Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) placement of the "Union Jack" on Bonnet sides

Not sure you are aware Dave but there have been several reports of the 4 cylinder cars running hotter under certain motorway (I believe) conditions after fitting larger after market ally rads.

Thoughts were that the extra cooling available mucks up the cooling hysteresis with thermostat staying closed longer hence higher temps for a while. Solutions ranged from fitting lower temp stat (probably reason for yours) to masking off part of rad intake, although latter seems counter intuitive to me.

FWIW fitting such rad made no difference on my 3.7 V6 Roadster suggesting better match to increased cooling available. Only difference was that fan rarely comes on now.

Monty ....Not as much as should ... my guess would be high pressure build up in the engine bay not allowing the rad to flow freely ... my car runs fine without overheating ... but if it did, my first try would be a short ali floor fixed between the chassis rails to about a third of the engine bay with a 1/2" angled kick down on the back edge to create a low pressure area behind the rad ... then let the underbonnet air bleed out through the louvres and under the car (my car has plenty of ground clearance and the crossflow sump doesn't project below the chassis rails)... as you say, without hard Morgan related data (which probably isn't there) we're shooting blind but I'd try that before anything more expensive.

K

Ps ... I wonder if the GT and LeMans cars saw a wind-tunnel? ... not Trads but would be interesting to see.

All I can add is that my 3L Roadster had the air conditioning radiator slightly slanted underslung between the chassis rails and did not require the (switched) fans on whilst moving, there was more than enough passage of air thru the radiator for the air conditioning radiator to work without the assistance of fans. Only when in very slow moving or stationary traffic did I need to switch the air conditioning radiator fans on.

I also had a Sifab ali radiator fitted with standard thermostat ,and the airflow thru that may have been affected by the lower slung air conditioning radiator, the ali rad. ran only slightly cooler than the original radiator, with the fan only coming on in slow moving or stationary traffic for both the original and ali. radiators. Which was reassuring as I had read that the ali rads were much more efficient and do run the engine much cooler than the engine was designed to operate at

There may be a split here between the older/newer trads .... like many here, I grew up on pre-70s cars (and have a '70s Mog) .... with memories of overheating (slogging up long twisty hills with passengers and luggage watching the inexorable rise of the temperature needle) ... I like to have a free-flowing rad with the more air the better .... later cars may well be much more properly specced and installed in the cooling department.


K

i think there was a big step up in ICE cooling technology when manufacturers relocated the thermostat to the bottom rad hose with the top coolant rail feeding directly via top hose to rad unobstructed. The temperature sensing side of stat faces the rad and when partially or fully open feeds main coolant flow into a mixing chamber which also accepts bleeds from bypass and heater return, with its output feeding adjacent water circulating pump inlet. This configuration seems to allow better response to large changes in engine power demands, especially if stat is ECU controlled.

Just to be clear, I have extremely consistent coolant temps at 82c which is not an issue at all, however, strictly speaking the Duratec is designed to run a lot hotter at around 105-110c, and with the aid of an ECU controlled electric thermostat. For the record I'm logging true coolant temps at the head using my EMU Black standalone ECU, I am most certainly not relying on the readings displayed on the comedy instrument in the dash. I've proved this effort from Caerbont Instruments (the old Smiths factory) under reads by 10c or more depending on hysterias and mood, actually during the warm up phase it can be as much as 30c off as its rediculously slow to respond!

Morgan did use the Ford/Visteon ECU which has the capacity to control the electric thermostat, however, for whatever reason they chose not to implement this feature preferring instead to use an old school mechanical thermostat. Caterham who has also extensively used the Duratec engine over many years use a mechanical thermostat too, this may be because they use an ECU from MBE and it's not capable of controlling Ford's electronic thermostat, but I suspect its more than that.

Whatever the reason, it does seem everyone fitting a Duratec in a rear-wheel-drive application bins off the electronic thermostat, preferring instead to go mechanical with all the people converting Mk1/2 Escorts to Duratec, Frontline Developments, and I suspect every kit car maker out there do the same. Now, if you read the Caterham, Escort and Locost forums you to tend to see a clear theme in the posts around over cooling, which I believe is partly because the whole cooling system in a Duratec was designed from the outset via an electronic thermostat in mind, and partly because when everyone fits a mechanical a mechanical thermostat they fit an 82c one so perhaps that’s the only value available?

I do also have a breakdown somewhere from Rog on how the Duratec cooling system was designed to work in the OEM application, and all I’ll say is it’s a bit unconventional, undoubtably this is Ford finding new weird and wonderful new ways to accelerate the warmup phase and get their engines to run cleanly at Lambda 1 as soon as possible. These excessively complex additions such as electronic thermostats, electric water pumps and odd ball cooling system designs have all appereared in an attempt to come out of cold start enrichment just a few seconds quicker in order to meet ever stricter emissions standards.

At the end of the day running any engine at 82c is just fine, so I’ve elected to leave Monty like he is rather than push my coolant to 95c, only to potentially run into the real reason 82c is the go-to RWD stat value. Afterall, at even at just 82c Monty’s heater is fantastic and the engine is massively under it’s limit, saying that you can see Caerbont Instruments knew what temp the Duratec is meant to run at just by looking at the gauge scale.



image upload

You can clearly see the engine is meant to run at the mid point of the gauge, i.e 110c

I got stuck in some traffic for an hour on Sunday in the 3.7 and with alloy rad the fan came on for perhaps 2-3 mins and off for just under 7-8 mins, with the OE one it used to run almost continually under the same conditions, bear in mind that the part nr of an OE rad is the same for a 4/4...right through to a 3.7 beast

My louvres are "out" K, the same as on my old 4/4....! Did not count them......

Interesting that 3.7 V6 Ford Cyclone in my Roadster, ironically also part of the Duratec family, uses a plain mechanical thermostat as with other applications it was designed for, Mustang etc. as cutaway below.



On my car 98°C is held under all conditions with rare exception of rolling road dyno when it peaked 10 - 15°C higher.

Perfect temps Richard, and a nice old school mechanical thermostat controlling it

It seems that fortunately all this electric thermostat nonsense is limited to those burdened with front wheel drive.

And as far as I'm concerned they can keep them, it's just another thing to go wrong!


Shocking thread drift with this one mind, not sure how we got from badge positioning to electric thermostats