Synthetic engine oil...

[sheral]

Not that I like to stir up controversy, as this topic will, but how many owners have switched to a pure synthetic motor oil, and if you did, how many hours did your engine have when changing over?

I ask because even though the Volvo Penta manual says a pure synthetic oil is fine, there are many people who think that changing over to a pure synthetic shouldn't be done until the engine is broken in - and is broken in 250 hours, 400 hours, etc?

 

[workingdogs]

As a commercial pilot I can shed some light on the logic behind that . With air cooled piston aircraft engines , synthetic oil is universally not recommended for the break in period of the engines . The reason is that with the tight rings and loose tolerances, the engines needed the added friction of normal oil to wear down the very specific pattern of milling marks in the cylinder walls to create a better seal to reduce oil consumption in the long term . With the normal duty cycle of that kind of engine the cylinder heads would routinely see 400 deegrees , so the seal with the piston rings was critical because with the extreme expansion and contraction of the metals , the rings needed all the help possible in break in to have the best seal . After 50 or so hours or so , the much more slippery synthetic oils were ok to use since the beneficial wear had been able to occur with the less slippery , non synthetic oil .
The Diesel engines we all have are water cooled and the tolerances are very tight and no real break in wear is needed .
The cylinder heads do not come near the temps in an air cooled engine . Use the diesel synthetic Volvo recommends and worry not .

 

[Scuffy]

I run synthetic oil in our cars and do oil changes once a year. Usually 15 thousand miles or less. With the boat I don't really want stretch oil change intervals. I just use Volvo's recommended conventional oil and save my receipts. Rather than spend the extra money on expensive oil I choose to send oil samples and have them analyzed. Because I would choose to change oil a little more often in the boat and don't like throwing away $$ on more expensive oil. But there is no shame wanting the best for your baby. I would run the engine for about 50 hours on regular oil before switching over to synthetic. I have always done that in our cars anyway. In our tow vehicle which is a Duramax diesel I use regular Shell Rotella T diesel engine oil. Changing oil at 10 k miles is the norm. I like the idea of changing filters and oil on standard intervals. If I was trying to run extended intervals I would use synthetic. I would think it would be hard to wear out your boats diesel engine in your lifetime if routine service is done with conventional oil. But that's just me.

 

[sheral]

Thanks guys. Very good / logical advice. 🙂

Part of my desire to switch over is because of where we live and I have a drum of Rotella T6, which I run in everything else (gas and diesel engines). It would just make life a bit easier switching over to the T6 in the Ranger, at some point. We have 80 hours on it now - after two months - and will run a new change of the T3 for maybe one more season, just to be safe...

 

[Barry Cohen]

I use Rotella T6 exclusively. No issues that I can see.

I pay $22.00 for a gallon at Walmart. West Marine sells the exact same container for $42.00. Not sure how they get away with it.

 

[sheral]

...The Diesel engines we all have are water cooled and the tolerances are very tight and no real break in wear is needed . The cylinder heads do not come near the temps in an air cooled engine . Use the diesel synthetic Volvo recommends and worry not .

This is excellent advice, imho. I had heard that the older diesels did need a substantial break in period but that the newer ones did not. However, when speaking to people about this issue, I would also hear that 'all' diesels needed to be broken in.

So, I called the customer service desks at both Volvo-Penta today and Shell Rotella this morning. Both reps told me the same thing that workingdogs has noted above. Seems a lot of knowledge out there is dated. The Volvo-Penta rep even commented how the new diesels are not prone to 'wet stacking' like the older ones were, hence maybe our ability to troll with them and not run them at 80 percent load all the time...