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MG MGF Technical - Cooling system Q and A..
| Hi all,|
I have just got confirmed that there IS a big diff. between the "F" and Elise cooling system outline !
The heater matrix on the Elise has NO valve, i.e. the heater system flows at full speed all the time and the amount of heat is regulated with flaps directing and mixing hot/cold air ! On the "F" the heater-valve (when shut) does block the vital bypass that the Elise has all the time... So if the "F"īs heater-valve is open all the time OR the thermostat is re-worked with bypass-holes the two systems will be more or less the same.
Any comments ?
Regards from sunny top down Sweden, Carl.
Just got the Elise diagram of the coolant system online on the 'coolant bleed page' of http://www.mgf-net.de.
Direkt link is
yes, saw your page but was not sure if they simply had omitted the heater valve so i asked the question on the "Elise BBS" how the heat is regulated.
IMO this is a significant change from the system we have on the "F" and can just be the diff. between HGF or not !
All the best, Carl.
|Interesting observation Carl/ Dieter. Might indeed explain the difference in experience of HGF between the two marques...|
|So how do we 'Elsify' the F's coolant/heater system without increasing warm up times? (apart from having the heater on all the time)|
|>>(apart from having the heater on all the time)<<|
Even this increases the warm-up time David, but your point is well made.
I don't think that increased warm-up time is a problem per-se. What is a problem is when the bypass hole leads to a failure of the engine to reach operating temperatures.
The correct compromise is out there- whether it is a case of a lower temp thermostat or a normal thermostat with a small single by-pass hole I am not sure yet. We need more experience with different set ups under different conditions!
|I am a bit slow,|
so having a heater on at full blast is good ??
does it have to be on full 'red'?
Donīt think that there is a need for "full red" in order to get some decent flow thru the system. Anyway it is only the flow of water that is of concern so the fan can be switched off...
Unlike You are on the South Island around Dunedin and slowly aproaching wintertime ! :))
Regards , Carl.
|I'd love to try the 82 degree 'stat but dealer insists he needs a part number....any help please ?|
|Go to a proper motor factor, AC DELCO are one of the OE manufactures ot thermostats who also provide the same for aftermarket sales. A factor will have a catalogue appertaining to OE fitment and different temperatures.|
got the same problem. In this silly stock times nobody can find parts without a part number.
Carl mentioned some the other year ?
Anyway, yestersday I added a drawing of my secong hand 88°C thermostat and hosted the measures on
Any part number of any car manufacturer is welcome :))
82°C in the right outer diameter ... where to get ?
|look up www.acdelco.com then thermostats. AC DELCO have agents world wide.|
and off now to http://www.acdelco.com
Joe, the best of the night :))
|>>>http://www.acdelco.com but nothing as useful as an application list by vehicle and temp or part # that could find (but it is late).|
|I just ordered an 82deg thermostat from my local autoparts supplier. According to his catalogues it should fit all Rover engines. I probably get it tomorrow, I'll post the details then.|
|Jon A. Fredheim|
|I noticed the other day that my local Halfords had stacks of thermostats... Which one would have been suitable I do not know- I am afraid I didn't look carefully enough... :o(|
|Sunny here, so Halfords gives me an excuse to drive the F (which I have pinched for the day). The 82 degree stat is from the 214 / 414 with the plastic housing, and Halfords' # is HTS605 and it costs Ģ6. I also note they do a replacement header tank cap - HRC606 at Ģ3.|
|Nice valuable thread... Was just impressed again of the hot air escaping from the engine bay when the boot is opened. Can't be healthy.|
Carl said: "Anyway it is only the flow of water that is of concern so the fan can be switched off..."
Does that mean that it is of no use to have the fanswitch on 1, while the temperature-switch is set on blue/cold. I thought the water started to ciculate as soon as the fan was started. Just a thought, but it xould help me to prevent you-know-what.
What do you guys think about mounting a fan (or couple of) above the engine, under the grill of the bootlid ?
Erik (thinking 'bout removing the heatshield preventing the alternator... which is cheaper than fitting a headgasket).
|>>Carl said: "Anyway it is only the flow of water that is of concern so the fan can be switched off..."|
Does that mean that it is of no use to have the fanswitch on 1, while the temperature-switch is set on blue/cold.<<
Yes, that's right- the heater water flow is controlled by the heater temperature valve. Therefore with the fan running and the temp on cold, there is no water flow into the heater matrix.
>>What do you guys think about mounting a fan (or couple of) above the engine, under the grill of the bootlid ?<<
Not sure that this would work as we know that the engine bay is already highly pressurised on the move- in fact fans could *restrict* the flow of cooling air. No, I think that the best, and simplist solution is to have larger engine bay vents...
>> (thinking 'bout removing the heatshield preventing the alternator... which is cheaper than fitting a headgasket). <<
An interesting thought - same had crossed my mind when reading Carl's heat data. I reckon one could do this, but one would also need to insulate the manifold with manifold tape to prevent melting the alternator- as JT warned...
|I wonder if delivering some cold air to the area of the alternator (with some K&N style piping) might work?|
|It's a slightly ackward area in which to project air, but it is an interesting idea Neil. Carl- fancy testing this out with your IR temp probe?|
currently I have fitted a small "soft" heatshield fairly close to the alternator but not so it disturbes the inbuilt fan flow of the thing .Hard to describe but consists of the same alu-coloured material usually found on Mumīs ironing-table !! A bit like what Demon Tweeks sells at a price... No adverse effects so far and no sign of any overheating.
I am not sure if I was clear enough in my writing about temp measurements but the main issue is IMO that we have all the air needed comming in IF IT ONLY HAD A CHANCE TO ESCAPE OUT ! As earlier said - the enginecomp. lid raises at the back at low speed and stays up with hughe amount of hot air passing thru.
Whatīs needed for more exchange of air is another (or more) air-outlets ! Anyone got any ideas of a neat soloution that blends nicely with the existing and doesnīt destroy the lines of the car ?
Something for Mike to consider ?
Regards , carl.
|hmmm... was thinking 'bout the Cup-cars... They are sucking air into the engine at the grill/vents where we want to get the air escaping.|
Another thing is that, if I remember well, the vents at the top of the lid aren't located above the vents at the underside of the lid. So there must be a way to get the air better in the lid andout of the spacein the lid.
Hope this all makes some sense, not really easy to get it explained.
>> would also need to insulate the manifold with manifold tape to prevent melting the alternator <<
...causing a raise of the temperature in the engine, right?
|>> would also need to insulate the manifold with manifold tape to prevent melting the alternator <<|
...causing a raise of the temperature in the engine, right?
I don't think so Erik- most of the heat is carried in the exhaust gases and not radiated by the manifold.
As an aside- hasn't anyone else seen the air scoop for the Lotus 340R? It is an F1- style ram air duct for the air filter. Nice, but very expensive! ;o)
|Tridon part # 8620 7882 is an 82deg thermostat commonly fitted to a lot of Rovers. It has a slightly larger diameter than the one fitted to the MFG engine.|
I got mine yesterday. Ground off the excessive diameter, drilled a 2mm hole in it and put it in. It works OK, can't notice any difference from the OE item. The thermometer stays one notch below half scale just like it used to with the 88deg 'stat fitted (before i drilled the two 4mm holes in it).
Anybody knowing what temperatures the scale of thermometer shows? Working temp around half scale is something eighties, of course. But what temp is redline? And at what temp does the scale start?
|I think it is an arbitory resistance scale Jon- no idea what the extremes of temperature signify on the scale or indeed whether it is linear. Shouldn't be too difficult to figure out though.|
Glad to hear that the 2 mm hole enables the engine to reach operating temperature. I presume it marginally slows the engine warm up period? If not significantly different, it may not be allowing sufficient bypass flow.
What is needed is someway of monitoring the temperature fluxes in the engine to confirm that the single 2 mm bypass hole is sufficient for the job.
Anyone got any suggestions?
Havenīt tried this yet but as the temp sensor for the instrument is for the instrument only and doesnīt involve any MEMS etc. it would be safe to arrange for a real precision thermometer with digital readout to be fitted in place of the original sensor. In a way the Elise have it this way - the sensor goes to the digital Stack unit. Following the threads on the Elise board they can quite easily see the variations in temps as our analouge instrument seems a bit "static". Just wonder if it is a moving coil or moving iron instrument. The moving iron (with damper) does need a lot of input to move the pointer around ! When I get the time and work permits I will probably do a test as per above...
Regards , Carl.
|You are quite right Carl- a number of folk on the Elise BBS have reported marked fluctuations of temperature.|
Do you think that the existing sensor would be a suitable measuring device if hooked up to a suitable digital multi-meter?
This might be a useful way of plotting engine temperature fluctuations- assuming that the water temp at this point in the cylinder head is representative of the whole engine...
I look forward to hearing about your discoveries Carl :o)
The manual gives the following figures for the coolant temperature gauge:
49 to 98ohms-65 to 85C-Approx. one third
24.6 to 32.1ohms-100 to 110C- Approx. halfway
16.9ohms-125C-Enters red sector.
A digital elise-type display sounds cool. I wonder if we will all be driven crazy by reporting every one degree change in temperature though!
|I can tell you that the indicated coolant temperature in the Elise is around 85-86 when cruising on empty B-roads, around 88-89 in traffic and, when really stuck in traffic jams, climbing slowly (in 5 or 6 minutes) towards 102-103, at which point the fan kicks in, lowering the temperature to 93.|
I'm sure that it must be like Carl says, i.e. that the F gauge must be dampened in some way, because I remember that the gauge in my former MGF VVC seemed to have only two positions: either stuck in the middle or shooting up towards the red.
|Just another thought: If you connect a digital temperature gauge to the blue sensor, make sure to change the latter first in order to avoid your fancy digital meter being fooled by your old and corroded sensor.|
|Carl mentioned a need to get air out of the engine compartments. I seem to remember seeing a Danish company offering an altered boot lid one year at Brooklands. He had dropped the outer skin so that it followed the bracing underneath in order to improve cooling without affecting boot space. Does anyone know what became of this idea or whether it worked?|
yes - it was even advertised in MG World (see No9 Feb/March-99). It seems to be a German company TAD Manufacturing, Advertise says "Contact Axel Klozenbuecher Tel: 01623 514779." It can be had in both steel and composite plastics (!)
If the one in plastics is lightweight it would be fine, but at the other hand not quite sure about the looks with the recession in the middle....
Dieter , do You know anything about this - anyone on the German BBS have one ?
My thoughts was in the direction of some moulded insert with good looks that doesnt spoil the lines but could be fitted after a cutout in the lid..
About taking a reading direct on a multimeter , - yes , one can at least see the changes and relate that to any moves on the dash instrument. Reading the volts across the sensor with a normal digital voltmeter would not load or dampen the sensor in any way as input resistance of the instrument is in the mega-Ohms.
Regards , Carl.
never heard about the mention guy. The 01623 514779 isn't a german number (IMO).
My be from Austria or Switzerland.
Any ideas ?
Yes, you're right it takes a little longer for the engine to reach working temperature with the 2mm hole in the thermostat. And I agree that it probably does not provide sufficient flow during the warming-up period.
Keeping the heater valve open until working temperature is achieved is IMO the only precaution that works for avoiding harmful thermal transients.
|I seem to remember that there was one of the "modified" bootlids at one of the Brooklands days - possibly the accessory day from a couple of years ago?|
I'm sure someone has a picture of it.... (in fact I can remember looking at one on the WEB)
|Despite Axel's name, TAD is(was?) a British based company. The boot lid had larger vents and the cover re-profiled to match the inner pressings.|
Unortunately, the boot lid has never seen the inside of a wind tunnel- and in fact, I suspect that it is considerable less aerdynamically efficient than the 'Kamm-tail' OE lid. The only positive thing going for it was the fact that it actually did have larger vents...
FWIW the boot lid's original design was intended to vent hot air through the apperature where we now mount HLBLs. Hot weather testing in Nevada put paid to that idea and the vents were instituted (there's something about this in the book, "Project Pheonix").
Perhaps this rather neat outlet could be re-instituted as a supplimentary hot air exit?
Hi Rob, have already checked the HLBL slot but unfortunatly they revised the steel pressings so no way out for the air at that place.
Still my thoughts are on a nice moulded part with bigger outlet that would fit after a cutout in the lid....
regards , Carl.
just to complete some ideas of air vent mods.
Here Rogers and Johns pictures of an air scoop under the car.
|Nice pix Dieter :o)|
Slightly off thread, but I checked Per's ECU temp sensor. To my surprise it is giving the same resistance range in hot water (circa 90 degrees) as the one I removed from my car- and within the reference range that was posted on this BBS.
Looks as though corroded electrical connections are to blame here...
Very interesting... Maybe one should just unplug and re-plug the connector repeatedly from time to time... Hmm...
|That's my thinking too Per.|
checking with an Ohm-meter is mostly OK - but remember that this device has very low voltage and current going thru the sensor when testing. In real life there is more current and hence the bad joints at the termistor or other places start to show up.. Somewhere in the specs. i read that every electrical connector is specially prepaired to withstand oxidation an other contact problems due to some treatement.... Now we see what thatīs worth!
Regards , Carl.
|Ah, I see what you are saying Carl. Good point. Any other way of testing the sensor then if the ohm meter is not adequate to detect a fault?|
This thread was discussed between 13/05/2001 and 21/05/2001
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