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Diesel engine warm-up


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You can all take the michael out of what I have written but at the end of the day, you know that I am right. The question of how to look after an engine has been answered.

 

Yes I am with you on that, aircraft engines are still piston engines (well some) and those principles still apply to us.

 

We're only having a bit of a giggle :lol:

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Where is the proof that one starting and running regime is better than another? Is it possible to take two identical engines and use them in different ways to come to any conclusion - maybe after a 20 year cycle - maybe after 50 years.....

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"Where is the proof that one starting and running regime"

 

Which do you prefer, the used car with 50k of motorway driving or the one with 25k of round town? (btw - the wheel rims usually give it away)

 

 

If I was going to replace my camshaft bearings, tappets, valves etc every six months I would just fire the thing up and speed off every time!

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Hi,

 

I'm trying to figure out what's the best practice for warming up a marine diesel engine? For how long? At what revs? Especially when you don't have a temperature gauge...

 

Thanks!

@

 

The generally accepted (and recommended technique in most car owners handbooks) is to start up and drive away as soon as you can with reasonable, and varying, revs (but not revving the whatsits off it). It is definitely not recommended to leave them idling. Engines only really warm up quickly under load, particularly the Gardner under consideration here (great lump of iron and gallons of coolant), so leaving it idling won't achieve a great deal. By the time that you've started the engine and udone the ropes/pins etc the oil will have been circulated adequately and that is sufficent. I must say that the Gardner 4LK that I had in Albion never needed any prolonged warming up and I was always able to increase the revs above idle as soon as I wanted to.

One way of proving/disproving Tony theory would be to do a comparison between a morning start when the domestic electrics have had a good bashing the evening before and another when they've hardly been used. If the engine responded normally to the throttle in the second instance and not in the first then Tony's theory will have been proven. If the engine won't rev in both cases then the cause of the problem is elsewhere.

Roger

Edited by Albion
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The operating instructions that came with my new Isuzu said that a cold engine should NOT be put under excessive load until it had warmed up.

 

In addition I don't agree that revving a cold engine hard immediatly after startup will splash oil around the top end any better than leaving it to idle. Even at idling the oil pressure is relatively high on startup and cold engine oil does not have the viscosity of molasses! It will be forced around all parts of the engine by itself very quickly.. Trying to speed up the process by revving hard merely increases the movement of cold moving parts and increases wear. .

Edited by blackrose
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The operating instructions that came with my new Isuzu said that a cold engine should NOT be put under excessive load until it had warmed up.

 

Yes, that's correct, 'excessive' load would be flogging the engine hard. Driving away with reasonable and varying revs is exactly the type of moderate load that will get the engine warmed up quickly and with the minimum amount of damage to the wearing parts.

 

In addition I don't agree that revving a cold engine hard immediatly after startup will splash oil around the top end any better than leaving it to idle. Even at idling the oil pressure is relatively high on startup. Revving it hard thus merely increases the movement of cold moving parts and increases wear. .

 

Agreed, you shouldn't rev a cold engine hard. The top end of an engine is fed by the pressure lube system (you'd have a job to 'splash' some up there) and by the time you've put your seat belt on and looked where you're going the oil will have circulated to all the pressure fed system and it's OK to drive off.

Roger

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As an Engineer this makes interesting reading.......... has anyone here taken an engine that has been thrashed from cold or left ticking over to 'warm up' apart and seen what it does to the movey up and downy roundy roundy bits? (pistons with the load face scratched to hell, goosed rings, big ends and mains with little or no white metal etc etc and not forgetting exhaust valves and stems choked in carbon.

 

Best advice is to go from cold keep to mid revs and don't labour the engine (i.e make it work unnessicarly (*sp) hard).

 

Have fun......... Untill you need a rebuild.

 

Sven

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Like so many threads on here, people are trying a "one size fits all" answer for all engines, even though all engines are clearly not the same.

 

I do however agree that for most normal canal and even river use, "normal use", hardly means "heavy load" or "thrashing it".

 

If you start the engine a minute or two before pulling the stakes out, and getting going, the best treatment you can give it is to set off sensibly, without flogging it. In general that is almost certainly "good" rather than "bad".

 

I am however, reminded that if you used to buy a car, you received all sorts of "running in" advice about not exceeding so many revs, trying to stick to a constant speed, etc. After a few cars, I was being told not to stick to a constant speed, and actually being encouraged to run them moderately hard. Standard advice does get re-written, as things evolve.

 

Some people have 1930s "vintage engines", some of us have 1970s automotive "van" engines, some have modern industrial based units. All probably need treating in broadly the same way, but there will be a degree of what is appropriate to an engine of that age, and built to a particular set of tolerances.

 

FWIW, this is what the BMC 1.5 and 1.8 litre Operator's Handbook states

 

Warming up.

 

Run the engine at a fast idling speed (approx 1,500 rev/min) until the engine attains its normal working temperature. Do not allow the engine to idle slowly.

 

Avoid prolonged idling or high no-load engine speeds.

 

Of course the one problem with that, in my marinised engine, is that if I "fast idle" at 1500 RPM, (recommended), then it sounds like I am at a high no-load engine speed, (not recommended). I don't think I'd in practice chose to leave it running at close to 1,500 RPM on no load, TBH, even though the book says do.

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"Where is the proof that one starting and running regime"

 

Which do you prefer, the used car with 50k of motorway driving or the one with 25k of round town? (btw - the wheel rims usually give it away)

 

 

If I was going to replace my camshaft bearings, tappets, valves etc every six months I would just fire the thing up and speed off every time!

 

That's no comparison at all - just too many variables. Firing up and speeding off is just what most people do in the mornings, it's usual to have the engine running in a boat before casting off so it's not quite the same. Most engines seem to outlast the vehicle these days so what is wrong with that?

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My one is a Barrus Shire 33 in a 42ft narrowboat.

 

Fire it up, undo your ropes, extract your pins, set off and enjoy your boating. You'll be kinder to your engine by giving it regular oil and filter changes with good quality oil than you ever will by worrying about the start up/idle-to-warm up regime. Your engine is based on a Yanmar industrial diesel engine. Industrial diesels have been developed to withstand hard use and abuse so your engine can take a cold start or two without wearing out. The industrial equipment that these types of engines are developed for certainly would not be molly-coddled in the morning, they would be expected to start work straight away.

HTH

Roger

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Fire it up, undo your ropes, extract your pins, set off and enjoy your boating. You'll be kinder to your engine by giving it regular oil and filter changes with good quality oil than you ever will by worrying about the start up/idle-to-warm up regime. Your engine is based on a Yanmar industrial diesel engine. Industrial diesels have been developed to withstand hard use and abuse so your engine can take a cold start or two without wearing out. The industrial equipment that these types of engines are developed for certainly would not be molly-coddled in the morning, they would be expected to start work straight away.

HTH

Roger

For the most part I agree although it is much the same for any engine rather than an industrial unit.

 

Unless you are going to use a pre-heater in the water jacket to heat the block through before starting there is little point in warming the engine up after starting it for a long time before moving off as much of the wear is in the starting process. However, the few moments between starting and getting underway are useful to help warm the engine a little and lose some tightness between components. Starting the engine with a high RPM setting is not going to help in this as as the engine starts there is momentarily not as much oil around the moving parts as normal running and high revs will expel what little you have and can cause high friction particularly as the block, crank and journals for instance are tight due to being cold. Just enough rpm to start the engine OK and gentle away when you are ready is the best you can do and as said timely and regular maintenance and oil changes will help the engine more.

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If I start my Izusu 42 from cold with cold water in the calorifier and drive away immediately it takes at least 20 minutes, maybe longer, for the temperature gauge to reach normal operating temperature of about 85 deg. If however I close the water valves from the engine to the calorifier, the engine is up to temperature in less than half the time, about 8 or 10 minutes. If I then open these valves the engine temperature falls back to about 75 deg and slowly returns to normal as the calorifier warms up which takes about a further 15 minutes. So on a completely cold boat the engine warm up period can be reduced by approx 50% by isolating the domestic hot water system until the engine is hot. Is that a good practice to adopt???

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If I start my Izusu 42 from cold with cold water in the calorifier and drive away immediately it takes at least 20 minutes, maybe longer, for the temperature gauge to reach normal operating temperature of about 85 deg. If however I close the water valves from the engine to the calorifier, the engine is up to temperature in less than half the time, about 8 or 10 minutes. If I then open these valves the engine temperature falls back to about 75 deg and slowly returns to normal as the calorifier warms up which takes about a further 15 minutes. So on a completely cold boat the engine warm up period can be reduced by approx 50% by isolating the domestic hot water system until the engine is hot. Is that a good practice to adopt???

 

I would have said so. In doing that you're doing basically the same job as the thermostat on a car cooling system. When the engine is cold, the thermostat remains closed, so that only a small amount of coolant is cycled around the engine. This then heats up a lot quicker than it would if all the coolant is used, and brings the engine up to temp quicker. When operating temp is approaching, the thermostat opens a gnats cock breadth, and begins to cycle all of the coolant. The engine is at running temp, and the coolant is close behind. HTH

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My old dad always told me as a kid it was not good to start an engine and then leave it idling - neither was it good to give it beans straight from the off.

 

I raced lawnmowers for many years where engines are particularly abused, having the governers removed and basically being stuck in a single gear, so really labouring coming out of tight bends and bouncing the valves on long straights. We had one guy who got through five engines in a single season - his running in technique was to put the engine on the bench and run it at 3/4 throttle (and no load at all) for a couple of tankfulls - then he'd race it. He also used to cane it straight from start up. His engines went bang at regular intervals!

 

The last new engine I bought - which was a Kohler, a type that had never been used for racing before, was run for a few minutes at varying revs on the bench, and then the oil changed. It then went on the mower and had a good hours running gently in the field - putting some loads on it but not really caning it. Every race day it would be started up and run for a few laps round the track fairly steadily before the racing started. That engine is around six years old now, has never broken down, has done a full season sprint racing each year and the 6 hour endurance race at the end of the season, and is as good as the day it went on the mower.

 

Interestingly, a read of a British Seagull outboard manual will tell you different, but there is a reason. They say you may be tempted to treat the engine gently while it is new, and this is basically the opposite of what you should do. It wants to go on a heavy displacement boat and be worked hard from day one. This is because the Seagull had been designed for the forces by all accounts, and they required absolute 100% reliability for a period of 24 hours non stop. I think they were for landing craft or something - so had to work hard for a short period, and then it didn't matter after that. As a result, all the bearing surfaces were massively over engineered for the size of the engine, and unless you gave it some stick, they would never bed in properly and reach the right clearances etc. Bit of a special case I'll grant you, but interesting to know!

 

Cheers,

 

Andy

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If I start my Izusu 42 from cold with cold water in the calorifier and drive away immediately it takes at least 20 minutes, maybe longer, for the temperature gauge to reach normal operating temperature of about 85 deg. If however I close the water valves from the engine to the calorifier, the engine is up to temperature in less than half the time, about 8 or 10 minutes. If I then open these valves the engine temperature falls back to about 75 deg and slowly returns to normal as the calorifier warms up which takes about a further 15 minutes. So on a completely cold boat the engine warm up period can be reduced by approx 50% by isolating the domestic hot water system until the engine is hot. Is that a good practice to adopt???

 

 

With reference to the above, a question for those that know.

 

Is it possible that the engine is 'plumbed' wrong and the calorifier should not be supplied until the engine has reached operating temperature?

 

If the engine is 'plumbed' correctly would a missing thermostat have the same effect?

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If I start my Izusu 42 from cold with cold water in the calorifier and drive away immediately it takes at least 20 minutes, maybe longer, for the temperature gauge to reach normal operating temperature of about 85 deg. If however I close the water valves from the engine to the calorifier, the engine is up to temperature in less than half the time, about 8 or 10 minutes. If I then open these valves the engine temperature falls back to about 75 deg and slowly returns to normal as the calorifier warms up which takes about a further 15 minutes. So on a completely cold boat the engine warm up period can be reduced by approx 50% by isolating the domestic hot water system until the engine is hot. Is that a good practice to adopt???

 

It does rather sound as if your calorifier is plumbed in before the engine thermostat and not afterwards but I'm not sure where the calorifier outlet is on an Isuzu, if it is engine mounted at all. Normally the thermostat would allow the engine to heat up to working temperature before opening. Then as the extra cooling from any other source circulates , be it calorifier or skin tank, the thermostat regulates to keep the engine at full temperature while the rest of the system is brought up to the same temperature. My great big lump of a Gardner 4LK didn't take 20 mins to warm up to full temperature on Albion so your more modern engine should do better than that. In the absence of any other fix your self-regulation of the calorifier valve is a good idea as the sooner you can get your engine up to temperature the better.

Roger

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You do need to exercise some common sense when following manufacturer's operating instructions, especially with older engines. For example, the manual for our Kelvin K3 states that if the engine has been left standing for a week or more, I should 'splash fresh oil over the cylinder bores, main and big end bearings before attempting to start it' this would involve partially dismantling the engine and is probably quite unnecessary with modern SAE30 oil which clings to the bores and bearing surfaces much better that its older predecessors would have done. Of course, the manual was written for operating the engines in the extreme conditions endured by Scottish fishing vessels and sea-going barges.

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You do need to exercise some common sense when following manufacturer's operating instructions, especially with older engines. For example, the manual for our Kelvin K3 states that if the engine has been left standing for a week or more, I should 'splash fresh oil over the cylinder bores, main and big end bearings before attempting to start it' this would involve partially dismantling the engine and is probably quite unnecessary with modern SAE30 oil which clings to the bores and bearing surfaces much better that its older predecessors would have done. Of course, the manual was written for operating the engines in the extreme conditions endured by Scottish fishing vessels and sea-going barges.

It is true that a straight mineral oil (without additives) will drain away from the engine more readily if left for a long period. However, the implication that the regime you suggest is because of the cold isn't necessarily correct. The colder it is the thicker the oil will be and the slower it will flow and fall away from the bearings etc. This "drying out" of bearings would happen faster in a warmer climate not a colder one although it may be slightly longer (because of the thicker oil) before the pump picks up the oil in the sump when it's colder.

 

One of the advantages of the additives that some people like to run shy of for canal engines is that it sticks to surfaces and clings on a lot better. However, API CC grades have little in the way of additives but they will help. API CF for example has much better clinging properties.

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With reference to the above, a question for those that know.

 

Is it possible that the engine is 'plumbed' wrong and the calorifier should not be supplied until the engine has reached operating temperature?

 

If the engine is 'plumbed' correctly would a missing thermostat have the same effect?

Interesting question !

 

My understanding, before I put a calorifier in, was that it should intentionally bypass the engine thermostat, so that the domestic water heats as fast as possible, without waiting for engine thermostat temperature to be reached, (and even then competing with the skin tank for the heat).

 

The rationale is similar to a car heater or van or lorry cab heater.

 

That's what I went for, so I'll admit my calorifier is slowing engine heat up from the moment the engine is started.

 

That said, the bits that companies like Calcutt and AMC supply as marinisation parts, are designed to attached to the engine so they do bypass the stat.

 

Am I killing my engine faster than before I added the calorifier ? Possibly ??

 

I'm confused !

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Interesting question !

 

My understanding, before I put a calorifier in, was that it should intentionally bypass the engine thermostat, so that the domestic water heats as fast as possible, without waiting for engine thermostat temperature to be reached, (and even then competing with the skin tank for the heat).

 

The rationale is similar to a car heater or van or lorry cab heater.

 

That's what I went for, so I'll admit my calorifier is slowing engine heat up from the moment the engine is started.

 

That said, the bits that companies like Calcutt and AMC supply as marinisation parts, are designed to attached to the engine so they do bypass the stat.

 

Am I killing my engine faster than before I added the calorifier ? Possibly ??

 

I'm confused !

 

It does seem to be the standard arrangement, having the calorifier connected before the stat, & I've always felt it was poor practice. A few engines have two stats, one before the calorifier/auxiliary heating connection and one after. This is the ideal arrangement, apart from there being one more thing to potentially fail.

 

Tim

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You do need to exercise some common sense when following manufacturer's operating instructions, especially with older engines. For example, the manual for our Kelvin K3 states that if the engine has been left standing for a week or more, I should 'splash fresh oil over the cylinder bores, main and big end bearings before attempting to start it' this would involve partially dismantling the engine and is probably quite unnecessary with modern SAE30 oil which clings to the bores and bearing surfaces much better that its older predecessors would have done. Of course, the manual was written for operating the engines in the extreme conditions endured by Scottish fishing vessels and sea-going barges.

I think that's a very early example of getting out of warranty issues on bearing pick up :lol:

 

Average Scottish fisherman to Kelvin man, "my bearings have picked up and I need new mains, big ends etc"

Mr Kelvin man, "have you followed our start up instructions for 'splashing it all over' (apologies to Henry Cooper) before starting the engine from cold?"

Average Scottish fisherman, "I'm a Scottish fisherman"

Mr Kelvin man, "Oh dear - never mind. That'll be two and a tanner for new bearings etc"

 

I should be a playwright :lol:

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With any petrol/diesel engine, you should give it several bursts of acceleration immediately after it fires up. This is to ensure the top of the engine is flooded with lubrication. Firing up and letting it immediately settle to low revs can leave the various high-up bearings dry because the oil is still very thick and the oil pump will not be providing much pressure to drive the oil around. So splash your engine with oil the second it fires up!

 

Unless of course it's an old fashioned carburettor jobby, in which case the unburnt fuel in the over rich mix will actually wash away the all important cylinder lubricant !

 

Mike.

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