The Plastic T-Piece

[T-Cut]

Originally Posted by kaiser

If the extra water is not cooled actively, it will not increase the cooling by much, simply just a bit more cooling owing to larger surfaces. If you want to increase cooling a larger radiator is required, or a longer time in the radiator or a bigger temperature over the radiator.

I think the extra volume would have quite a dramatic effect. Increasing the coolant content by say 15% would reduce the 'average' temperature by a similar amount simply due to its greater heat capacity. The heat produced by the engine is basically absorbed by the coolant and the engine mass. That heat is transferred to the surrounding air via radiation and by conduction through the radiator. When the running engine is in thermal equilibrium, the heat generated is equal to the heat lost. The overall temperature remains static because the heat contained within the engine mass and the coolant remains static. The equilibrium temperature of the coolant is controlled by its overall mass. Since the heat generated is more or less fixed, using it to warm up a greater mass of coolant will reduce the equilibrium temperature. It's basic physics really. So, a 15% increase in coolant volume (mass) will have a 15% reduction on its equilibrium temperature. I'm assuming the coolant is primarily water with a specific heat of 1.0 cal/g. The actual SH of 50% coolant mix will be slightly different, but not enough to alter the basic result.

TC

[T-Cut]

Originally Posted by stevemac

If the pump has a fixed capacity does more volume mean it would travel slower through the rad.

No, it has no effect at all. The time taken for all the coolant to cycle through the radiator will increase, but the flow rate remains the same. The radiator will have less work to do in fact, because the coolant going in will be at a lower temperature due to the thermal changes described above. The heat exchange rate will go down slightly because the coolant and the air have a smaller delta T.

All this will be academic of course, if there's no room to fit the wider bore hoses.

TC

[kaiser]

I could go technical on you here, but you are of course right, you have 15% more to cool with. Initially.
Once all water has been through the system, and brought up to working temperature, you have largely lost this advantage, because you just have a bit more water, but still at the operating temperature of the system. That is why you actively need to cool more to get the advantage of more water.
You can believe me on this. The extra liter of water (say 15%) you are talking about will not give you an extra 15% cooling, it will run through the radiator at the same speed and see the same cooling there, all controlled by the thermostat. Most of it, in your case, will be stored in a larger pipe. The cooling here is insignificant, unless you increase the surface of the pipe dramatically.
You are only achieving a larger mass of water which will give you a buffer, which will obviously be an advantage, but not the way you imagine.
Sorry for this.

[dustybin]

The higher the rpm the faster the pump spins which increases flow,the pump does not have a fixed flow rate, theres nothing wrong with the cooling system,,it´s the engine thats at fault,,we need a better engine with more coolant capacity,not somthing that was increased from it´s origanal 1.1 or whatever it was. vw and audi have full alloy engines and they dont have this problem, build a car on a shoestring and this is what you end up with..

[Time Searcher]

I am following this thread with great interest... I did a bit of research on this subject just after buying a new ZTT 120 and being concerned about the dreaded HGF, I found the following information at < http://web.tiscali.it/elise_s1/ >. Whilst it isn't directly applicable for the engine installation we are discussing on this thread, it does show some background information on engine temperatures and some thoughts on coolant flow etc. Worth a look anyway...
Regards,
Martin

[kaiser]

Dustybin there are good reasons for doubting the cooling system. Page through the problems on these pages and you will see.
There are certain weak spots which will cause water loss, rapid and unnoticed.
An engine does normally not just develop HGF, it is usually preceeded by an overheat situation. In normal cars it is a rare occurence and often caused by a stuck thermostat. In the Rover it is often caused by an un-noticed loss of water. The main reason why we have this predicament is the temperature gauge (which gives no warning of impending doom) and a lack of a water sensor. I know VW, BMW and maybe even AUDI uses water level sensors, and why Rover did not is a mystery.
The Rover engine itself is fine if you can keep it cool, I actually think the 1.8 is absolutely amazing, but we might disagree on that point, it is to a large degree a matter of preference.

[dustybin]

I know there is weak spots, and plastic is always a problem,but they should of rebuilt the bottom end, made it bigger and added more water around the cylinders,they saw a tax advantage with the 1.8 and took a chance,,time has proved them wrong,and landrover were stupid not to use the ford engine but to go with rover..will be interesting to what the chineese have done to inprove it or not,if it´s the same god help them...but if rover could not sell them what makes them think the british will rush out and buy a design that is now getting old...

[kaiser]

Originally Posted by Time Searcher

I am following this thread with great interest... I did a bit of research on this subject just after buying a new ZTT 120 and being concerned about the dreaded HGF, I found the following information at < http://web.tiscali.it/elise_s1/ >. Whilst it isn't directly applicable for the engine installation we are discussing on this thread, it does show some background information on engine temperatures and some thoughts on coolant flow etc. Worth a look anyway...
Regards,
Martin

I have had a look at the link. It is indeed interesting. Well worth the read!
I am at the moment busy manufacturing a new thermostat housing for my V6. And to make it durable I am carving it out of Swiss Cheese.
I am copying the original design though, and it has exactly the type of pressure relief valve described last.
However I don't think one has to make life too complicated, and I suspect that although initially the 1.8 engine had a weakness with the headgasket, to some extent, I sincerely believe that overheating causes HGF in these engines. After the HGF has developed, it is difficult to see if water was lost before or during HGF . The owner is not exactly going to jump up and down insisting that he did notice any leak before the event, if there is a warranty claim, is he? Provided he had checked the water level in the last 5 months.
The fact is we are getting used to normal cars where you don't have to add water ever! We drive the thing and expect our instruments to warn us if something is amiss!, And why not, that is what they are there for! Well, not in the Rover. And you just need to be aware of that, and act accordingly. Check every day!
My advice is simple, keep it cool and keep it alive.

[T-Cut]

Originally Posted by kaiser

You are only achieving a larger mass of water which will give you a buffer, which will obviously be an advantage, but not the way you imagine.

Yes, I've already seen the fallacy. The extra water simply increases the time to get to equilibrium. Once that's stablished, the water temperature remains as it was. Still, more coolant volume would make it a little more tolerant, but not much.

Sorry lads, back to the drawing board!

TC

[Gman2]

I've followed this thread with great interest - as most likely all 1.8 owners. It was recognised that the introduction of the PRT from late 03 onwards was a great improvement on the cooling system. Therefore is it a better option for owners to retrofit the PRT. Not sure how feasable that is, costs etc but could be less problematic than adapting hose bores etc?