Engine upkeep

[alanporter]

I have a diesel engined sailboat which is afloat all year. In the winter, when the weather precludes taking the boat out, I like to run the engine at the dockside, with tight lines and in gear. Someone has told me that running for only a half to one hour is harder on the engine than not running it at all, and that it should be run for two hours or more to get it really hot. Are there any diesel mechanics out there who can advise me on this subject ? I don't need to run the engine for battery charging as I am plugged in to shore power. Many thanks

Alan Porter

 

[ean_p]

Oh No!!!!!!!!............

 

[bedouin]

Re: Oh yes!

Here we go again

I would recommend searching the archives for the discussion on the same subject about 2-3 months ago (a search for "glazing") should find it.

There was no agreement as to whether running the engine unloaded does long term damage or not. If you ensure that the engine gets to full working temperature each time, then everyone seems to agree that it won't do any harm.

 

[ccscott49]

As long as the engine reaches full working temperature, it will do it the world of good, you are doing the right thing, wraming it up under load, if it doesn't reach full working temperature in an hour, then check the thermostat, because believe me it should!

 

[pvb]

No problem...

If you're running it in gear, at reasonable revs (say 1500), then let it get up to working temperature for a while, it will do it nothing but good. I do the same with mine in the winter.

 

[PeterGibbs]

Re;Why do it?

Why do you put yourself through this hoop?

Winterising an engine in a floating boat by ensuring an oil and filter change in the autumn, and antifreeze in any water left standing in the cooing galleries, will see it happily through until spring.
Being in the water is not material vs all those who leave their engines, with suitable protection, all winter on the hard.

Running up does no harm if run to full heat, with or without load. Glazing is not a consideration for a well-used engine used as you describe - maybe 2-3 times per winter. But why do it?

PWG

 

[Avocet]

Re: Re;Why do it?

It depends a bit on how big the engine is. I have a very small (12hp single cylinder) diesel and I run it in gear for about half an hour at the most to warm it through and charge the battery. As long as the thermostat is OK and it reaches working temperature I think that's fine. There is an argument for making sure the oil is up to working temperature for a decent amount of time so that any unburnt fuel that has pushed past the piston rings gets a chance to evaporate out (otherwise the oil gets thin and looses its lubrication proerties) but I think 2 hours is a somewhat excessive. I mean, how many passages do you normally do where the engine is used for 2 hours? Even in the season mine gets used for about 15-20 mins at a time to get out of the harbour. I can't see many engine manufacturers telling you they won't honour the warranty unless its used for at least 2 hours every time you fire it up!

 

[kgi]

I agree with most of the posts BUT what you are trying to stop in the oil is emulsification, remember when an engine is switched off it inevitably cools an produces some condensation in the crankcase, if the engine is not run for long enough you are only compounding the problem, running the engine in gear for an hour puts a load on the engine and makes it work hard, in the process boiling the water off in the oil, if the engine is not run like this then you stand the chance of internal corrosion and the etching of bearings, rods, crank etc, to my knowledge at least two vintage aircraft were lost because of engines that had been inadequately, inhibited and internal components became etched and thereby failed causing the loss of both aircraft (but not the pilots)........its something to think about...keith

 

[trevor]

Why run the engine? My boat is in the water 11 months of the year and I never run the engine except when necessary.
If you took your boat out in the winter you would not be able to run the engine ashore anyway and from an engine point of view there`s no difference if its ashore or afloat (probably warmer afloat in really cold weather).
Trevor

 

[vyv_cox]

Good job we didn't go down the "glazing - does it exist" route again!

I agree with several other posters. Don't run the engine at all during the winter is the best advice. On the plus side is - what? Make sure it still runs? Why would it not? Charge the batteries? Take them home, or connect to the mains. On the negative side, you may increase wear levels through condensed acids. You may generate glazing (jury still out on this one) You will draw cold air into the fuel tank that will condense water over a period. You will fill the exhaust trap with water that will freeze and crack if sufficiently cold.

Best advice is change oil and filters at the end of the season. drain everything containing water that cannot be protected with antifreeze, fill the diesel tank to the brim, take out the impeller and leave it alone until next season.

My boat is afloat 12 months of the year but engine is out of commission December to March.