Moving off with a cold engine

[RLWP]

I'd hope any decent engine had oil in the right places in about three or four seconds.

 

I don't understand your second point

 

Richard

Edited June 17, 2014 by RLWP

[nicknorman]

I don't understand your second point

 

Richard

Only applies to petrol engines I think, and old ones with accelerator pumps at that.

[bizzard]

Boats like aeroplanes don't progress with feet on the ground like motor vehicles but both are at the mercy of the elements and so its best to make sure your engine is warmed up a bit and running ok your before casting off. On still water canals its not so important but you still have the wind to contend with. The motto is. The first thing to do before casting off is start the engine. The last thing you do after a trip and are tied up securely is stop the engine.

[RLWP]

Only applies to petrol engines I think, and old ones with accelerator pumps at that.

 

Ahh, got it. Otherwise revving the engine throws oil up the bores from the bottom, improving lubrication

 

Richard

[Alan de Enfield]

When I wake up in the morning (which fortunately I have done every day - so far), it takes a couple of minutes to become 'compus-mentus', it would then takes a few more minutes before I would be ready to run a marathon (not that I could now anyway), I need a cup of tea, get the joints loosened up and get the blood flowing.

 

I treat my engine the same way (but not the cup of tea) - start it and let it get warmed up on tick-over for 5 minutes +, all the oil gets circulated and the metal warms up and expands towards where it should be.

Edited June 17, 2014 by Alan de Enfield

[Bod]

I'd hope any decent engine had oil in the right places in about three or four seconds.

 

I don't understand your second point

 

Richard

I was told that the great rush of unburnt fuel/air mix entering the cylinder, would at best dilute the oil layer on the cylinder wall, or wash it off completly.

By then stopping the engine, a new layer would not be spread around.

Admitley this was more for petrol engines, I would expect a diesel not to be as bad, due to injectors, rather than carberettors.

 

Having suffered for years a neighbour who reved to the red line, then switch off, before the revs fell, I did ask questions. (Basic answer, was I lived next to a prat)

 

Bod

[Timleech]

When I wake up in the morning (which fortunately I have done every day - so far), it takes a couple of minutes to become 'compus-mentus', it would then takes a few more minutes before I would be ready to run a marathon (not that I could now anyway), I need a cup of tea, get the joints loosened up and get the blood flowing.

 

I treat my engine the same way (but not the cup of tea) - start it and let it get warmed up on tick-over for 5 minutes +, all the oil gets circulated and the metal warms up and expands towards where it should be.

 

Usually it's recommended to get the engine warmed up quickly, and that involves putting some load on it.

It takes a lot longer to warm up with no load, and the most cylinder wear is likely to occur with a cold engine.

I would generally just give it half a minute or so for oil to reach all the right places, and then get going as soon as convenient though maybe not at full speed straight away.

As for stopping, if the engine has been working hard (not often the case on a narrow canal), then it is a good idea to run it with light or no load for a little while before turning off. If you've just been pottering along, don't worry about it.

 

Tim

[RLWP]

I was told that the great rush of unburnt fuel/air mix entering the cylinder, would at best dilute the oil layer on the cylinder wall, or wash it off completly.

By then stopping the engine, a new layer would not be spread around.

Admitley this was more for petrol engines, I would expect a diesel not to be as bad, due to injectors, rather than carberettors.

 

Having suffered for years a neighbour who reved to the red line, then switch off, before the revs fell, I did ask questions. (Basic answer, was I lived next to a prat)

 

Bod

 

It's a hang over from petrol engines with carburettors that had accelerator pumps. twisting the throttle caused the accelerator pump to shoot an impressive quantity of neat fuel down the air intake. This is what would wash the bores

 

Doing it once was OK, pumping the throttle is a bad idea

 

It's irrelevant on diesels, they don't work like that

 

Richard

[luctor et emergo]

Leaving an engine tick over before switching over is important if you have a turbo (hello NC ), because it loses its oil pressure when you swith the engine off. The turbo needs to stop before you switch off.

[Tony Brooks]

To add - especially if you have a turbo like NC and have been running fast. The turbo needs time to spin down and cool down while there is still an oil supply.

 

I think it is a case of horses for courses, especially on trad engines. I would never rev a stone cold engine but would start before casting off and then get some load on the engine asap to hasten the warm up. I suppose on a modern (no cold start button) diesel a fast warm up is not as important a son a petrol engine where there will be extra fuel about on a cold engine and that may/will help dilute the oil on the bores.

[RLWP]

I think it is a case of horses for courses, especially on trad engines. I would never rev a stone cold engine but would start before casting off and then get some load on the engine asap to hasten the warm up. I suppose on a modern (no cold start button) diesel a fast warm up is not as important a son a petrol engine where there will be extra fuel about on a cold engine and that may/will help dilute the oil on the bores.

 

The difference between an old and a modern engine is partly due to piston mass. Old engines were designed with the 'build 'em strong' philosophy and consequently the parts are hefty. Large pistons take longer to warm through

 

Modern engines are designed for reduced weight and efficiency, so they rev faster. To do this, you have more, lighter pistons which warm through faster. I suspect they are a closer match to the bore too

 

Most engines have aluminium alloy pistons in an iron cylinder. The aluminium expands more per degree than the iron, an engine is designed for running temperatures, when the piston fits the bore properly. When cold, the piston is significantly smaller than the bore

 

I suspect there will be something to do with oil technology in the mix too

 

Richard

[Naughty Cal]

To add - especially if you have a turbo like NC and have been running fast. The turbo needs time to spin down and cool down while there is still an oil supply.

 

I think it is a case of horses for courses, especially on trad engines. I would never rev a stone cold engine but would start before casting off and then get some load on the engine asap to hasten the warm up. I suppose on a modern (no cold start button) diesel a fast warm up is not as important a son a petrol engine where there will be extra fuel about on a cold engine and that may/will help dilute the oil on the bores.

Which it does in the time it takes to enter harbour, tootle over to the pontoon and moor up. There is little point in leaving it ticking over on the pontoon.

[Athy]

Most engines have aluminium alloy pistons in an iron cylinder. The aluminium expands more per degree than the iron, an engine is designed for running temperatures, when the piston fits the bore properly. When cold, the piston is significantly smaller than the bore

 

 

Richard

Cor, thanks, I never knew (or thought of) that. Could that be something to do with my engine being rather smoky when cold but running clear when nicely warmed up, the piston fits more snugly so the fuel is used more efficiently?

[John V]

I don't warm my engine up as such, as it takes about 20 minutes at tick over with no load before the gauge gets off the bottom stop.

 

I normally start up and then check over oil pressures, charge rate, gear lever etc cast off and go. once running

 

with a load it warms up quite quickly.

 

After reading this thread I thought I had better check the manual ( I've only had the engine 10 years so its probably about time)

 

been through it cover to cover and nothing!...reckon I'll just keep doing the same....

 

 

edit for fat finger

Edited June 17, 2014 by John V

[Androo]

I don't warm mine, or any boat I have had or moved. Sometimes if it's a really early start in a busy place, I will cast off and push out before starting engine so as to not disturb others.

On the BCN challenge, we managed to get Albion out of the arm we were on at 3am before starting engine. Catrin said she felt, not heard us go.!!

Very considerate indeed. Last week we had a narrowboat next to us who, started his engine at 5am. He left it running until 6.30am then decided to move on...what a B@@t@@d!!

[MtB]

The manual for REGINALD's engine says to warm it up for 15 minutes before applying full power (with a new engine), or just a few minutes when old and knackered. (Paraphrasing there )

 

MtB

[Hawkmoth]

I don't bother warming our engine before casting off because at first the load is light (I don't go to high revs straight away)

I think the thing about warming engines comes from 2 sources.

Old fashioned engines needed time to warm because the build quality was less (modern methods of manufacture). I was originally taught on tanks engines, modified Merlin engines, where we were told to warm them at about 1200 rpm until the temp gauge moved.

When I started flying light aircraft I was told the same, check temps and pressures before take off. ( you don't want and engine failure)

Todays boat engine is under stressed most of the time and doesn't need warming IMO.

Bob

[RLWP]

Cor, thanks, I never knew (or thought of) that. Could that be something to do with my engine being rather smoky when cold but running clear when nicely warmed up, the piston fits more snugly so the fuel is used more efficiently?

 

That is exactly right. Lower compression and more chance of oil getting into the cylinder means more smoke

 

Richard

[nicknorman]

I don't bother warming our engine before casting off because at first the load is light (I don't go to high revs straight away)

I think the thing about warming engines comes from 2 sources.

Old fashioned engines needed time to warm because the build quality was less (modern methods of manufacture). I was originally taught on tanks engines, modified Merlin engines, where we were told to warm them at about 1200 rpm until the temp gauge moved.

When I started flying light aircraft I was told the same, check temps and pressures before take off. ( you don't want and engine failure)

Todays boat engine is under stressed most of the time and doesn't need warming IMO.

Bob

On the aircraft thing, it is commonly taught at flying clubs to warm the engines for a significant time before taking off. However, if you actually read the engine manufacturer's manuals then, at least for Lycoming, it advises against warming up too much, merely warming until the engine can take full throttle without faltering. In temperate climates this is within a minute or so. We choose to follow the manufacturer's advice rather than the common practice in the UK and so far, our tug's engine (4cyl 6 litre air cooled lycoming of 1940s design) is nearly 50% beyond its overhaul life and still going strong (touch wood!). So the moral is that custom and practice often deviates from best practice over the years, but there is no need to be a sheep!

[Hawkmoth]

On the aircraft thing, it is commonly taught at flying clubs to warm the engines for a significant time before taking off. However, if you actually read the engine manufacturer's manuals then, at least for Lycoming, it advises against warming up too much, merely warming until the engine can take full throttle without faltering. In temperate climates this is within a minute or so. We choose to follow the manufacturer's advice rather than the common practice in the UK and so far, our tug's engine (4cyl 6 litre air cooled lycoming of 1940s design) is nearly 50% beyond its overhaul life and still going strong (touch wood!). So the moral is that custom and practice often deviates from best practice over the years, but there is no need to be a sheep!

What's that engine in? I've only actually tugged with Gypsy Major engine.

Bob

[Alan de Enfield]

What's that engine in? I've only actually tugged with Gypsy Major engine.

Bob

 

I used to Tug in an Auster which I seem to remember had the Gypsy Major 1 (130hp engine) bit underpowered really - particularly for 'open class' with full water ballast. We had constant problems with the undercarriage bungees collapsing - nothing to do with hard landings mind you !!

 

Then changed to a Citabria (G-BFHP) that if I recall had a 150hp engine and climbed like 'stink'

 

Happy days !!!!

[Hawkmoth]

 

I used to Tug in an Auster which I seem to remember had the Gypsy Major 1 (130hp engine) bit underpowered really - particularly for 'open class' with full water ballast. We had constant problems with the undercarriage bungees collapsing - nothing to do with hard landings mind you !!

 

Then changed to a Citabria (G-BFHP) that if I recall had a 150hp engine and climbed like 'stink'

 

Happy days !!!!

Yes they were. One of things I missed flying (on second thoughts maybe not) was that reputed stiff legged beast the Auster.

I'll bet 150 horses worked really well. I'm green with envy!

Bob

BTW As you were RAF did you ever fly from Bicester?

[Alan de Enfield]

Yes they were. One of things I missed flying (on second thoughts maybe not) was that reputed stiff legged beast the Auster.

I'll bet 150 horses worked really well. I'm green with envy!

Bob

BTW As you were RAF did you ever fly from Bicester?

 

I dont recall flying at Bicester - I was only a 'CI' (Civilian Instructor - not 'real' RAF) I did my'civilian' instructors course at Booker, PPL at Skegness ( 4 hour conversion from Silver C and 200 hours) tugging and all my personal gliding at Saltby (South of Grantham) MGPPL at RAF Syerston and teaching at RAF Newton

[Athy]

Old fashioned engines needed time to warm because the build quality was less.

Shurely shome mishtake here?

[nb Innisfree]

I make sure any engine I use is occasionally revved to just over its red line once it's up to tempto ensure the wear ridge is kept high enough up the bore just in case those revs are needed one day. Usually do it before turning off at the end of a cruise (I do let it idle for a minute or two before turning off.

 

I once bought a Wolseley 4/44 with 140,000 on the clock which had been driven gently all its life, along comes Stirling Moss in the guise of me who wanted to test its accelleration, result: shattered rings. The bloke who took it over stripped it down and showed me the old rings, all four were in pieces. Apart from that no damage and a set of ridge dodger rings sorted it. I realised later why it happened when I read of it in a motoring magazine.