Synthetic diesel lube oil

[peterlewis19]

Sorry folks I must be missing the point. Oil with low numbers 1- 10 are for cold climates but once you start and run the motor it's not cold. The Fire brigades, all the world, use engine oil heaters so they start with a warm engine and no issues. I am an aero engineer but not marine. But a great friend of mine is the best - pain 10,000 USD per month proves it. When I brought my present boat I had a number of questions for him.
1. Q. I understand that synthetic oil is good for 300,000 K in a car or truck - should I use it in spite of cost?
A. Yes good forever! But! When a marine motor is not on full load or even load the compression is not designed to push the rings out full onto the bore to seal the cylinder. Consequently a lot of carbon blow by - ever noticed the black oil? Oil is cheap when it is black change it and your OK. The carbon destroys the oil - not age or miles! I run my motor at 1800 RPM at 6.50 Kn and every hour or so full continuous 2800 ( max 3200)
So as you can see 250 - 300 hours need to clean oil and filter. But cheap in my cae I can only extract 4 ltrs.

[a64pilot]

You really should change oil every 100 hours if your trying to make the motor last as long as is possible.
Your right about the carbon, but it’s not the oil it’s bad for, carbon is abrasive and if you run oil for 200 to 300 hours your circulating an abrasive fluid through your engine for a long time.
Now you can go 300 hours, for thousands of hours, well past the warranty period, but if your striving for 10,000 hours change it more frequently.

[Ballsnall]

Originally Posted by a64pilot

You really should change oil every 100 hours if your trying to make the motor last as long as is possible.

Sorry, this is just a wast of money and resources, 250hs is pretty much standard for any diesel engine with standard filtration and many modern diesels able to achieve 500hrs to 1000hrs with suitable filtration and that's using minerial oils. Your oil will turn black after just a few hours use indercating contamination of the oil, but this does not mean the oil is ineffective. If you want to increase your engine life, use a high quality oil changed regularly as per OEM, limit stop starts, warm engine before applying power and add additional filtration, both fuel & oil.

[a64pilot]

Well we have been down this road so many times it’s not worth going down it again, do a search if you like.
If you want extended oil change intervals use a good oil as you said, but install a high bypass oil filter.
Oil is cheap I just change it frequently and recycle it.

Your motor, you do as you want.

[Ballsnall]

Originally Posted by a64pilot

If you want extended oil change intervals use a good oil it.

Your motor, you do as you want.

We are not discussing extending oil change intervals, I only gave context to standard oil changes and what engine oil life is possible and still achieve full engine life.

You have given advice that 100hr oil changes will extend the life of the engine. This is absolutely false in any practical sense.

[a64pilot]

So, I figure Boat US are in collaboration with big oil, it’s a conspiracy right?
https://www.boatus.com/boattech/casey/changing-oil.asp

On edit, look it’s pretty simple the best the oil will ever be is when it comes straight out of the bottle, it’s doesn’t get better when it is used, in truth our little Diesels most of us never break an oil down, we just don’t stress the oil that much (most of us)
We change oil because it gets soot loaded, you determine how much your engine is worth to you, and your oil change interval. Many times if not most often the marketing dept has a big say in oil change intervals. If your selling an engine it’s a strong selling point if you can say well our engine due to its superior technology and closer tolerances only needs its oil changed every 300 hours, with out competitors engine you will be spending much more money with the mechanic changing the oil so often.
So long as it gets through warranty period and lasts a decent lifespan, that’s all a manufacturer cares about, but if you want your engine to last as long as possible, change the oil frequently, don’t save pennies on oil changes.

[Wotname]

Originally Posted by Ballsnall

Sorry, this is just a wast of money and resources, 250hs is pretty much standard for any diesel engine with standard filtration and many modern diesels able to achieve 500hrs to 1000hrs with suitable filtration and that's using minerial oils. Your oil will turn black after just a few hours use indercating contamination of the oil, but this does not mean the oil is ineffective. If you want to increase your engine life, use a high quality oil changed regularly as per OEM, limit stop starts, warm engine before applying power and add additional filtration, both fuel & oil.

And yet, Yanmar calls up oil change interval of 100 hrs (or two months) for it's 3YM30 which is a common current production small boat engine. A 100 hour interval seems common place for recreational boat engines AFAIK.

[Ballsnall]

Originally Posted by Wotname

And yet, Yanmar calls up oil change interval of 100 hrs (or two months) for it's 3YM30 which is a common current production small boat engine. A 100 hour interval seems common place for recreational boat engines AFAIK.

Absolutely, I would put my faith in the OEM recommend interval. In my experience, 250hrs is the standard recommended for the majority of diesels I have ever worked on. The smaller the engine the less oil capacity so they are generally changed more frequently, some even at 50hrs, but to suggest that more frequent oil changes over and above the OEM specs will increase engine life is incorrect. I run dozens of Cummins engines (OEM recommended change 250hr) which we have increased to 500hr and now 750hr intervals and looking at the feasibility of 1000hrs. This is to save money on oil & filters which is a substantial savings over the 24,000+ engine life we achieve. Engine life is critical and if changing the oil more frequently than the OEM suggests was beneficial then I'm sure a lot more companies would be doing it.

[sailorboy1]

If you really want your engine to last change the oil every 20 hours and the filter every 5 hours, or every 2 days. Whichever is less.