What's the best radiator solution

[alaric]

I know this has been discussed many times, but I would really appreciate a push in the right direction.

What's the latest on the best most cost effective solution for cooling that'll ensure the car does not overheat in traffic? So far I've gleaned that the full width triumph rad is the one to go for, but then I have the option of

The ally one from ebay at ?315
Tony Thomson setup for a road car with the rad at ?345, swirl pot at ?130, and fan kit at ?138. This is all pre vat.
Clive boy's thermostat housing with integral rad cap, with the full width rad or another more modern rad yet to be identified.
A full width rad from the likes of Paul Matty.
My own rad which is 3 core and I believe the standard one for my '72 +2 S 130/5, but which has a weeping leak that needs repairing and doesn't fit anyway since the bodywork was reworked.

I only want to spend the money once, and since overheating is so annoying and upsetting and can lead to damage, I really want a sure solution to this.

Thanks in advance.

[rgh0]

For a standard road car a three core standard narrow radiator with a modern electric fan should be plenty in any environment and in the UK overkill.

I have this in my Plus 2S 130/5 and it has no problems in 45C days in heavy traffic. Anything more is not needed if the rest of the engine and cooling system is in the right condition.

I ran the same cooling system in my competition S4 Elan with 180hp on hot 45 C race days and it was OK (just). Recently changed to a the full width 3 core S3 triumph style radiator and it has only been a marginal improvement as I think the water distribution in the wider radiator is not as good. The wider S3 radiator was the standard in the S4 for Austrailain delivery Elans, my S4 was a private import from the UK. Currently installing 2 fans to get better coverage of the wider radiator to see if it improves.

The other options I believe are very expensive for road cars such as special alloy radiators and their installation is often not a trivial amount of work compared to fitting the standard narrow or wide Lotus / Triumph radiators in 3 row core versions which should handle any road use any where in the world

Just my opinion - and lots of people fit a big modern alloy radiator for peace of mind and that is a legitimate approach

cheers
Rohan

[steveww]

If you go with a non standard rad the swirl pot is not required, just use cliveboy's thermostat housing. It also has the correct mounting for the fan switch.

I know other people say the standard narrow rad works for them but I never had any luck with it. I have fitted a full width rad down in the nose with a 10" electric fan. At speed not matter what the ambient temp the engine runs at 80C. Stuck in traffic with 36C ambient the fan cuts in at 95C and pulls the engine temp back down to 85C in a couple of mins. No more overheating worries

See http://www.steveww.org/index.php?id=26 I used a standard Ford thermostat housing as clive's was not available then. You can get Pacet fans from less expensive places than TTR.

[alaric]

Thanks for the replies so far chaps. I am quite keen on Cliveboys thermostat housing, but really don't know which third party radiator can be used. I could, for now, get Clive's housing and have the existing cap housing, on the rad, filled in and removed. But, that'd cost money which I could just throw at an Audi rad or some other modern car rad that I could fettle into place. If there's a web site that gives the dimensions of their rads then I guess I could measure up and choose one.

All the best.

Sean.

[terryp]

Sean
When I got my first plus 2, it didn't have the blanking card, the foam on the bonnet or a recuperation bottle and its number plate was 1/2 way over the nose.
Correcting those things made a startling difference in cooling.

Terry

[GrUmPyBoDgEr]

Hi Sean,

using something like Clive boys thermostat housing is a good start, providing "the highest point" in the cooling system which will help in filling the cooling system & eliminating air pockets.
The TTR "swirl pot" is not really a "swirl pot" being rectangular in shape with radiused corners. It's purpose in life is to provide that "highest point" in the top hose.
From there on you will have to do a juggling act with top & bottom hoses depending on your final choice of radiator.
If it's a modern one it will be aluminiun cross flow with plastic end tanks.
I for example used a BMW part in my Zetec Elan (positioned in front of the bonnet opening).
Others have used VW parts.
It's just a matter of finding one that fits into the available space & then fabricating some mounting brackets & blanking plates where necessary.
Blanking off top, bottom & sides of the chosen radiator is the important part of the job to ensure that all of the intake air flows through & not around the radiator.
If you're clever in your design the blanking plates double as mounting brackets.

Cheers
John

[memnon]

I have never contributed on this sort of thread before... My opinion appears to differ from common.

S4/Sprint Elans for road use have aenough radiator for the heat the produce. Get it recored with the best core you can. if you can't find anyone local who can help, send it to me and i will get it done at cost on your behalf. last time I got one done it was about ?90

Next remove / move everything from the nose of the car that obstruct air flow, so horns - I replaced with air horns mounted on the N/S, rotate the air filter housing so that it is at about 30 deg to the airflow rather than 90

Next block up the gaps between the bonnet and the radiator tops. I used Medium density foam and cable ties

Finally I created a "ramp" out of ally sheet the goes between the front chassis mounting points (on a sprint) and the radiator bottom edge. I secured it with long 3/8 UNC bolts through the chassis/ body then the ally plate finally with nuts on top.

Despite sustained hard road driving in the summer the temp NEVER rose above 80 and sits at 75 unless you hit traffic.

I have used "I" liberally through this, it was actually a joint effort between myself and my dad .


All the best with it,

Jason Farmer

[redskatejbf]

Alaric, I have in the past suggested on this forum to use the modern Triumph full width radiator (Canley Classics), and this is the route I was going to take, but I had the opportunity to buy a original Lotus full width rad. and did so. However in the `interval` of the purchase I fitted Clives thermostat housing and with the original narrow rad. that had been altered to 3 row ( many years ago ) together with a modern electric fan, I do not get a problem. The fan I purchased at Castle Combe with Merlin Motorsport that fitted easily and the full width rad. I am sad to say is up in the loft, probably making money.
So to sum up I would agree with Rohan.
Regards John.

[Carlos A]

I used a standard Ford thermostat housing.

What is the ref for this thermostat housing?

Thanks

Carlos

[archigator]

I live in Miami, and my Sprint has constantly overheated for years, especially in stop-and-go traffic. I have the original radiator, radiator cap, original thermostat type, original fan and otter switch. Inspired by the look of the Shelby Cobra's oil cooler set-up, I installed an oil cooler a little behind the front grill and below the radiator, leaving everything else stock... works like a champ! The water temperature never hits 90, ever.

Gary
'71 Sprint FHC
Miami, Florida

[Old English White]

...
The TTR "swirl pot" is not really a "swirl pot" being rectangular in shape with radiused corners. It's purpose in life is to provide that "highest point" in the top hose.
...
Blanking off top, bottom & sides of the chosen radiator is the important part of the job to ensure that all of the intake air flows through & not around the radiator.
If you're clever in your design the blanking plates double as mounting brackets.

How does TTR "swirl pot" work :



If you are looking from front trough the grid , you can't see the radiator.
So , as Jason made , having a thin aluminium piece for re-directing the airflow ABOVE the steering rack is very important .
Blanking off top side and bottom is important too , but this should be done with the 2 holes on inner side of wheel arche like on Sprint's.
But on traffic jam , nothing better than a good rad , electric fan and ... alternator !
Christian.

[GrUmPyBoDgEr]

...
The TTR "swirl pot" is not really a "swirl pot" being rectangular in shape with radiused corners. It's purpose in life is to provide that "highest point" in the top hose.
...
Blanking off top, bottom & sides of the chosen radiator is the important part of the job to ensure that all of the intake air flows through & not around the radiator.
If you're clever in your design the blanking plates double as mounting brackets.

How does TTR "swirl pot" work :

If you are looking from front trough the grid , you can't see the radiator.
So , as Jason made , having a thin aluminium piece for re-directing the airflow under the steering rack is very important .
Blanking off top side and bottom is important too , but this should be done with the 2 holes on inner side of wheel arche like on Sprint's.
But on traffic jam , nothing better than a good rad , electric fan and ... alternator !
Christian.

Hi Christian,

thanks for adding that picture, I've never seen that before.
It does appear to have some sort of separater function rather like a header tank on modern cooling systems work.
The "swirl ports" that I was familiar with in the past were cylidrical; mounted vertically with the inlet & outlet stubs welded in tangentially to the wall of the cylinder.
These induce a "swirl" & theoretically the heavier coolant runs around the walls of the cylinder & the lighter air remains in the centre where, when the sysem pressure is high enough, will vent to atmosphere.

Cheers & thanks
John

[Old English White]

Hi Christian,

thanks for adding that picture, I've never seen that before.
It does appear to have some sort of separater function rather like a header tank on modern cooling systems work.
The "swirl ports" that I was familiar with in the past were cylidrical; mounted vertically with the inlet & outlet stubs welded in tangentially to the wall of the cylinder.
These induce a "swirl" & theoretically the heavier coolant runs around the walls of the cylinder & the lighter air remains in the centre where, when the sysem pressure is high enough, will vent to atmosphere.

Cheers & thanks
John

I just made it today ... And that "swirl sport" make that you describe ... turning steam back to hot water before passing through the rad'
Christian.

[alaric]

Hi all. Thanks for all the effort that goes into the posts.

I've always been of the opinion that it's really important to avoid air blocks in a cooling system. In order for the thermostat to work properly i.e. at less than 100C, it should be immersed in the flow of water, and in order for the rad to work efficiently the cores should all be at a high temperature i.e. the water flow rate should be as high as possible, and this latter will be worth its weight in gold for cooling. If the highest point of the system has air over the full cross section, then there'll be a difference in the height of water either side of the air pocket which is a function of the pump pressure, but no flow of water other than by splashing and motion of the engine.

The TTR swirl pot as drawn by Christian looks like it's acting as a compact expansion tank, which is just what's needed and as used in modern cars. It prevents air blocks by ensuring that the fill level at entry and exit is higher than any other part of the system at whatever temperature, with the volume of the pot / box providing enough fluid to take up expansion and contraction through the full temperature range without the fluid level dropping too much. The cut outs in the pipe help trap the air. Excellent looking design.

Sounds like the Cliveboy style replacement thermostat housing is achieving the same from the write ups that I've seen.

Ho hum. Off to town for a coffee with the wife - she's very bored hearing about elan related stuff - poor thing.

All the best.

Sean.

[GrUmPyBoDgEr]

A minor correction there Sean, if I may?
Coolant flow rate is very important but it needs to be regulated in order that the coolant can extract heat from the Cyl.-Head, Cylinders etc. Conversely the flow across the radiator should be so that the radiator works efficiently but not so that it over cools.
Generally speaking a temperature drop of 7-8 C? is the value to aim for. This will prevent the thermostat working "overtime" & limit "thermoshock" effects.
The air flow through the radiator is, as mentioned before, also a major factor determining radiator size.
Speaking generally the coolant flow rate, radiator size & engine power do need to be matched.
Approxiately 1/3 of engine energy is heat that needs to be controlled by the cooling system.
1/3 goes out of the exhaust pipe & the remaining 1/3 drives the car along.
The efficiency here is continually improving in modern cars.
One feature is the electric water pump; the speed of which can be controlled by the engine ECU that uses various input signals to determine the required flow.

As has been previously mentioned, a highest point filling & bleeding point is important.
A raised thermostat housing or "swirl pot" provides this when changing from the original radiator to a "cross flow" radiator.
The original cooling system has the filler cap on top of the radiator & this should be the highest point in the system.
With some cars it helps to place the car on a slope to ensure that the filling / venting point is the highest point. (see level ground)

Regardless of which type of radiator or header tank is used; the basics of coolant filling & exclusion of air pockets should be adhered to:-
1.
Car should be on level ground
2.
Fill the system with the heater controls open (on).
3.
Leave the filler cap off.
4.
Run engine until hot. (normal operating temp.)
Placing your hand on the top & bottom hoses will indicate, that the thermostat has opened, the radiator is working & coolant is flowing through the complete system.
The heater should also be providing a blast of hot air.
Blipping the engine when hot should pump all of the air pockets up to the highest boint & evacuate the complete system of air.

Sorry about teaching Granny how to suck eggs

Good luck with your quest.
John