Jump to content

Engine temperature


Nemysys

Featured Posts

You may have seen my previous posts about ‘no hot water’, this has been answered and resolved (thanks Tony Brooks). insufficient engine coolant for the engine and calorifier.


All temperatures quoted below are based on the analogue gauge. 

I have a BMC 1.8, following topping up the coolant, the engine seems to be running at about 65 degrees.I’m sure before i topped up the coolant, it was about 80 degrees.
 

what is the correct running temperature for an engine?

I know this will vary per engine, just looking for a guide.

 

can an engine be damaged by running too cool?


I have booked in for a full engine service, so all should be sorted then, but I like to know and learn for future.

 

thanks

 

 

Link to comment
Share on other sites

Ideally the hotter the engine runs within reason the more efficient it will be. Certainly between 80 and 90 degrees would be a realistic target, I think the standard thermostat is 82 degrees.

However I would advise that you use an infra red thermometer, temperature gauges are notoriously inaccurate.

 

You also need to allow for the fact that normally the engine is very unstressed, consider the temperature likely to be achieved when flogging for hours against a fast flowing river or tide.

Link to comment
Share on other sites

31 minutes ago, Tracy D'arth said:

Ideally the hotter the engine runs within reason the more efficient it will be. Certainly between 80 and 90 degrees would be a realistic target, I think the standard thermostat is 82 degrees.

However I would advise that you use an infra red thermometer, temperature gauges are notoriously inaccurate.

 

You also need to allow for the fact that normally the engine is very unstressed, consider the temperature likely to be achieved when flogging for hours against a fast flowing river or tide.

Yes, buy yourself an infrequent red thermometer. Far more accurate.

Our engine runs at high 70's under normal pootling conditions, as measured on the hot bits at the top of the engine.

Link to comment
Share on other sites

10 hours ago, Nemysys said:

You may have seen my previous posts about ‘no hot water’, this has been answered and resolved (thanks Tony Brooks). insufficient engine coolant for the engine and calorifier.


All temperatures quoted below are based on the analogue gauge. 

I have a BMC 1.8, following topping up the coolant, the engine seems to be running at about 65 degrees.I’m sure before i topped up the coolant, it was about 80 degrees.
 

what is the correct running temperature for an engine?

I know this will vary per engine, just looking for a guide.

 

can an engine be damaged by running too cool?


I have booked in for a full engine service, so all should be sorted then, but I like to know and learn for future.

 

thanks

 

 

 

Many direct raw water cooled engines ran with thermostats of between about 65 and 75C to help prevent the hot spots inside the engine furring up with scale too much.  Even the ex vehicle engine designed did not seem to suffer too much.  Also some marinisers fit or have fitted 75C thermostats so the calorifiers can not delivers such dangerously hot water.  I think Calcutt did this on some of their engines so who marinised your 1.8. Nowadays it is more usual to fit a blending valve on the calorifier outlet so you can run your engine hotter.

 

As you have been running it with insufficient coolant for an indeterminate time you may have had air in the top of the skin tank and if you bled this out or it bled itself out you will have increased the cooling area. Running like that might have caused an overheat and some thermostats clip themselves fully open if they are overheated so that is a possibility. If you have not bled the skin tank please do it now and top up the coolant.

 

I agree that electric temperature gauges are far from accurate so an infra red thermometer allows a more accurate check.

 

Vehicle 1.8s tend to use a 88C stat, keel/tank or indirect cooled marine 1.8s usually run with a 82C stat unless a lower one has been fitted by the mariniser.

 

How long did you run for? I suspect your calorifier coil has been partially air locked for a while and this would decrease the amount of heat transferred to the hot domestic water so the engine got to running temperature faster. To be sure about your present running temperature I would want to run the engine of load for at least an hour and under load for at least half an hour.

 

 

PS I would not do anything until you have had a chance to give it a thrash on a river, far too many narrowboats have undersized skin tanks so tend to overheat when pushed and many people fit a cooler thermostat to hide the problem ------------ for a short while when running hard.

Edited by Tony Brooks
Link to comment
Share on other sites

Thank you. Yes it was marinised by Calcutt.

the engine was run on idle for about 2 hours.

 

I have emailed the marina anyway asking to be booked in for an engine service. It is well over due. I mentioned the temperature, they will know better than I.

 

as I’m sure it is obvious, I’m not clued up on engines.

Link to comment
Share on other sites

2 hours ago, Nemysys said:

Thank you. Yes it was marinised by Calcutt.

the engine was run on idle for about 2 hours.

 

I have emailed the marina anyway asking to be booked in for an engine service. It is well over due. I mentioned the temperature, they will know better than I.

 

as I’m sure it is obvious, I’m not clued up on engines.

That is bad for the engine and not conducive to getting a fast warm up to running temperature. It may still have been heating the calorifier.

 

Things are a but different now we have lots of solar but now its still darkish at 6 am any solar would not have added much to the overnight charge. Also not so good if you have shoreline charging running 24/7.

 

The bets way to charge batteries and heat water is to set the engine speed, out of gear, to that which the charging current will not go any higher. This may well be 1200 to 1500 rpm on a modern engine depending upon the state of battery charge. Then every 15 minutes or so check the charging current that will eventually start to fall and reduce the speed to maintain whatever the maximum charging is at that point. Eventually you will get to idle. This uses the alternator to provide as much load on the engine as possible so gives the fastest warm up. Diesels prefer to run under load and some tend to smoke on idle.

Link to comment
Share on other sites

14 hours ago, Dr Bob said:

Yes, buy yourself an infrequent red thermometer. Far more accurate.

Our engine runs at high 70's under normal pootling conditions, as measured on the hot bits at the top of the engine.

I am not convinced that infra red devices are good enough to measure engine temperature. Next time I run the engine (*)  I will do a back to back test with my infra red thingy and the thermocouple I have put in the cylinder head.

 

If you choose a dedicated spot or two then you could tell if the engine was colder than yesterday, or not up to temperature, but dunno if you would get a good absolute measure.

 

(*) just upgraded my 20 year old solar panels so no longer need to run engine everyday ?

 

..............Dave

Link to comment
Share on other sites

The book of words that came with my Perkins 4108M gives a temp of 75oC for raw water cooling, 90oC for skin tanks. Following Tony's comments about raw water furring up, when you have a Bowman heat exchanger cooled by raw water I can't understand why there should be a difference.

Link to comment
Share on other sites

2 minutes ago, Ex Brummie said:

The book of words that came with my Perkins 4108M gives a temp of 75oC for raw water cooling, 90oC for skin tanks. Following Tony's comments about raw water furring up, when you have a Bowman heat exchanger cooled by raw water I can't understand why there should be a difference.

Its not indirect raw water (Heat Exchanger) cooling that will fur up but direct raw water cooling where the raw water circulates through the engine. However any we exhaust boat is likely to eventually fur up its exhaust mixing elbow but that is not what we are discussing.

 

Furring will take place in an indirect raw water cooled system and keel/tank cooled engines but as once the lime/salt has been deposited there is no more in the coolant so the furring never gets to problem proportions. This is one reason some advise using distilled/deionised water in cooling systems.

 

Inside the engines there re certain spots like around the exhaust valve seats, pre-combustion chambers, and possibly around the injector nozzle area that have to get rid of far more heat than most of the internal areas of the engine. this means they run hotter so to stop these areas boiling (and consequentially furring up) we pressurise the cooling water to raise the boiling point. That is far more difficult to do on direct raw water cooled systems so they tend to run with a lower coolant temperature. Because the amount of heat transfered depends upon the temperature difference the cooler you run the engine compared with the hot spots the more heat is transferred to the coolant so the hot spots are less likely to suffer localised boiling.

 

On canals it is very unlikely any engine would suffer localised boiling so pressurisation is probably not so vital --- until you get on a river with a bit of flow.

Link to comment
Share on other sites

5 hours ago, dmr said:

I am not convinced that infra red devices are good enough to measure engine temperature. Next time I run the engine (*)  I will do a back to back test with my infra red thingy and the thermocouple I have put in the cylinder head.

 

If you choose a dedicated spot or two then you could tell if the engine was colder than yesterday, or not up to temperature, but dunno if you would get a good absolute measure.

 

(*) just upgraded my 20 year old solar panels so no longer need to run engine everyday ?

 

..............Dave

 

We used to usec ones with a valid certificate of calibration for commissioning standby diesel generators.

 

The cheapo one from I have from ebay is within 1.5°C when pointed at a black pan containing boiling water.

 

I point my IR thermometer at the top hose when measuring engine temperature.

Edited by cuthound
Clarification
  • Greenie 1
Link to comment
Share on other sites

Just now, cuthound said:

 

We used to usec ones with a valid certificate of calibration for commissioning standby diesel generators.

 

The cheapo one from I have from ebay is within 1.5°C when pointed at a black pan containing boiling water.

But at what altitude?

Link to comment
Share on other sites

5 minutes ago, cuthound said:

 

We used to usec ones with a valid certificate of calibration for commissioning standby diesel generators.

 

The cheapo one from I have from ebay is within 1.5°C when pointed at a black pan containing boiling water.

That's a scientific experiment, not a real world measurement ?

 

I.R. thermometers measure infra red emission, not temperature. Do I point the thing at my green painted engine, a black rubber hose connection, or a copper pipe containing the water? and if I aim at the engine I need to find a bit that represents the water jacket without getting too close to the exhaust/inlet  manifold or fuel lines etc etc . Will maybe do some experiments next engine run.

 

................Dave

Link to comment
Share on other sites

52 minutes ago, dmr said:

That's a scientific experiment, not a real world measurement ?

 

I.R. thermometers measure infra red emission, not temperature. Do I point the thing at my green painted engine, a black rubber hose connection, or a copper pipe containing the water? and if I aim at the engine I need to find a bit that represents the water jacket without getting too close to the exhaust/inlet  manifold or fuel lines etc etc . Will maybe do some experiments next engine run.

 

................Dave

 

It doesn't  have to be completely accurate, just repeatable so that you get to know what temperatures at various points indicate "normal", and thus any significant deviations are "abnormal".  ?

Edited by cuthound
Missing quote mark
Link to comment
Share on other sites

3 hours ago, cuthound said:

The cheapo one from I have from ebay is within 1.5°C when pointed at a black pan containing boiling water.

 

3 minutes ago, Dr Bob said:

As does mine!

 

If they are reading 1.5°C they aren't working correctly.  My one from Lidl reads around 100°C when pointed at a black pan containing boiling water ...

 

This throws into doubt all that work done @Dr Bob did on ecofans - which could be 67 times better than we thought!

  • Haha 1
Link to comment
Share on other sites

2 hours ago, TheBiscuits said:

 

 

If they are reading 1.5°C they aren't working correctly.  My one from Lidl reads around 100°C when pointed at a black pan containing boiling water ...

 

This throws into doubt all that work done @Dr Bob did on ecofans - which could be 67 times better than we thought!

But 67 times nothing is in fact still nothing, so no change

  • Haha 2
  • Horror 1
Link to comment
Share on other sites

Engine water 80 degC    (from Thermocouple in head)

 

with cheapo infra red:

rubber hose from thermostat 64

copper pipe (after rubber hose) 64   (surprised these two are the same and so low)

water pump 70

cylinder head (inlet side) 70

cylinder head (exhaust side) 78

 

water pump and cylinder head painted dark green

 

...............Dave

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.