Engine Pre-Lube kit

[sandy stone]

Originally Posted by a64pilot

Turning one over without fuel doesn't really pre lube well, reason is you still have high compression which loads the bearings.

Hmmm, never thought of that.

Originally Posted by a64pilot

However if you have decompression levers, then if the engine has sat a long time, it might not be a bad idea to turn her over with no compression until it gets oil pressure.

Good idea, thanks!

[model 10]

[QUOTE=a64pilot;2478625]Aren't a lot of the newer turbos center section water cooled?


Water cooled turbo's came first to the marine world some years ago. It's not often you get trickle up engineering.

[Neziak]

Many good points here - thank you. I am leaning towards the view that the small risk of catastrophic failure and consequential damage due to a leak between the engine and the accumulator outweighs the benefit of reduced wear.

If I leave my engine unused for 3 months at a time over the winter, what steps should I take before starting to protect it?

I usually let the engine warm up and cool down for 10 minutes before starting and stopping.

[Sailmonkey]

Originally Posted by Neziak

Many good points here - thank you. I am leaning towards the view that the small risk of catastrophic failure and consequential damage due to a leak between the engine and the accumulator outweighs the benefit of reduced wear.

If I leave my engine unused for 3 months at a time over the winter, what steps should I take before starting to protect it?

I usually let the engine warm up and cool down for 10 minutes before starting and stopping.

for three months......nothing much. There is a lot of equipment that sits even longer between periods of heavy use with no ill effect.

[LakeSuperior]

If you really want to do your engine a favor run a compatible full synthetic oil. I have been using Mobile Delvac I (not Mobile I) in my gasoline cars, boats, lawn mowers, and snow blowers for 35 years.

Using a full synthetic will do more for your engine than anything else you could possible do over the long haul.

https://mobiloil.com/en/article/car-...nventional-oil

Last time I picked up a couple gallons the guy at the distributor told me that they run Delvac I in all their fleet pickup trucks and they never change the oil, ever. They just add when needed. BTW, I am not recommending this approach.

[Dockhead]

[QUOTE=Guy;2478756]

Originally Posted by a64pilot

Aren't a lot of the newer turbos center section water cooled?


Water cooled turbo's came first to the marine world some years ago. It's not often you get trickle up engineering.

I thought all marine turbos were water cooled? Mine certainly is.

I had a Porsche Turbo automobile in the '80's whose turbo was cooled only by oil, but the whole engine was cooled that way, so it was logical. Otherwise, surely it would be weird not to water cool them, considering how much heat there is in the exhaust side?

[Dockhead]

Originally Posted by LakeSuperior

If you really want to do your engine a favor run a compatible full synthetic oil. I have been using Mobile Delvac I (not Mobile I) in my gasoline cars, boats, lawn mowers, and snow blowers for 35 years.

Using a full synthetic will do more for your engine than anything else you could possible do over the long haul.

https://mobiloil.com/en/article/car-...nventional-oil

Last time I picked up a couple gallons the guy at the distributor told me that they run Delvac I in all their fleet pickup trucks and they never change the oil, ever. They just add when needed. BTW, I am not recommending this approach.

We've discussed this before, but some lubrication engineers believe that synthetic oil in marine diesels is harmful. See:

https://bobistheoilguy.com/forums/ub...Number=1602459

https://coxengineering.sharepoint.co...htengines.aspx

I have not actually read anything from an actual professional in lubrication, that indicates that synthetic oil does anything good for boat engines. Probably the nicest thing I've read is that it doesn't do any harm, but is a waste of money, and I think that's minority view.

The reason why it is, at the very least, a waste of money, is because boat diesel oil has to absorb a lot of soot and acid. It's time to change the oil because of this, far sooner than the film strength starts to break down. So the possibility of extended oil change intervals offered by synthetic oil is simply not usable.

My advice is to always use exactly that oil, and nothing else, which is recommended by the maker of your engine. I doubt if you could know better, what your engine actually needs, than the maker does.

[LakeSuperior]

One of the key features of a synthetic is that all the molecules are basically the same length and have the same flash temperature. A standard oil is a mix of molecules sizes with a corresponding range of flash temperatures. The synthetics therefore have a much higher flash point. In standard oils the smaller molecules burn at much lower temperatures.


So imagine a film of oil spread by the rings on the cylinder wall. The synthetic will live further up the cylinder than the normal oil. In addition, there are less burn products that end up washing into the oil. Therefore, the synthetic stays cleaner longer, creates less impurities, and lubricates more of the cylinder wall. Also, the synthetics can absorb more of the operational impurities than normal oils.

Also, consider much higher film strength and a much flatter viscosity curve for the synthetics. Much better lubrication on cold starts (maybe not a big advantage for marine applications).

Most new higher end cars have synthetic oil specs. Maybe the marine diesel manufacturers haven't caught up.

From
More Than You Ever Wanted to Know About Motor Oil

"The synthetics offer the only truly significant differences, due to their superior high temperature oxidation resistance, high film strength, very low tendancy to form deposits, stable viscosity base, and low temperature flow characteristics. Synthetics are superior lubricants compared to traditional petroleum oils. You will have to decide if their high cost is justifed in your application. "

[hellosailor]

a64-
Not a myth, but real fact, at least back then.
A real rocket scientist (double PHD's in combustion engineering among his credentials) explained to us that when you start an engine, any engine, the shaft literally slams around in the bearings for at least three or four revolutions, hitting bare metal on metal, before any oil gets in there. They all rely on a thin film of oil to lubricate AND cushion during startup.
And the oils in the 1970's simply did not have good "thin film" cushioning properties. The film they left on the metals ran off pretty quickly after shut-down, so the bearings were naked when you started up. Pre-lube addressed that.
A major change came with synthetic oils, which are better at thin-film cushioning to start with, that is, because of the way they are made, the oil film is not pushed aside when the parts hit it. And, the film clings to engine parts much longer, so there's more oil film during a cold start, and the film itself cushions more.
How substantial is the change? Dunno, I'm totally out of date on that. But in the context of conventional motor oils--the issue still applies. Some of the old Grumman flying boats used to do this routinely, because calling a mechanic from mid Pacific before there were cell phones...You know, sometimes TLC ain't all bad.