the head.
Or, pick up a set of re-mans to install, then get originals tested/serviced and set aside for spares.

Simple reason is that I like to understand why something was fixed so that I may be alert for future issues.

Gurryman 11-04-2016 08:36 PM

If you keep your eyes open you can find OE Cummins New not rebuilt injectors for your motor for $50 each. I keep a spare set on the shelf.

Sent you a PM, Ex Sailor

sunchaser 11-04-2016 09:36 PM

Quote:

Originally Posted by Gurryman (Post 493883)
If you keep your eyes open you can find New not rebuilt injectors for your motor for $50 each. I keep a spare set on the shelf.

OEM or Chinese?

Gurryman 11-04-2016 09:51 PM

Genuine OE Cummins

sunchaser 11-05-2016 07:15 AM

Quote:

Originally Posted by Gurryman (Post 493899)
Genuine OE Cummins

Almost the same price as spark plugs then, amazing! Of course the newer piezoelectric - a different price, filtering needs and replacement strategy story.


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