Oil

[Sailfree]

I am aware of mineral oil, semi sythetic oil and fully sythetic oil. In most motorcar engines I get the impression that fully sythetic oil is better as it has better lubricating properties (also dearest). On the Yanmar stand the expert said you should not use it in their engines. Can someone educate me on why or point me in the direction of information/website called " Oil for Dummies"

Thanks - I would just like a better understanding.

 

[Sans Bateau]

You should of course get 'expert' advice, but:

I was told by a marine engine engineer not to waste money on expensive oil. That was applicable to my Volvo 2002/3. His view was that most marine engines are only marinised plant engines, in other word designed to work on concrete mixers. The original design was to be running flat out all day with little care, with oil if they were lucky! It was better to let the engine burn a little oil.

He also told me not to under rev the engine, he said that he sees more engines with glazed bores that have been treated 'gently' than those that are thrashed.

I change the oil regularly, using Shell Spirex (I think that is the name) it was the one he recomended.

 

[BobOwen]

I ran a Triumph Daytona motorcycle on fully synth from new for a few years. The starter motor clutch is a sprag type. It involves spring retained rollers "biting" into an outer race when engaged.

After two years use the starter clutch was shot. This involved a full engine strip down. On examination, there was no wear at all to the clutch. However, the spring that held the rollers in place was over stretched. Communication with Triumph revealed that full synth oil is so "slippy" that the clutch would sometimes bite and othertimes not. With the starter motor still spinning and the motor trying to fire, there was an erratic drive through the clutch which can cause it to snatch and stretch the spring.

I fitted a new clutch and spring and have run the motor since on semi synth as they recommended with no problems. I know of a number of other very similar instances with bike engines, that were cured by switching from full to semi synth.

I mention this to illustrate there can be problems with various mechanical parts with using this oil, besides the obvious. It doesn't always follow that the better the oil, the better for your motor. I guess there are similar considerations with the Yanmar engine.

 

[VicMallows]

Beer for breakfast:

But I found in Munchen it was a great start to the day, whether Weisbier or not!...and that was in the works canteen!.

Vic

 

[BobOwen]

Know exactly what you mean Vic. I was asked in a factory in Stuttgart if I fancied a cold drink one afternoon, which was welcome.

We strolled across to the vending machine and my friend pulled two cold cans out.........of G+T !!

 

[duncan]

Spirex? I have heard of Helix and RimulaX....the latter being designed for turbo tractors and, as such, recomended by the Yanmar agent for my 4cyl turbo Yanmar engine.

I will admit to using GTD Magnatec as, if it does what it says, it has to be good for little used marine powerplants!

Some detailed oil info here...... oil specs

 

[Sailfree]

I was told for my Honda Fireblade that fully sythetic oil was so slippery they have to slow the tickover down the first time it is used. I was also warned that it could cause problems with clutches that are immersed in the oil due to being so slippery. I also appreciate that our boat engines are often just marinised plant engines. While we don't "care" about plant engines they are used hard and frequently. Our marine versions are often not used for say 4 months.

If we want them to perform best, last the longest (my understanding is that fully synthetic oil coats the metal surfaces better and stays there the longest) and there is no oil immersed clutch why isn't the use of fully symthetic oil recommended?
I have also been told if the engine requires running in it achieves this better with ordinary oil as synthetic lubricates too well!

I really would like to learn more and sort out the facts from the opinions!
All advice greatfully received.

 

[ongolo]

What I know is this. In the deep mines of south africa, synth. oil was used from a certain time on. Because of the use of synth oil, the service intervalls were extended by a fator of three. But the diesel engines then got so dirty inside, that oil channels were blocked up and engines died.

Also, long time ago, it was explained to me, that certain additives in oil for diesel engines are designed to suspend the sooth particels and not let them out of suspension. Oil for petrol engines on the other hand, must form an emulsion to bind the condense water produced in the cold engine. That was actually from an old engineering manual, it made sense to me, but I have never found another reference to that.

Now if this was correct, can additives in a synth oil do the job? the experience in south africas gold mines would indicate not.

By the way, motor cycle clutches running in oil are "wet" clutches, but BMW had just like cars always a "dry" clutch. Dont know about the latest BMW motor cycles. They do weird thing now, these jerries.

I rather use a cheaper oil, and change it more often. I check the condition of the oil then, for particles in the filter and so have a diagnosis for the engine.

For what it is worth.

regards ongolo

 

[MedMan]

Have a look here for some good general information. Alternatively, put "More Than You Ever Wanted to Know About Motor Oil" into Google and the same article will come up on a dozen different sites, one of which may contain other information of help to you.

 

[ex-Gladys]

We are comparing apples with bicycles here. Triumph motorcycles say that if you use Mobil 1 MOTORCYCLE specific the service interval is extended from 3000 to 6000 miles. Modern motorcycle engines in the under 1000cc class produce loads of power per litre. A number of 600 cc engines produce 120-130 bhp. Yer average 2 pot diesel marine engine is a lot less stressed and produces 10-20 BHP. I suggest that the right answer is the right oil for the application.... Fully synth in a naturally aspirated diesel cement mixer engine is a waste of money.