Boat with twin Cummins 5.9's

Messages
150
Location
Cleveland, OH
Hey guys. It doesn't seem the marine section gets many looks, and these 5.9 hpcr engines (qsb 425's)are pretty simliar to the engine I have in my Dodge. I just picked up a boat over the winter that has twin cummins 5.9's rated at 425hp. They have 3.5gals of oil capacity and the boat stays in the water all season. A typical season here on lake erie is 5-6 months and a few hundred engine hours. Considering the cost of the boat, or even one 350gallon fill up of fuel, I do not care about the cost of the oil, I want to use the absolute best oil for the application in terms of protection, resistance to oxidation, etc. Recommendations?
 
Messages
18,449
Location
East of IGO
First define Best. Then what does the manufacture recommend? Add this to the mix . From my experience maritime operators use conventional HDEOS in their automotive type engines .
 
Messages
990
Location
Louisiana
Two 5.9 Cummins ISB's on a boat....WOW. Ok, now that I've picked myself off the ground let me make my signature statement....run any oil based on the Cummins recommended API spec (in your case it will either be a CI-4+ or CJ-4 spec) and you will be perfectly fine. Any of the popular HDEO oils will protect your investment admirably (Delo, Rotella, Delvac, Amsoil, Castrol Tection, Quaker State, etc.). A syn oil is by no means a requirement and I'll only recommend a syn oil in extreme environments (extremely hot EGT apps and extreme cold weather cranking). The average user just won't reap the extreme environment condition benefits that a syn oil has to offer. On top of that, take a look in the Used Oil Analysis diesel section here on BITOG. You get no wear reduction benefits from a syn -vs- a DINO HDEO.
 

dnewton3

Staff member
Messages
8,459
Location
Indianapolis, IN
Darn - beat me to it, Arka. 2x the above. I'll add this; your OCI duration will greatly effect your lube selection. All the oils Arka listed are outstanding and capable. If you want to greatly extend your OCI, then the synthetics might offer some advantage. However,, you didn't state what the OEM OCI is, so we're a bit blind here. If you're only going 300 hours or so for the whole season, that's not really that long. And, if it's 3.5 gallons PER ENGINE sump capacity, that's huge! I'd also add that some companies (Mobil, Amsoil, etc) even make marine specific oils, but they are often geared towards salt-water applications, which does not mean much in fresh-water lakes.
 

PT1

Messages
5,746
Location
near the mistake
This should be your OCI interval. Personally, I would do 200 hours or one season making sure to change oil in the fall prior to layup. You might wish to invest in an electric oil change system if it doesn't have one with those volumes. Much easier than a fluid extractor. Interval - 250 hours or 6 months Repeat Daily and 125 hour checks Change engine oil and filtersCheck/correct antifreeze concentration (%)Check/Inspect sea water pump/impellerReplace fuel/water separator elementReplace fuel filter (engine mounted)Maintenance(QSB example shown) Which model Sea Ray is it? FWIW, I would go with Chevron Delo or Mobil Delvac. Whichever weight Cummins specs. Probably 15w40 or 40w
 
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Messages
6,388
Location
Washington St.
 Originally Posted By: Lightman
I want to use the absolute best oil for the application in terms of protection, resistance to oxidation, etc. Recommendations?
Well, the regular price best oil is likely the Conoco/Phillips/76/Kendall new diesel lube oil with their exclusive Liquid Titanium. According to an article in the latest "Lubes & Greases" trade magazine, it really works to reduce some engine wear. The oil I'd choose is either Schaeffer syn blend 15W-40 or full syn 5W-40. Either would excel in meeting your needs for the best in engine protection and resistance to oxidation. Do try oil analysis. Buy a Vampire pump to extract oil samples, say every 100 hours until you develop a baseline, and see what your results are. Schaeffer offers very low cost analysis if you buy their product.
 
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