The Triumph Dolomite Club - Discussion Forum

Woh - but you cold have heated 24 towels for 5 seconds over 2 minutes, more heat would have transferred from the rad to the towels beacuse they were cooler. If the flow of water to the rad was fast enough it would stay warm, too slow and the rad would have cooled.

If you know you are right then the laws of physics must be wrong.

If you can make a living fitting new central heating pumps when all that was required was balancing the system or clearing an air lock best of luck to you. Do you do those power flushes as well?

Mark.

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Mark.

Trying to compare a Central Heating System to a Car cooling system to me is wrong,
One is trying to keep heat in the other is trying to lose heat.

You pay's your money and take your choice.

As for if it goe's wrong same problem with a standard pump.

Keep a eye on the temp gauge as in a noraml car.

Luckly enought I have a digital temp gauge that will sound if the temp goes over a set temp.

_________________
2009 Mini Clubman Cooper S Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Back in my possession 22 September 2019.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020
212Hrs @31/12/2021
352 @ 28/11/2022
455Hrs @ 20/10/2023
480Hrs @ 14/03/2024
This is time taken at the Sprint not necessary time worked.

Working on a ratio of just 7Hrs a day not including driving to the Sprint.
That equals to 68 days that doesn’t include weekends.
Member TDC no 0471

Project 13B Sprint now back on.

No, they are both closed circuit cooling systems designed to release heat in a controlled manner. The only difference is with a car you ultimately control the boiler (engine) temp by controlling the heat lost by the rad, whereas a central heating system you control the rad output (room temp) by limiting the input to the system.
The operating principle is exactly the same.

FWIW Im with Dollyboy on the use of EWPs. Coolant flow is 'sufficient' with either mechanical pump. Bigger rad to provide more cooling is the ultimate answer.
The equivalent of putting wet towells instead of dry ones on your rad.

Mark.

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Mark.

?????

I really dont want to be tarred with the argumentative brush, but they're actually doing exactly the same job, i.e. trying to lose heat into air.

a boiler burns fuel (whatever type it is), gets hot, heat is transferred to space via water running through radiators in a closed circuit, forced by a circ pump. the cooler water returns to the boiler and is reheated, process is contiuous until the thermostat or timer turns the boiler off. the circ pump generally runs continuously until the heat from the boiler is purged before switching off.

if you dont disperse the heat at the correct rate then something doesnt work, the boiler switches off as it overheats, or if the water moves too quickly it doesnt stay in the heat exchanger in the boiler long enough to absorb the heat to send to the radiators, so the radiators never get warm. its a bit hard to achieve the latter in a household system due to the amount of heat a domestic boiler can produce.

a car engine burns fuel to produce motion, the net result is typically 4-7KW of waste heat that needs to be dispersed, via coolant running through a radiator, forced by a circ pump. the only difference is the rad in a car is a heat exchanger with a big fan, rather than a naturally convecting white metal box filled with water with fins on the back, screwed to your walls.

the biggest difference is a household water heater/boiler churns out 20-30KW, a boat heater can be anything from 2-10KW, so a boat heating system is closer to the heat output of an engine, and those jabsco pumps are fitted to literally hundreds if not thousands of boats.

jabsco pump will do the job just fine, better to just wire it to come on when the ignition is live and run the system continuously with a stat. water coming out the rad will be less than 80 degrees, so the pump goes in the pipe out the bottom of the rad, just like the standard one, but I still reckon on a standard dolly lump to be used on the road, an ewp is a pointless investment. race car or big wopping great engine is obvioulsy a slightly different story. the money would be FAR better spent going towards getting an ally rad made by radtec or the likes of, with extra rows, more fins and a hardcore fan.

if we start talking about fan AIRFLOW rate and how that affects how well the radiator works, thats a different story altogether. in that case, the more AIR flow, the better the rate of heat dispersal.

must........ get......... a............ life..............

heeeeeeeeeellllllpppppp meeeeeeeeeeee.

Totally agree Dollyboy (apart from the flow bit )

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Mark.

Yer I think Kev is right about the flow rate. It obviosuly takes some amount of time to transfer heat from engine to the water, then from the water to the radiator/air.

So if the coolant and engine are in contact with each other for a small amount of time (high flow rate) then not that much heat will transfer from engine to coolant, and then not that much heat will be lost from the engine...

But... if the engine and water are in contact with each other for a slightly longer amount of time then more heat will be transferred from the engine to the coolant, therefore the right flow of coolant is far better than a very high flow of coolant

Just for the fun of stirring:

But if the water is moving faster it moves past the hot stuff faster too and so contains less heat energy. So yes, it dissipates less heat per pass of the rad but it picks up less energy per cycle through the engine. It also makes more passes per unit time so shifts the same energy overall

Where's the great big wooden spoon smilie

Tinweevil

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1978 Pageant Sprint - the rustomite, 1972 Spitfire IV - sprintfire project, 1968 Valencia GT6 II - little Blue, 1980 Vermillion 1500HL - resting. 1974 Sienna 1500TC, Mrs Weevils big brown.

That's well and good

BUT

Temperature loss follows an exponential decay curve as it tends towards the ambient, as does temperature gain. Water has a fairly high specific heat capacity, so whether pumping the water twice as fast is useful or not is really fairly complicated.

Just to stir things up let me add my views from daily actual experience.

Flow rate,

Had more than one occasion with engines overheating. Running fine at low to mid range but got too hot at higher speed. They were fitted with central heating circ pump. Solution- fit engine driven fixed displacment pump. Higher speed = more energy= more heat. This required more flow to remove heat from engine block.

Flow WILL vary with pipe bore. As I recall from studing fluid dynamics in physics, small bore = higher velocity and pressure but low volume( flow rate ). Large bore = lower velocity and pressure but higher volume.

I don't know for sure but I suspect the control unit on Davies Craig controls actual flow rate rather than just switching it on and off. Even in today's market of robbing b*st*rds I can't see them chargin 150 quid for a thermoswitch and relay!

This exciting NEW concept offers more available engine power, better mpg, improved cooling with quicker warm up and longer engine life.
It is supplied in kit form to replace existing belt driven water pumps.
Use with an adjustable electronic controller which supplies exact voltage to govern water pump speed to achieve desired cooling requirements.
Owners of older cars with troublesome original pumps have also achieved new found cooling reliability.
The existing belt driven pump is inefficient in that to allow sufficient circulation at low speed, the flow generated at medium to high speeds is not required and is wasteful of engine power as is the energy required to speed up a mass of water through a restrictive radiator during hard acceleration. Water circulation ceases on turn off and engines are often "cooked" by switching off after a high speed run.
The water pump may be fitted in any location where it can be connected into the bottom hose, adapters are supplied to suit various hose diameters.
It is not necessary to completely remove the existing water pump. The pump pulley can be disconnected and a shorter belt used, the pump will then idle and offer no resistance to flow. Alternatively the old impeller may be removed from the shaft.
EWPC1 Electric water pump controller
£82.40 (Excluding: VAT at 17.5%)

_________________
2009 Mini Clubman Cooper S Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Back in my possession 22 September 2019.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020
212Hrs @31/12/2021
352 @ 28/11/2022
455Hrs @ 20/10/2023
480Hrs @ 14/03/2024
This is time taken at the Sprint not necessary time worked.

Working on a ratio of just 7Hrs a day not including driving to the Sprint.
That equals to 68 days that doesn’t include weekends.
Member TDC no 0471

Project 13B Sprint now back on.

Higher speed = more energy= more heat.
Rad unable to lose enough heat=overheating.
The rad only drops around 5 degC from inlet to outlet, unfortunately this is not good enough if the engine increases coolant temp by 5.5 degC from inlet to outlet.
Higher flow rate would reduce these figures, doubling flow would result in the rad shedding perhaps 3 degC. but only picking up 3 degC in the engine.
Extra cooling would come from the fact that the return side of the rad would be 2 degC hotter, so dissipate more heat overall. Marginal difference perhaps, but still a slight improvement.

Standard rad offers too little surface area and/or too much resistance to air flow to provide enough cooling. Answer is a bigger (or better) rad. Obviate the need for a bigger pump.

Fan is irrelevant at speeds above 30mph. Far better to remove the wasteful power sapping mechanical fan (which results in additional unnecessary heat being produced by the engine). Fit a decent shrouded electric fan behind the rad to provide decent air flow when you need to shed some heat after slowing down.

Fixed displacement pump? Do you mean a positive displacement pump? These produce small flows with high pressure. (Oil pumps). I've only ever come across radial centrifugal pumps in cooling systems.

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Mark.

I've had a DC EWP fitted to my track Sprint for about a year now. I must admit that I'm not convinced that it's cooling any better than the standard pump although there is a mod I can still do to lower the temp. range of the pump. I suppose it does take a load off the jackshaft which must be a good thing? also, after coming off the track, I can turn the engine off & still have the coolant flowing.

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Sprintless for the first time in 35+ years. ... Still Sprintless.

Engines, Gearboxes, Overdrives etc. rebuilt. PM me.


1997 TVR Chimaera 450

That's my way of thinking.

_________________
2009 Mini Clubman Cooper S Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Back in my possession 22 September 2019.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020
212Hrs @31/12/2021
352 @ 28/11/2022
455Hrs @ 20/10/2023
480Hrs @ 14/03/2024
This is time taken at the Sprint not necessary time worked.

Working on a ratio of just 7Hrs a day not including driving to the Sprint.
That equals to 68 days that doesn’t include weekends.
Member TDC no 0471

Project 13B Sprint now back on.

but as you know when you turn the engine off the temp rises in the cooling system (heat soak) but it's really down to choice but i'd rather it got warm (not too warm) not be overcooled

_________________
2009 Mini Clubman Cooper S Daily Driver.
1980 Dolomite Sprint with a touch of BLTS
Balanced Lightened and Tweaked 13B Rotary and SuperCharged.
Back in my possession 22 September 2019.
Rebuilding the Sprint time taken so far, 111Hrs@15/12/2020
212Hrs @31/12/2021
352 @ 28/11/2022
455Hrs @ 20/10/2023
480Hrs @ 14/03/2024
This is time taken at the Sprint not necessary time worked.

Working on a ratio of just 7Hrs a day not including driving to the Sprint.
That equals to 68 days that doesn’t include weekends.
Member TDC no 0471

Project 13B Sprint now back on.