New theory re overheating - poll needed?

[hatman]

The various reasons for Elan overheating problems are well understood and have been well aired (unlike some radiators):- missing foam radiator/bonnet seal; blocked vent grille to nearside (in UK) wheelarch; radiator too small; radiator too far back; electric fan wired up to suck instead of blow; electric fan not working; need to use a water 'wetter' (any more? - I can't think of any offhand.) What I can say is that my car has never shown any tendency to overheat, even in summer day stop-start traffic conditions and it has always had only the bog-standard engine cooling arrangements.

It was while idly glancing at RichC's avatar that the penny dropped. Could it be your car's registration number that's causing the problem? My own car's registration comprises only five characters rather than the more commonplace seven (ABC 123D etc) and as our front numbers are pinned on to the already minimally-sized front air intake the blanking effect of all those letters and numbers must be significant, especially so in the aforementioned hot, stop-start driving conditions. Well, what do you think? Ever overheated and if so, how many characters have you got pinned to your front end?

[1964 S1]

Another poll is an excellent idea! Heck, it'd be fun to poll all the questions. The baby Elan poll is a terrific concept.

I live in the states, have no letters on my +2 intake grille and that car has overheated twice. My S1 has no letters on the intake grille and has never overheated.

Eric

[RichC]

Hi Hatman,
your hypothesis sounds plausible !
Just needs someone to test it by driving their car with reg numbers removed to see if it makes a difference..
i'd offer but it will be a while before She's back on the road.
RichC

[John Larkin]

I have just two plastic characters in my front number plate and I had serious overheating problems in slow urban traffic until I installed an electric fan and an electric water pump. I have had no overheating problems since, even when on the Continent in summer. I not sure that the plastic digits are high on the list of suspects.

John Larkin.

[rocket]

7 letters on my grill and touch wood never a problem with overheating..sorry hatman...


Ian.

[Elanintheforest]

My S3 has 7 digits on grille, no electric fan, no overheating problems in 30 plus years, city traffic or thrashing up the motorway for hours. Wide Triumph radiator with single Anglia fan blade on water pump.

And on the subject, a couple of years ago, I had a chat with Tony Thompson (TTR) regarding a posh ally radiator for my Plus 2, which has the 170bhp BDA engine. Before I'd finished the sentence he cut in...."with that sort of power in a BDA, you will absolutely need the best 26r style rad with swirlpot...the engine wouldn't last 10 minuites with a standard radiator".

The car has has the standard wide Triumph radiator fitted for all of the 37 years and 80,000 miles that the BDA has been fitted....and the car used to live in London traffic, and regularly be used for touring Spain and Italy in the summer months. It also has 7 digits, and won't be having any fancy rads fitted.

I'm absolutely certain that if you don't live in a hot climate like Southern Europe, California or Australia, and you have an overheating problem, there's someting wrong with the car, not the original design.
Mark

[hatman]

Ah well, another bright idea sunk without trace. Still, never mind, I'm working on another theory at the moment that the difficult hot-starting problems may be somehow linked to the type of badges on the car...

[John Larkin]

Ah well, another bright idea sunk without trace. Still, never mind, I'm working on another theory at the moment that the difficult hot-starting problems may be somehow linked to the type of badges on the car...

Would that be described as forward or lateral thinking? I suppose it depends on whether you are discussing front or side badges.

John Larkin.

[GrUmPyBoDgEr]

If the engine starts to get hot actuate the headlamps a few times.
This will temporarily increase the air flow into the area in front of the radiator.
The exhausted air from the vacuum units will also help in one direction.
An additional lip seal around the headlamp pods will also reduce air leakage losses.
Removing any excess retaining stud thread from the lotus badge will clean up air flow with a secondary benefit of considerable weight reduction.
Pushing 29?C in the shade here; I must get out of the Sun!

Cheers
John

[rgh0]

Mark
I think Tony's advice while good, is conservative. My competition Elan with more power than your BDA has run with the standard radiator OK for many years more than 10 minutes in a much hotter climate and with much heavier usage than road use. Ran with standard 2 row radiator for a lot of years until it needed recoring and went to 3 row narrow radiator as cost was same and ran that for a lot more years.

Recently went to 3 row wide triumph radiator and not much difference which I think is mainly due to most of the flow going down the left hand side and the full width not being effectively used in the 3 row core design - I suspect a wide radiator may be actually better in a 2 row design than 3 row.

I suspect Triumph and Lotus went to the narrower radiator for the same reason as they discovered it did just as good a job as the wide one and was cheaper.

For all normal usages in most of the world including most civilised hot climates ( I rule out the middle of the Australian deserts) the standard radiator that was fitted should be fine if the total system is in good condition - regardless of the number of digits on the grill i think - especially with a modern ducted fan.

Just fitted 2x 9 inch fans to my wide core radiator to see if that makes it better at the end of a race when slowing down and loosing the forced air flow on 40c plus day and with all the heat soak from a hard worked engine which is really the only time the car starts to get hot. In normal road use never an issue as cant really use all that power for to long without loosing my licence

cheers
Rohan

[GrUmPyBoDgEr]

Mark
I think Tony's advice while good, is conservative. My competition Elan with more power than your BDA has run with the standard radiator OK for many years more than 10 minutes in a much hotter climate and with much heavier usage than road use. Ran with standard 2 row radiator for a lot of years until it needed recoring and went to 3 row narrow radiator as cost was same and ran that for a lot more years.

Recently went to 3 row wide triumph radiator and not much difference which I think is mainly due to most of the flow going down the left hand side and the full width not being effectively used in the 3 row core design - I suspect a wide radiator may be actually better in a 2 row design than 3 row.

I suspect Triumph and Lotus went to the narrower radiator for the same reason as they discovered it did just as good a job as the wide one and was cheaper.

For all normal usages in most of the world including most civilised hot climates ( I rule out the middle of the Australian deserts) the standard radiator that was fitted should be fine if the total system is in good condition - regardless of the number of digits on the grill i think - especially with a modern ducted fan.

Just fitted 2x 9 inch fans to my wide core radiator to see if that makes it better at the end of a race when slowing down and loosing the forced air flow on 40c plus day and with all the heat soak from a hard worked engine which is really the only time the car starts to get hot. In normal road use never an issue as cant really use all that power for to long without loosing my licence

cheers
Rohan

Hi Rohan,

I think your theory on wide & narrow radiators is on the mark; with the coolant flow choosing to go down the path of least resistance, leaving the furthest rows with less coolant flow.
That's talking about the original "Top to Bottom flow" radiators.
Cost was most definitely a consideration & the narrower version would have had fewer number of tubes because of that.
When going to 3 or 4 rows, the effectiveness of the rear rows becomes compromised, being partially obstructed by the rows in front of them, regardless of staggering.
The cooling air reaching those tubes will also have become heated by the front rows.
With modern cross flow radiators the manufacturers choice is a wide radiator on order to reduce the number of cooling tubes & of course to fit in the available space.
The coolant also has less choice of where it has to flow within the radiator.
Due to the limited space & high output of modern engines 4 row radiators are practically "standard".
To assist with the airflow through them the tubes are "ovalised" almost to the extent of being flattened in some cases.

One thing that seems to have been overlooked when regarding radiator efficiency is the clogging of the cooling fins by insects & other debris which can build up considerably depending on use.

A worthwhile tip is to give the radiator a blast of compressed air from the back of it occasionally.

Cheers
John

[JJDraper]

Another theory for you all.. Is there any evidence that Elans blow head gaskets more than +2s? My theory is that the heater arrangement in a +2 ensures that there is always flow through the block as the heat output is controlled via flaps in the heater box with full flow through the heater matrix at all times. Whereas from cold, the Elan has a compromised flow with the heater off, a valve shuts off flow to heater matrix. In hot weather, there is a chance that the engine will be heat stressed due to hot spots until the thermostat fully opens. May all be a load of ***p, but I think about these things....

Jeremy

[bcmc33]

I?ve said this many times on the forum ? the main problem with the Elan cooling is the basic design flaw of having the filler half way up the system. Even when successful in getting the heater system full of water, the top hose will always be empty. The best and cheapest remedy is to blank-off the radiator filler and fit a thermostat filler housing which will be at the top of the cooling system. You can use the low cost standard Ford item or the very nice Cliveyboy part specifically designed for the Elans.

I well remember my old S2 days in the late 60?s when the best way I found to reduce water temperature on a hot day was by putting the heater fan on full-blast. I fitted a Kenlowe rad fan but the heater fan remained the best method.

[GrUmPyBoDgEr]

Jeremy,

I'm not certain about the flow diagram in the +2 but I have also been told that the heater matrix always has a flow of coolant through it as opposed to the (Baby ) Elan
In both cases however the thermostat is positioned within the sytem to do it's job properly.
Assuming that it's an 80?C thermostat then that is the point at which it begins to open & permit coolant from the radiator to enter the system. As soon as the coolant around the thermostat sinks below 80?C it will close again.
Cooler water from the radiator passes through the engine & absorbs heat until it reaches the thermostat once more. This effectively causes the "thermoshock" effect you mentioned but would not introduce air into the saystem
How far the thermostat opens or even if it fully opens is dependant on the the heat that the engine is producing & also on how effectively the radiator is working. During the warm up period the thermoshock effect is nothing to worry about.
If however a larger much more effective radiator was fitted, a much bigger temperature drop across the radiator should be anticipated, thus subjecting the engine to a higher number of minor thermoshocks during the whole operating range.

The "Bypass systems" use a different type of thermostat with 2 valves working in "Tandem" with the single wax element.
The cooling system is split into 1 smaller system (which includes the heater circuit) & the main system which includes the radiator.
During warm up when the thermostat is closed only the "Small" system operates. When operating temperature (80?C) is reached the larger valve slowly opens the main system while the smalet valve slowly closes the small system. This swings back & forth until the thermostat is fully open & the full flow of coolant flows through the radiator.
It is this that provides better mixing of hot & cold coolant within the engine & reduces undesirable temperature swings.

Brian,

I didn't know that the standard Elan radiator was not at the coolant systems highest point; which it should be as you point out.
If that really is the case then I would consider it as a serious design mistake
I mentioned in a previous post the generally accepted method of filling cooling systems.
It seems in the case of the Elan that the front of the car should then be raised until the filler neck becomes the highest point in the system.
As has been said, the extended thermostat housing with filler neck overcomes that problem.
I thought that these were incorporated into modified Elan cooling systems which utilise cross flow radiators, thus providing a cooling system "high" point & a filling point.
Perhaps "Clive Boy" also took the problem of the position of the production cooling system filler neck into account when he started making his shiny bit?


Just an observation.
All these postings on cooling systems gives me the impression that just after getting the Elans out of the Garage after the Winter break, the worries about the Summer & overheating start to reccur

Cheers
John

[bcmc33]

Johm,

Most cars in the 50?s and 60?s had this well know design flaw ? and probably well into the 70?s, as well. You have to keep in mind that designs changed very slowly in those days, and it was at the time when a heater was, at best, an optional extra for most cars. I can?t remember when it became common practice to have the water reservoir at the highest point under the bonnet (hood).

I can only comment about my Sprint where the top of the water system is the inlet and outlet hoses of the heater. The thermostat filler housing is still only marginally the highest point of the system, but sufficient to complete a full fill.

I was discussing this subject with an ?old? friend yesterday and was reminded of one trick that the local Lotus Cortina boys did in the 60?s. It involved fitting a modified Schrader type valve (to suck not blow) into the top hose and using a bicycle pump to draw out the air and lift water from the top of the rad header. With someone keeping the rad topped-up it was possible to have a full system. Ingenuity at it?s best.

I?m sure there is someone in the forum that knows when Ford first introduced the thermostat housing filler.