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colin loach

By colin loach
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barge sara Community Regular

barge sara

Posted
Posted

If you're giving it some throttle for any length of time, its the temperature gauge you need to be watching, not the rev counter.

A lot of NB's seem to have skin tanks too small to cool an engine that's working hard. Just keep an eye on the temperature and be prepared to slack off if it starts to overheat.

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bottle Veteran II

bottle

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Anything above your normal running temperature, :lol:

 

No seriously if the temperature starts to rise, ease off until it returns to 'normal'.

 

When engines start to overheat the temperature tends to keep rising, so be vigilant and keep checking.

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Rick-n-Jo Community Regular

Rick-n-Jo

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Posted
what temperture is to hot,

 

As soon as it starts to rise above where it normally sits.

The engine temp is normally set by the thermostat, which opens at that temp to let coolant around the external (skin tank etc) circuit. If the skin tank cannot dissipate the heat being delivered to it then the temp of that, and the engine, will continue to rise.

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steelaway Influencer

steelaway

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Hi all, Ihave a isuzu 42 engine, what is the safe amount of refs i can use for a long trip up the thames. on the canalsi run at 1200 but this is to slow on the thames. Thanks Colin.

 

 

Hi

 

How old is your boat? It would give us an idea of the size of skin tank, they have been fitting bigger ones recently

I think it is good to give canal boat engines a good thrash from time to time.

2000 rpm would be perfectly OK IMO, but do keep an eye on the temperature until you're confident all is OK.

85 - 90 degrees is about average running temperature. You should see rise and fall if the stat and tank size is all OK

 

Alex

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colin loach Collaborator

colin loach

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Hi

 

How old is your boat? It would give us an idea of the size of skin tank, they have been fitting bigger ones recently

I think it is good to give canal boat engines a good thrash from time to time.

2000 rpm would be perfectly OK IMO, but do keep an eye on the temperature until you're confident all is OK.

85 - 90 degrees is about average running temperature. You should see rise and fall if the stat and tank size is all OK

 

Alex

Thanks Alex that the answer i was looking the boat is 50ft 2008 liverpool built.

 

Hi

 

How old is your boat? It would give us an idea of the size of skin tank, they have been fitting bigger ones recently

I think it is good to give canal boat engines a good thrash from time to time.

2000 rpm would be perfectly OK IMO, but do keep an eye on the temperature until you're confident all is OK.

85 - 90 degrees is about average running temperature. You should see rise and fall if the stat and tank size is all OK

 

Alex

Thanks Alex that the answer i was looking the boat is 50ft 2008 liverpool built.

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alan_fincher Veteran II

alan_fincher

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85 - 90 degrees is about average running temperature. You should see rise and fall if the stat and tank size is all OK

I'm not sure I fully understand, if that's what you meant to say.

 

With a modern skin tank cooled engine, (or even quite an old one, like ours), the temperature on the gauge should rise until the thermostat temperature is reached, but, if the skin tank is up to spec, should not go higher even if the engine is pushed hard.

 

If your temperature gauge is accurate, and the thermostat operating at it's prescribed temperature, you should, (in my view!), never see the temperature gauge significantly higher than the thermostat operating temperature.

 

If you are, I believe it means the skin tank is not fully doing it's job, and water is being returned back into the engine that is not fully cooled.

 

Once you reach this state, (engine coolant significantly hotter than thermostat operating temperature), then your skin tank is on the margins of not coping. It will be dumping a bit more heat than otherwise, simply because water is coming "too hot" from the engine, and there is a bigger temperature difference to the canal or river water, resulting in heat being lost slightly faster - that compensates for it being "under sized" to a small extent, but gives little margin if you find you suddenly need to use a lot more power to extract yourself from a "situation".

 

I don't know the thermostat temperatures of modern engines, but they are seldom a lot over 85 degrees, so if your cooling water is going a lot hotter than that, you do not have a heap of reserve in the skin tank, (based on my own experiences of an inadequate skin tank).

Thanks Alex that the answer i was looking the boat is 50ft 2008 liverpool built.

I had always assumed that as a mass builder with so many boats to their name that Liverpool would have got basics like skin tank sizing correct.

 

However one or two previous threads on the forum have indicated that LB skin tanks are sometimes marginal (for the engine fitted), if pushed hard on rivers.

 

Some people have had success adding extra cooling, such as a fan playing on the inside of the tank.

 

My guess is that if you did try and punch figures like the 2000 RPM suggested for longish river slogs, you could well find the temperature rising higher than 90 degrees.

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Naughty Cal Veteran II

Naughty Cal

Posted
Posted
Are noddy boats any good at towing :lol:

 

They are better at towing than narrowboats are at keeping pace with cruisers.

 

In all seriousness though, trying to keep pace with a pair of cruisers in a narrowboat isnt going to do it much good. The cruisers will be at tickover and the narrowboat will be at almost full throttle.

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alan_fincher Veteran II

alan_fincher

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In all seriousness though, trying to keep pace with a pair of cruisers in a narrowboat isnt going to do it much good. The cruisers will be at tickover and the narrowboat will be at almost full throttle.

Yes,

 

But OP was about the Thames....

 

Whilst as a narrow-boater you might be left in a haze of that horrible white steamy smoke, as the "plastic" scoots away from a lock, you invariably see them again in the next lock, (frantically throwing out dangly fenders), as the lock keeper waits for the narrow-boats to arrive.

 

Very little evidence of the plastic getting along faster overall, when we did it, some of the time being spent on the "that's the tenth attempt I've had to throw this line over the bollard" ritual!

 

Several of the lock-keepers made it quite clear to us that they find the narrow-boaters easier to pack in and out quickly, and that they think they cause less hold ups.

 

Plus we can get under Osney bridge without knocking expensive bits off the top!

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WJM Veteran

WJM

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With a strong tide pushing you along, if you go too slow you will have no steering or control. I can put my boat into the mouth of Limehouse lock with total accuracy, but only by going to full (2200) revs on the final approach. Having watched a few ricocheting bouncers mess it up, the cause is simple, going too slow. You need revs and speed over the water to be safe.

 

On the tideway, it is temperature that you watch, revs are only the means of controlling temperature. My Isuzu runs comfortably at 1800 revs for hours on end, but I run the tideway at 1600 revs, just to leave some margin, not to over-stress things. In warm weather I put a 12v electric fan into the engine bay to draw air over the skin tank. If it is very hot, I wedge the engine bay cover open slightly to allow good airflow.

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Naughty Cal Veteran II

Naughty Cal

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Yes,

 

But OP was about the Thames....

 

Whilst as a narrow-boater you might be left in a haze of that horrible white steamy smoke, as the "plastic" scoots away from a lock, you invariably see them again in the next lock, (frantically throwing out dangly fenders), as the lock keeper waits for the narrow-boats to arrive.

 

Very little evidence of the plastic getting along faster overall, when we did it, some of the time being spent on the "that's the tenth attempt I've had to throw this line over the bollard" ritual!

 

Several of the lock-keepers made it quite clear to us that they find the narrow-boaters easier to pack in and out quickly, and that they think they cause less hold ups.

 

Plus we can get under Osney bridge without knocking expensive bits off the top!

 

You must have come across the annual outing :lol:

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nb Innisfree Veteran II

nb InnisfreeDonate to Canal World

Posted
Posted (edited)
Hi all, Ihave a isuzu 42 engine, what is the safe amount of refs i can use for a long trip up the thames. on the canalsi run at 1200 but this is to slow on the thames. Thanks Colin.

 

 

If you can achieve or nearly achieve max revs then you are not overpropped so IMO 2000rpm is fine providing skintank and temp is ok, I would be happier with 1800 rpm. Running engine harder than usual may result in a small increase in running temp, perhaps a degree or two but as long as it remains steady and there is no black smoke (i.e. not overloaded) all should be ok. Also oil temp will may rise a bit and therefore pressure will be a bit lower.

 

If you do run at 2000 rpm ease off for a while occasionally.

Edited by nb Innisfree
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Proper Job Veteran

Proper Job

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Posted

Don't forget that diesel engines (especially modern ones) like to be worked hard and hot.

 

Most of the time when running on canals they rarely get a chance to do any real work.

 

The engine will have a maximum continuous rating and peak rating (usually expressed in rpm or percentage of load). You should be able to run at the continuous rating all day every day (if conditions suit). Obviously that is subject to having sufficient cooling via the skin tanks.

 

The Isuzu 42 torque curve peaks at 1800 rpm. See what its like at that. You should have plenty more revs left if you need them though.

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