Overcooling!

[Richy-dick]

I have solved the overheating problem I asked the list about.
I purchased a blanking plate for below the radiator ( from Paul Matty
Sportscars (5UKP)) but haven't fitted it.
I replaced the broken sensor for the Kenlowe fan (25UKP) - not causing the
over heating but a nuisance anyway.
I also had the core replaced with a 3 row core (65UKP).
Jobzagudden (as we say round here).
Around town and in the built-up areas the temperature stays at 89 degrees
unless stationary, in which case the temperature climbs up to the point
where the new Kenlowe temp sensor cuts in at 95 degrees with the fan, when
the temperature is maintained or drops slightly. It then drops back to 89
degrees when I start moving again. Exactly what I wanted....EXCEPT....when
I start going a bit faster, fast 'A' roads or Motorway, the temp drops down
to 80 or even 79 degrees. I am going to have to blank off part of the super
new radiator in order for it to maintain the correct temperature when going
quickly.

Richard A Clifton
Wakefield

[Stevie-Heathie]

Richard, have you got a thermostat fitted? If so, what temperature
rating is it?

Steve
1970 Plus 2S

[paul_adamson]

<snip>
Exactly what I wanted....EXCEPT....when
I start going a bit faster, fast 'A' roads or Motorway, the temp drops down
to 80 or even 79 degrees. I am going to have to blank off part of the super
new radiator in order for it to maintain the correct temperature when going
quickly.

Richard A Clifton
Wakefield
----
Richard
There should be a thermostat that stops the water entering the core utill it is hot enough. I seem to think that this should be 85degC on a twink.
It sounds as though you might not have one fitted, or it might be running a bit low in temp. test with a pan of water and a thermomiter..

I remember when my brother used to race a Mini spending an interesting evening finding the thermostat with the highest click point as this gave the most power off the engine

Brian
---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1

[jimfixit]

I installed a 3 core radiator, high performance thermostat and one of those
yellow blade fans. My elan is now overcooling. At an idle, I can get up to
80 deg but when I get going, it drops down to 70 deg. If I push it, It
takes a while for the temp at the thermostat to get warm and therefore a
delay in cooling. You can tell when the stat finally opens because the temp
suddenly shoots to 100 deg then back down to 80. I assume it's not good for
the engine to be going through such temp variations. I'm planning on
modifying the cooling circuit by putting in a bypass like they have in newer
cars. That way, the engine temp remains constant. Any thoughts
jimbo
s3 fhc
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Wednesday, July 28, 1999 9:30 AM
Subject: Re: [lotuselan] Overcooling!








most power off the engine

[Richy-dick]

I have got a thermostat fitted which I checked to be opening in the late 80s
(that's degrees not years). The fact that the temp stays at 89 degrees
under unstressful driving conditions proves that this is working OK.

Richard A Clifton
Wakefield

----- Original Message -----
From: Steve Heath <[email protected]>

----- Original Message -----
From: <[email protected]>

[paul_adamson]

I the temperature sender take off is <memory a little fuggy> located below the thermostat on the engine side.

This means that it is measuring the temperature of the water in the block / head. When this water is too warm it allows it to pass to the radiator. There is a bypass that goes from here back into engine water jacket to allow the pump to circulate the
water.

Thus if the water in the block is colder than it should be there is

1) a problem with this valve
2) the engine is being cooled form somewhere else....
3) the engine is running very rich - thus not generating enough heat


Some tests to do..
1) Start the car cold and check the temperature of the flexible connection from the top of the thermostat to the radiator. This should remain quite cool till the engine reaches operating temperature and then the pipe should be hot.
the transition is quick, <the pipe will burn so be carefull>
2) The one thing that will cool the engine is the cabin radiator.. Is the valve for this stuck open? With the blower running? This will make 5 - 10 deg difference in the engine temperature.
2b) There is now so much air flow past the radiator that the block is self cooling. In which case the best thing might be to fit the ducting that you purchaced whigh will force the air through the radiator slowing it down. Maybe also providing some
ducting at the back of the radiator to expose less of the block to the air flow. this would allow the radiator to be used when needed. I suggest that you keep the air flowing past the exhaust system.
3) If the top end is running rich this will tend to generate less heat and cool the engine. I can't remember which carbs you have (Weber 40DCOE18 s were standard on an S3 I seem to think).. But it might be worth checking the top end tune as this will
cost you power, fuel efficency, excess wear and heat.

Hope this helps

Brian
--
I have got a thermostat fitted which I checked to be opening in the late 80s
(that's degrees not years). The fact that the temp stays at 89 degrees
under unstressful driving conditions proves that this is working OK.

Richard A Clifton
Wakefield

---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1

[Jim.Normile at snapondiag]

I have experienced the rapid rise and drop in coolant temperature on my Elan
and on another car. Since the other car was a race car with a restrictor in
place of the thermostat; I do not think the thermostat is the problem. My
conclusion was air in the system. When I would make a rapid left-right, the
"bubble would pop" and the temperature would return to normal within 2
seconds.

[email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]]
Sent: Thursday, July 29, 1999 2:54 AM
To: [email protected]
Subject: Re: [lotuselan] Overcooling!


From: [email protected]

I the temperature sender take off is <memory a little fuggy> located below
the thermostat on the engine side.

This means that it is measuring the temperature of the water in the block /
head. When this water is too warm it allows it to pass to the radiator.
There is a bypass that goes from here back into engine water jacket to allow
the pump to circulate the
water.

Thus if the water in the block is colder than it should be there is

1) a problem with this valve
2) the engine is being cooled form somewhere else....
3) the engine is running very rich - thus not generating enough heat


Some tests to do..
1) Start the car cold and check the temperature of the flexible connection
from the top of the thermostat to the radiator. This should remain quite
cool till the engine reaches operating temperature and then the pipe should
be hot.
the transition is quick, <the pipe will burn so be carefull>
2) The one thing that will cool the engine is the cabin radiator.. Is the
valve for this stuck open? With the blower running? This will make 5 - 10
deg difference in the engine temperature.
2b) There is now so much air flow past the radiator that the block is self
cooling. In which case the best thing might be to fit the ducting that you
purchaced whigh will force the air through the radiator slowing it down.
Maybe also providing some
ducting at the back of the radiator to expose less of the block to the air
flow. this would allow the radiator to be used when needed. I suggest that
you keep the air flowing past the exhaust system.
3) If the top end is running rich this will tend to generate less heat and
cool the engine. I can't remember which carbs you have (Weber 40DCOE18 s
were standard on an S3 I seem to think).. But it might be worth checking the
top end tune as this will
cost you power, fuel efficency, excess wear and heat.

Hope this helps

Brian
--
I have got a thermostat fitted which I checked to be opening in the late 80s
(that's degrees not years). The fact that the temp stays at 89 degrees
under unstressful driving conditions proves that this is working OK.

Richard A Clifton
Wakefield

---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1



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------------------------------------------------------------------------

[sbeard at rocketmail.com]

Richard,



Yes, this indicates that the thermostat is not stuck
shut, but the low temperature at highway speeds
indicates that it may be stuck open. It still may be
worth removing it and testing in boiling water.

My experience with thermostat testing is that they
open smoothly over a few degrees of temperature
change in the boiling water test.

Best Regards,

Steve Bearden
'69 Elan (no where near running)

[sbeard at rocketmail.com]

Richard,



Yes, this indicates that the thermostat is not stuck
shut, but the low temperature at highway speeds
indicates that it may be stuck open. It still may be
worth removing it and testing in boiling water.

My experience with thermostat testing is that they
open smoothly over a few degrees of temperature
change in the boiling water test.

Best Regards,

Steve Bearden
'69 Elan (no where near running)

[sbeard at rocketmail.com]

Richard,



Yes, this indicates that the thermostat is not stuck
shut, but the low temperature at highway speeds
indicates that it may be stuck open. It still may be
worth removing it and testing in boiling water.

My experience with thermostat testing is that they
open smoothly over a few degrees of temperature
change in the boiling water test.

Best Regards,

Steve Bearden
'69 Elan (no where near running)

[paul_adamson]

I checked last night and the valve is supposed to be fully open at 88 degrees

Brian

---------------------o0o------------------
Brian Scally - Philips Semiconductors Systems Lab. Southampton UK
tel : +44 2380 312654 fax : +44 2380 316303
mailto:[email protected] seri : bscally@ukpsshp1

[BrianMartley]

Hi folks - my 2p worth on cooling !

I have an 82C thermostat in my car. Most times the car runs between 85 (ish)
and 90. The radiator has been re-cored but with nothing fancy, the fan is on
manual switch and I switch it on the minute I hit any traffic queues before
the temperature rises.

Any cooling problems (had the odd one.... ) and I tend to stick the
thermostat in a pan on the cooker and heat up slowly with a thermometer in
the pan. I find the stats tend to open very accurately and slowly, and
honestly have rarely been the problem, it's usually been elsewhere - once it
was Bar's Leaks (as in official manual) which was clogging up the rad and I
had to re-core. After that, it was fine.

I seem to recall an article in CCC in the 70s about tuning a twink - they
found most power was between 70-80C and it dropped off as it got hotter -
denser fuel mix ? Lotus did list 71C and 78C thermostats in the official
parts lists in the 70s when I got my parts manual.

Brian

[Richy-dick]

Steve

I mentioned in the 'Overheating' post originally that I had checked the
thermostat and it was OK.

----- Original Message -----
From: Steve Bearden <[email protected]>



Brian

The heater was switched off. I know that this gives an extra 10% or so of
cooling so I made sure it was off.

Richard A Clifton
Wakefield

[Richy-dick]

----- Original Message -----
From: Brian Martley <[email protected]>

Does this mean I shouldn't worry about the low temp at speed? I'd be much
happier if this were the case!

Richard

[BrianMartley]

Richard,

About operating temperatures for the elan;

I've just looked through the pile of junk I call a filing system and.....

Article was by Dave Vizard, CCC, 1973... (what a memory ! hopeless at work
but I can remember the important things)
and was about a rolling road session with an S3.

quote

"most of our runs were taken at a temperature of 70C because this is the
best for horsepower on the twin cam engines"

the engine (standard car I think) gave around 75bhp at the wheels - first
tweek was to put in some 32oz spring points, then N7Y plugs then retarding
the exhaust cam 1 tooth to give more overlap at TDC - with a warning not to
try this at home - and they ended up with 83 bhp. Which they reckoned was
what the SE engines usually gave.

If you're interested I'll scan/ocr it at the weekend - pictures will be
lousy because it's b/w and poor - but the graphs should be ok ?

Brian