Small Diesel Rebuild Hours

Basically, once they get up in hours like yours, I just have them scoped and compression checked. If the results look good I'd just keep running them. I've seen them go over 15,000 hours before needing a rebuild.

Now if you have the down time and the owner goes for it, you certainly could justify having them rebuild at this point as a preventative measure. I'd have the AC end gone over at the same time of course.

I was quoted by Alaska Diesel (the owners of Northern Light), that they typically will go 20,000 hours in a private yacht situation, and 40,000hrs in a commercial yacht.........Having them scoped and checked is a good idea...... but really IMO doesn't tell you much......I've seen engines with no hash marks go a long long time.......and motors with nice hash marks snap a crankshaft. Why don't you talk to the manufacturer and ask them their opinion of their engines instead of here.

ychtcptn:

I thnk yr gttng ffly cls t ndng rblds @ 14K hrs.

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Loren may have spent to much time in the "Who's Drinking Tonight? thread

Or practicing Ebonics, hehehehe

Me thinks he spends a wee bit of time txtng. and foregot which keyboard he was on.

40,000 hrs....Holy cr...

That is more than twice as much as I thought possible on a diesel engine.

I sure would like to know what RPM they run 'em and what brand of oil they use. (Synthetics?)

I'm trying to figure out why in a commercial app. you would get twice as many hours out of them. Is it just because they run almost full time while at or near their ideal loads most of that time?

my-B Lrn nd Ychtcpn dnt uwz vwls

That's what I was quoted, but meant to say Commercial boat. Yeah, temperatures remain constant so you have little wear from expansion and contractions of metals, oil temp, (cold starts add wear), load remains fairly constant and they stay loaded, they run all of the time so they don't get condensation in the oil and such from sitting. I would say it's a combination of all of the above. Sort of how highway miles are much easier on a car then city miles.

Commercial app - professional engineers, private app - amateur Captains, rather simple

What difference would there be if the Captain on a private yacht had the dealer do all of the servicing at the recommended intervals, and made sure the fluids were at the proper levels over a professional engineer? The professional engineer isn't going to do anything differently then the Northern Lights dealer would do.

And if the professional engineer adjusted the valves and this and that instead of the dealer doing it, it would void the factory warranty anyways, unless the engineer was certified by Northern Lights. However, a professional engineer should know how many hours the generator they are overseeing is rated to go between overhauls in the first place. I believe it is published in the owner's manual. CAT publishes longevity in their maintanence schedule and owner's manual and I'm pretty sure Northern Lights does also. Although it's been a while since I looked in a Northern lights owner's manual or maintained/ran one.

The frequency (how often) that the Generator is run in the commercial application and how it is run (non-stop for days at a time) has more to do with the longevity. Sitting for weeks and weeks without running, or not running with enough of a load does more damage to them then anything.

I've also seen a 16kw Northern Lights fail at 1000 hours and need a major due to running with too little of a load and a leaking exhaust riser.

A simple call to Alaska Diesel in Pompano Beach,FL, or a visit will tell you everything you need to know on how long they're expected to run. They're very nice people over there last time I stopped by.

Hi,

In order to determine if it is in dire need of an overhaul you should be able to get a reasonable idea of how it's general condition by a few different methods.

The best would be if it or they had had their Lube Oil sampled regularly throughout their life cycle.

Any increase in wear metals and or Oil Consumption between samples will be a first indication something is starting to change.

If the Oil Samples were all pretty even and no red flags were raised the next thing to look at and to all intents and purposes the engine seems to run ok a bore scope can reveal how much cross hatch is left on the liners, if the valve clearances are not always tightening up there isn't an indication one is about to fall into the cylinder. While the injectors are out a compression test is also a worthwhile operation.

If you do have smoke issues and everything else seems ok then a service of the pump and injectors and air side ( filter, charge air cooler, turbo if fitted) of the process might be all it needs.

I have often seen properly maintained and use engines go a long way past the manufacturers recommended intervals, in many cases these should be used as a guideline.

You are not going to do any harm to your engines warranty once it is out of warranty by adjusting valves etc. I am also yet to see one that is still under warranty with 14k hours on it.

Just doing a one time oil sample now will not tell you much about what has led to the current condition but will if continued give you a start point to monitor future changes.

Was that "turnip truck" next to the "banana boat".

Caterpillar give guide lines as for how much fuel is used more than emphasizing the hours, other manufacturers give running hours and or years. As in 1000 hours or 2 years.

Once up over the 10,000 hour mark it is cross your fingers time, like CaptJ says they fail at 1000 hours although there was a N/L model that had bad crank shafts and failed within 5 or 6 hours. Thankfully they found the problem and got them fixed.

Oil samples are good if taken from the start and done on a very regular basis but they are also as good as the lab you send them too and more importantly if the person reading them understands them. I had one engine surveyor who had no idea how to make use of the information and only started taking them after I told him how much he could make per sample.

I have seen some folk only rebuild the heads, injection pump & injectors and in my opinion that loads up the engine to the point that the bearings throughout can not handle the loads and not long after trying to save some money you end up doing a total rebuild any way.

When rebuilding the large engines (1000+KW) we strip them down to a bare block and then after cleaning we do a full crack test before rebuilding and we always do deflection readings.

On smaller engines you may want to look into short or long block replacement from a manufacturer or dealer ensuring there is a water tight warranty.

Besides worrying about the engine end having a very good electrician check out the electrical end should be carried out and as far as I know there is no book out there that tells you the electrical end should be re-wound after every so many hours. A mega test may tell you something there.

PS. you could take that brand new Cummins engine Onan generator off the back of the turnip truck and install that.

Sorry, to simple an answer for me.

I think the answer is more along the lines of what I thought. How the genset is used and loaded.

An amateur captain can have a tech come in and do the scheduled service the same as an professional engineer would do.

Simplistic answer, however, in a commercial application that generator or any small engine should have been maintained by a professionally trained engineer who may have had the oppurtunity to bring in a manufacturer's technician to carry out the first service but after that it is up to the vessels engineer(s) to carry out all maintenance work.

Right from initial start up proper records should have been maintained and the engineer onboard would and should know all schedules. Oil samples taken and checked etc.

Maybe I should have written "Private App - amateur Engineer" usually carried out by those who think they know but in reality cause more problems.

I have twin 65KW Northern Lights gens with the 4.5L JD motors, both gens have PTO's for hydraulics. Right now they have over 17,000hrs on them without a in-frame rebuild. At 12,000hrs the heads were pulled and re built. All of the preventative maintenance is kept up like clockwork and we do not plan to have an in frame rebuild until the fall of 2011 when we have an upcoming yard period. They typically run somewhat lightly loaded, but they are regularly exercised accordingly. They've been great generators.

Let me clarify a few things. The manufacturer would have a much better idea of how long they would run before a major overhaul. There is nobody on this forum, besides you, that knows the history of the generators, how they are currently running, or anything other then a broad question of how long they should go between overhauls. For example, having a PTO for a bow thruster hanging on the front of the crankshaft would/could change their lifespan considerably. Oil samples would be a good indication, as would a compression test.

If Northern Lights says they will go 30k hours, then that is what I would tend to believe. Like I said, call Alaska Diesel in Pompano Beach, they are Northern Lights. My theory is that if they are running good, not leaking or burning excessive oil, and you have 2 of them, just maintain and run them until you have a failure and then rebuild them. Why fix something that isn't broken?