Engine proper temperature before shutting down

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cmedsailor

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In the absence of a coolant temperature gauge, how do I ensure that the engine has reached normal temperature before shutting down and hoist the sails? Is there a rule of thump? I will warm up the engine by starting, leaving the marina and slowly reaching cruising rpm (75-80% of full throttle) but then for how long do I need to run it at these rpm? Engine is a volvo penta d2-75 (turbo charged) if this matters?
Thanks
 
You need to make sure that the oil is hot - and that takes longer than water to heat I think.

Also, do not shut down a Turbo charged engine if the turbo has been running hard as it stops without dissipating the extreme heat, burns the oil in the barings and eventually buggers the Turbo - Idle for a few minutes before shutting down.
 
Chris_Robb said:
You need to make sure that the oil is hot - and that takes longer than water to heat I think.

Also, do not shut down a Turbo charged engine if the turbo has been running hard as it stops without dissipating the extreme heat, burns the oil in the barings and eventually buggers the Turbo - Idle for a few minutes before shutting down.
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True, and there's 9L of oil and it's right at the heart of the engine; 30L of water in the calorifier which is indirectly connected via heat exchangers and several feet of uninsulated hose, and is cooled by the seawater as soon as the thermostat is open. So I figure once the water is scalding, the oil is too...?

Delighted to learn if that's still wrong and there's a better way ?. PS mine isn't a turbo.
 
Trying to think what the consequence is of shutting down after 5 minutes. I would expect bores to be warm enough to avoid condensation of moisture in exhaust gases. Sulfur is so low now that sulfurous/sulfuric acids are almost negligible. A few other weak organic acids may be present but these mostly require high temperatures for generation. So overall I doubt there are any serious consequences in shutting down cool.
 
Some diesel cars seem to do numerous short journeys without getting that hot yet still manage to achieve high mileages. My previous diesel car did a huge amount of 2 mile journeys yet was still a really good engine at 273, 000 miles.
As above, can't really see an issue.
 
My last boat had a turbo engine, and after arriving in my berth in the marina, I always left it idling while I fiddled about with mooring lines and fenders, to give it 5-10 minutes to drop to a reasonable temperature.
 
duncan99210 said:
When using the engine, I get it running prior to slipping lines or hauling the anchor. I turn it off when I’m ready to hoist the sails. Never worried about how hot it gets
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Same here. Even more so, if the wind’s in the right direction for me to sail up the river then the engine might be on for literally two minutes as I furl the jib at the mouth of my aisle of the marina and motor about 50m into my berth. Half the run time will be while I’m getting the warps on.

I don’t have a turbo, though.

Pete
 
pvb said:
My last boat had a turbo engine, and after arriving in my berth in the marina, I always left it idling while I fiddled about with mooring lines and fenders, to give it 5-10 minutes to drop to a reasonable temperature.
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But would the turbo actually have been operating when you were doing close quarters manoeuvring in the marina? Even if you had been flat out until you approached the marina, would it have not cooled down for 5 or 10 minutes while you were at low speed.

I'm not criticising, just curious. (I doubt I'll ever have to worry about a turbo.)
 
LittleSister said:
But would the turbo actually have been operating when you were doing close quarters manoeuvring in the marina? Even if you had been flat out until you approached the marina, would it have not cooled down for 5 or 10 minutes while you were at low speed.

I'm not criticising, just curious. (I doubt I'll ever have to worry about a turbo.)
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The marina I'm in has a fairly long dredged entrance channel, then a lock. I'm particularly annoyed by the way that people dawdle up the entrance channel, as if they have all the time in the world, whilst there are people inside the marina itching to get out. So I make a point of always motoring flat out up the channel, to minimise the lock turnaround time. A couple of minutes in the lock helps the turbo cool down, but leaving it idling in the berth always seemed like a sensible idea. My current boat doesn't have a turbo, but I do the same thing.
 
pvb said:
The marina I'm in has a fairly long dredged entrance channel, then a lock. I'm particularly annoyed by the way that people dawdle up the entrance channel, as if they have all the time in the world, whilst there are people inside the marina itching to get out. So I make a point of always motoring flat out up the channel, to minimise the lock turnaround time. A couple of minutes in the lock helps the turbo cool down, but leaving it idling in the berth always seemed like a sensible idea. My current boat doesn't have a turbo, but I do the same thing.
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Sounds like Shotley! I used to be based there. My current boat is somewhat over-engined, so I used the entrance channel on the way in to give the engine a good blast at near WOT, but a bit gentler on the way out (or if I haven't had the engine on long on the way in) when the engine wasn't up to full temperature. I agree don't dawdle.
 
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I wouldn't worry about turning it off before it's hot.

I don't bother making sure mine's warm before turning off. The way I see it is that most of the wear is when the engine is cold and warming up, but once it's started up it's suffered some wear already and running it longer doesn't reduce the wear.

Perhaps two out of five times I'm going to be motoring for anything from an hour to several hours and it gets up to temperature, so if it never gets really hot the other three times it doesn't matter much. But I don't run it at tickover more than I have to, so when I'm motoring away from moorings etc I run it at about 75% max continuous revs.

About once a season I run it for 10 to 15 minutes at full throttle as advised in the Yanmar manual.
 
I was worried about my cooling water circulating so I bought an infrared thermometer to read the temperature of the raw water pump compared to the cylinder block. An engineering one was quite expensive so I bought this Amazon Sign In which now does double duty when not boating, sitting in the kitchen ready to check the temperature of things. Particularly useful when checking if reheated coffee coming out of the microwave is going to skin your lips or be drinkable.
 
johnalison said:
Not very scientific, but I put my hand on the top of the engine, and if it's hot, it's hot.
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Where Turbo chargers are concerned, they say you should be able to put your hand on the water jacket of the turbo for a few seconds. If you cannot, you need to investigate - normally due to an airlock. If your Green Turbo has turned black then I would investigate!
 
I had the impression that it was necessary to get the engine hot and running for a bit at high load to avoid glazing of the cylinders, maybe not every time but once in a while if there has been some low speed running.
 
scrambledegg said:
I had the impression that it was necessary to get the engine hot and running for a bit at high load to avoid glazing of the cylinders, maybe not every time but once in a while if there has been some low speed running.
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To avoid glazing you need to warm the engine up as quickly as possible. Condensation of exhaust gases on cold bores is a cause of glazing, much less of a problem than it was. There is a page about it on my website.
 
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