Optimum Oil Level ?

[RichardS]

I have a Volvo MD2030.
I asked a Volvo marine engineer once, he advised to fill to half way on the dipstick, and to never fill above that. Given boats heel angle he said that model doesn't like too high an oil level.
If I add the handbook volume of oil, it fills way above the dipstick max line.

I have a cat so it doesn't apply to me but I'm wondering how often a monohull would be heeled over with the engine running?

Richard

 

[KellysEye]

>Are you being deliberately obtuse? The angle in question is of the crankshaft, not lateral. Most yacht engines installed with conventional prop shafts are NOT horizontal. Look in any yard.

When you said an engine is not horizontal you didn't mention whether it was side to side or front to back, I assumed side to side hence the comment. I would agree that engines are slightly angled from front to back but that has no relevance to filling with engine oil to the highest dipstick marking which is why said there is no problem filling to the highest level marked.

 

[macd]

>Are you being deliberately obtuse? The angle in question is of the crankshaft, not lateral. Most yacht engines installed with conventional prop shafts are NOT horizontal. Look in any yard.

When you said an engine is not horizontal you didn't mention whether it was side to side or front to back, I assumed side to side hence the comment. I would agree that engines are slightly angled from front to back but that has no relevance to filling with engine oil to the highest dipstick marking which is why said there is no problem filling to the highest level marked.

Funny, everyone else seemed to understand what was meant.
It most certainly has relevance. See the handbook quote in my post #16.
Clearly an engine must have sufficient volume of oi for lubrication and cooling. The other main issues are threefold:
1. allow sufficient free air volume remianing in the crankcase;
2. not to allow crankwebs to reach the oil level;
3. position of oil level relative to oil pump pick-up.
There is commonly a degree of latitude with the latter, since most engines likely to be placed in yachts are designed to be in devices which: a) go up and down hills; b)decelerate and accelerate; c) go round corners.

 

[ghostlymoron]

I would think that for the vast majority of sailors who've never even considered angle of engine installation, they would fill up to the Max level without any dire consequences.

 

[GrahamM376]

Over filling can cause a lot of damage, if conditions conspire against you. There are recorded cases of engine seizure due to hydraulic locking of certain components (thrust bearings iirc).

If the rotating crank churns the sump oil it can overheat, froth and lubrication can be lost. This is often more relevant to gearboxes.

Don't disagree that overfilling is a bad idea, mainly because excess oil can be forced past the rings but, your second point about the crank churning oil needs clarification. Most engine bores and little ends are splash lubricated which relies on the big ends dipping into the oil and splashing it up the bores.

 

[rogerthebodger]

Don't disagree that overfilling is a bad idea, mainly because excess oil can be forced past the rings but, your second point about the crank churning oil needs clarification. Most engine bores and little ends are splash lubricated which relies on the big ends dipping into the oil and splashing it up the bores.

Wrong at a point int the rotation of the crankshaft theoil hole in the crank lines up with a oil drilling on th con rod that will give a squrt of oil on to the lowerpoint of the bore and thus libricate the bore on small endbearing. The crank shaft must not dip into the oil in the sump as the foaming it will cause will damage the structure of the oil.

 

[GrahamM376]

Wrong at a point int the rotation of the crankshaft theoil hole in the crank lines up with a oil drilling on th con rod that will give a squrt of oil on to the lowerpoint of the bore and thus libricate the bore on small endbearing. The crank shaft must not dip into the oil in the sump as the foaming it will cause will damage the structure of the oil.

Suggest you do a Google on "Splash Lubrication" Plenty of articles such as this - http://www.marinediesels.info/Basics/lubrication_system.htm