620R cooling

[CtrMint]

I've been searching around the internet for videos of 620s on track, to see what the temps are like.  I found the following video.  In case anyone reading isn't aware, temp is the center gauge, and 9oclock is 80c.  Look how low the temp is even at the Nurburgring!

Looks like the water temp is about 65c 

[CtrMint]

This one at Oulton equally as cold.

I need to give this up 

[aerobod - near CYYC]

As long as the coolant temp is above the closed-loop lambda operation temperature (60C on my R400D), you shouldn't be getting over fueling when in closed loop lambda operation, should be able to tell with Easimap. If it doesn't stay above that temp after the engine has warmed up, I would say the problem needs to be solved.

[Shortshift]

I don't have a personal stake in this, other than being an interested bystander - but I do think it would be great to somehow come up with some a properly engineered solution.  Particularly if it is capable of retrofit to all cars.

Please persist with this!

James

[ECR]

Like James, I don't have a personal stake in this (and I haven't read and understood the whole of the preceeding). My thoughts are that Aerobod is correct and you need to determine the closed loop lambda situation to satisfy yourself that the engine isn't overfuelling. An essential first step for me would be to compare the temperature gauge reading with the reading via your ECU. In my experience, these can be very different.....

I wouldn't rely on temperature gauge readings alone.

From a test I did on my 2.0VX

Temperature Gauge 7/11/08

Gauge on dash reading 100C Water temperature on Laptop via Easimap reading 89C

[Mark w]

My PC has gone off to Dell for a fix but when it's back I will plug in and tell you what the closed loop fuelling cut off is set at . From memory it's less than 60 but I will check and feed back . 

might take a week or so as it was only collected yesterday and it has gone to Germany ! 

[Shortshift]

Well yes, making sure that the engine isn't running in the warm-up regime is important but I think it will still be far from optimal if it's only running at circa 65-70 degrees (water) rather than 88/100/107 (as my Duratec in the R500 is configured).  Efficiency at these lower temperatures must take a hit, surely?

Plays to my earlier point about the merit of getting to a properly engineered (and set up) solution. 

James

[Doctor]

Working on it James. 

[CtrMint]

The work I did with John Martin as detailed in this months Low Flying showed the ECU and dash gauge to be bang on, at least on the 420.  Looking at the switching point of the fan on the 620, I'd say the 620 also looks accurate.

i really need to finish the logger and as some additional monitoring.  

[CtrMint]

I've also written to Simon Lambert, asking him to take a call to discuss the matter.  Ultimately Simon was very engaging during my 420R build issues and helped with the radiator fitting  and redesign.  I hope he will take the time to recognise that the wider community is looking for some input, even if it's a justification for their design and assurance of longevity.  As yet I've only received an Out of Office.  

[Mark w]

I watched my temp gauge avidly yesterday during the club track day at Brands Hatch .

It was a REALLY hot day and the needle consistently sat at 75-78 degrees .Too low you say BUT i also noticed that the fan was coming on with the gauge showing a tad over 80 ( on the gauge ) .

Even if the car had no thermostat i cannot see how it would consistently run as cold as 75 being thrashed in lower gears on a day when the ambient was up in the 30s .It just doesnt feel right . A  couple of the K series were really suffering with the heat .

I cant wait to get my PC back and plug in Easymap , keen to see what the fan actuation is set at and see if the gauge is showing the same temperature as Easymap is off the other sensor .

PS i saw a post above suggesting readings as low as 40 . Is that right ? My gauge doesnt appear to register temp as low as this , its the bottom of the blue bar .....

 

[Titanium7]

It was mine that read really low but that was when it was quite cold ambient temperatures. Now in the heat it's around the 55-60C. Could be a poor gauge or sensor. With the rad 1/3rd blocked its running between 70-90C in the current heatwave. 90C on the gauge is where my fan cut in.

It's going into Oakmere next week so I will ask them to investigate.

[Doctor]

New gauges ordered. Made pre requisits to run oil temp as well. 

[Doctor]

Blocking 1/3 of the rad in the ambient temp of 30'C does not sound as good engineering. 

[7 wonders of the world]

Agree it's pretty poor having to employ 1960's technology to get things to work correctly.

I'm looking at the pear drop plate for the DS tapped for the oil sender to I will post a separate post for this in order to gauge interest.

Martyn if you could please try to get photos of which stat is being used.

 

[Doctor]

There is an oil filter sandwich plate with the arrangement for two sensors. Arrived today. 

[7 wonders of the world]

Still in the wrong place though..... this is measuring oil temp before it goes into the engine, you will only get a peak temp at the hottest point ie directly after its collected the heat so whens its collected in the sump, before it goes through the cooler and gets returned to the tank.

Which is why I had some plates made for the DS sump.

[Shortshift]

Will be interesting to see more accurate temperature readings (and correlation to dash gauges) when Mark gets his Easimap kit strapped onto his car.

James

[Doctor]

I'll give it a go, it is quite a neat solution. Better than no measurement I guess. I don't run the remote oil filter, the oil getting to the filter is coming directly from the block.

[Mark w]

Guys

If you look at the Caterham parts site the temperature gauge for the 620 is now described as recalibrated .
 

ive asked Caterham when this was revised and the guy that answered wasn't sure so I've put in an enquiry with Caerbont to get the detail . 

Will update everyone when I have the detail . 
 

Have also been working with " Doctor " on a mod to the cooling to reinstate the bypass . Getting there -slowly . 

NEIL 

Do you know the thread sizes for the two sensors that sit in the water outlet on a 620 ? 
 

 

[7 wonders of the world]

Mark,

Just answered Doctor as you may be going down a blind alley ! and missing key elements.

 

[Mark w]

For anyone who wants to check their sensor is operating correctly Caerbont advise me it should give a reading of 250 ohms at 80 degrees .

[Mark w]

Mark,

Just answered Doctor as you may be going down a blind alley ! and missing key elements.

not necessarily a blind alley , possibly a pragmatic interim solution that's not perfect but better than the present arrangement . 

Getting  an additional spigot onto the thermostat back plate without compromising the existing welding and allowing a pipe to be fitted in the confined space available  is very difficult .

[Mark w]

This chap did it .

[7 wonders of the world]

Mark,

Just because it can be done does not I'm afraid make it correct !

Modifiying the current alloy housing can be done to make a provsion for the bottle / heater return, blanking off the current machined bleed in there too, do these and you have a correct system.