Diesel engines have a great reputation for incredible longevity, yet most recreational marine diesels fail well before they should. The two primary killers are 1) overload (discussed at Diesel Engine Overload and Tony Athens’ Engine Life vs. Engine Loading) and 2) poor maintenance & operating conditions. Both are easy to avoid with a bit of knowledge, particularly overload.

On the second big killer, poor maintenance and operating conditions, it’s clear that a high quality scheduled maintenance program is a good investment. Beyond that I’ve adopted two simple techniques that have really paid off for me: 1) spend a bit of time with the engines, and 2) know your specific engine’s weaknesses and failure modes.

For the first one, just spend time in the engine room. If you know what it should smell like down there, what sounds are normal, and you frequently visually inspect, it’s amazing what you will find before it becomes a dangerous problem. From spending just 30 seconds in the engine room each day, I’ve found a variety of problems that could have become more serious. For example, the support bracket for the engine-coolant header tank broke once. At that point, the header tank was hanging from the hoses. If the hoses break or abrade, there is a good chance the engines will overheat, one of the quickest ways to shorten diesel engine life. Spotting this early means it’s a complete non-issue. In another engine room sniff, I smelled diesel. It never smells like diesel down there, so I looked more closely and found a fuel-tank vent-hose clamp had rusted through. If you keep the engine room clean and well lit, any leak from any component can be seen quickly. I’ve had several raw water pump failures, each of which was proceeded with a raw water leak at the pump seal (Changing the Raw Water Pump). Catching these problems early keeps the engines safe.

The second of my two simple techniques is to know your engines and their failure modes. This one also is incredibly easy. Find a forum where your engines are broadly discussed. For Cummins Marine, Boat Diesel is an excellent resource. From reading about your engines, you’ll start to learn the weak points and where a little extra attention is well worth paying. In the Cummins B-Series engines, I keep a close eye on the raw water pump and engine accessory-drive belt-idler pulley. Both fail more frequently than they should and warrant a bit more attention. I just posted a short article on checking the engine accessory drive belt and idler pulley: Belts and Idler Pulley.

James Hamilton

jrh@mvdirona.com

http://mvdirona.com

Those of us with recent Cummins engines (since they started using air preheaters) will notice that the factory alternators are actually pretty respectable.  My 2000 270Bs come with 105A Delco alternators. You would think this means I can charge at over 200A with the two installed in Dirona.  Well, it turns out that the 105A specification is more of a marketing number than an engineering specification.  Yes, they can produce 105A of output.  However, they can’t do this for more than a few minutes at a time, which is close to useless.  Now that we know that they can’t really produce 105A continuously, what can they do? 

Sometime back I wrote up an article investigating what charging rates can be produced continuously and reliably and how to achieve that number at minimum cost and hassle.  It was published in the May 2007 PassageMaker and we just put it up online at: http://www.mvdirona.com/TechnicalArticles/ChargingSystem.htm.  I’ve found that you can reliably get 70 to 80A and the alternators will run trouble free for years configured that way.  The article documents the investigation, discusses the limiting factors and shows how to configure your charging systems to get good results.

                                    --jrh

Snow fell in the Puget Sound this weekend as part of a big winter storm that swept the country. We were anchored at Port Madison, on the north end of Bainbridge Island, when the white stuff started. Even though the temperature was several degrees above freezing, snow began building up quickly. It was a wonderful winter scene.

Port Madison was a fitting locale for a snowy day in the Puget Sound. Bainbridge Island and Walt Woodward, editor of the Bainbridge Island Review, were the inspiration for local author David Guterson’s novel, Snow Falling on Cedars.

In the previous posting, Cumins Power Curves Confidential I talked about why having Power Curves for your specific engines is a good idea and why and argue it was a mistake for Cummins to not make this data available to customers. This data is now reported to be available. Apparently the Cummins folks I spoke with at 1-800-diesels were incorrect in saying the power curves were Cummins Internal Use Only and should have released them.  They directed me to PowerMaster@cummins.com who sent this letter explaining why customers don't need the data and that they were unable to release it due to corporate policy.  Apparently they were incorrect as well. Tony Athens and Etienne Grobler both followed up with Cummins and both were told the folks at PowerMaster and 1-800-diesels made a mistake. 

Etienne has approved me posting the letter they sent to him explaining the error: WaveMasterAtCummins.htm which offers more detail.  The good news is we can get the data we need (thanks for following up with Cummins Tony and Etienne). The bad news is there appears to e a surprisingly large number of folks in Cummins customer support willing to take a firm position with insufficient data. Nonetheless, I'm glad to see the power curves available to all. 

The updated article is at: http://www.mvdirona.com/TechnicalArticles/CumminsPowerCurves.htm.

--jrh

Since new, I’ve had the Cummins Performance Curves for my CPL 2205 engines but it was for a different rating.  Apparently the CPL 2205 engine was sold in a 260 HP Recreational  rating and a 225 Medium Continuous rating.  Sometime back I asked Cummins for the exact Performance Curve for my 270B (260HP Recreational) and was amazed when they said “sorry, we can’t get them to you, they are Cummins Confidential.” This is doubly weird in that 1) customers absolutely need this data to protect their engines and 2) the current generation Performance Curves are actually posted on their web site.

Their letter refusing to supply this data at: http://www.mvdirona.com/TechnicalArticles/CumminsPowerCurves.htm.  That page also gives an email address for you to send feedback to Cummins if you agree that not providing the data is bad for customer nor good for their business. Thanks,

                                                --jrh

James Hamilton, Windows Live Platform Services
Bldg RedW-D/2072, One Microsoft Way, Redmond, Washington, 98052
W:+1(425)703-9972 | C:+1(206)910-4692 | H:+1(206)201-1859 | JamesRH@microsoft.com

H:mvdirona.com | W:research.microsoft.com/~jamesrh