620R cooling

[Geoff Brown]

Brian #175 -  Caterham Cars in 2017 summed up in a letter to the club: 

'So, having considered all the above points Caterham Cars Ltd has decided that there is little or no benefit to both parties in continuing our collaboration and, therefore, this should cease. Caterham instead, will aim to foster relationships and support valued customers directly so it may better understand and serve their interests.

Underscoring added for highlighting purposes.

So in relation to some of the content of this thread I hardly have to point out that CC have reneged on every aspect of the above statement. It is such a shame that CC do not take to heart what customers as those here simply require. Dialogue would be a start.

Unfortunately the attitude of some at CC does not lean toward forging relationships or making customers feel valued which makes me wonder how many other 'silent' owners out there want to break free by selling off their Seven?

CTRMINT purchased TWO Sevens so how better understood & valued does that make him?

[Doctor]

 Everyone has had their share of frustrations with CC - I've ordered my CSR R500 in August 2013 and finally drove it off in August 2014 leaking every single fluid the car had onboard. But I didn't give up, knuckled down and sorted the issues one by one. With or without CC. The problems I was having landed me with this club. Once I've sorted all of the issues, I changed it to 620R SV. At first glance, that looks like a bid of an inbred - cooling system and the way CC decided to fuel the engine is truly concerning. At the end of the day we all love driving the 7, it is easy sometimes to forget that it is 1950's design built in the shed. Mercifuly to CC, however, we seem to be even more forgivable customer base than Tesla. The point I'm trying to make is that there is plenty of expertise and knowledge around (outside the club and definitely outside the CC) to address all of the anxieties and real technical issues. And then it's time to pin it down and steer into the slide. 

[ChrisC]

That will tell us a true picture as to how hot/cold does the car really run. 

18 pages about how rubbish the car is, and how rubbish CC is, and a guy complaining his 58K car has only done 650 miles,  blah blah  and the truth is we don't know is there is an issue or not???

Typical Blatchat.  

Personally If it was my car I would want to speak (yes speak) to people that designed the installation, they are on the Facebook groups, and are helpful people. 

[CtrMint]

Firstly thank you everyone that has emailed/pm direct to express your support.  It's appreciated, very much so.

Please don't think I've fallen out with Sevening, absolutely not, I still thoroughly enjoy my 420, the 620 is also an amazing drive.   But I personally need to have confidence in the car, and when you can see the needle actually move down quickly, the faster you drive, you just, well have doubts.  Having a car I can use reliably over the next couple of years on track days is also important.  The cost to come over and do a track day is around 1000.00GBP.  If that's ruined by a reliability issue, then not only is it annoying, but a complete waste of money.  I only get about 2 to 3 chances a year to visit the UK for a track day too, so it's important they go well.  Having the car stuck at a dealer is also annoying as it requires additional trips and costs to travel back to the UK.  Since 2012 I've been using an Exige of various types, and they never let me down.  That's why I think it's better to just go back to Lotus.  The 620R is an amazing car, my reasons for swapping still make sense, it's just come with a higher level of risk than I'm prepared to accommodate.    

[CtrMint]

Chris, 

I don't wish to enter an argument with you, even if there is no concrete evidence on reliability.  There is clear problem when the car gets over cold and the map enters its cold/rich setup, it then starts drinking fuel at an alarming rate.  I'm lucky to get 50miles off a tank.  That is a clear indication there is a problem.  

I'm also not the only new 620 owner experiencing this, see post #156.

[ScottR400D]

Chris, are you suggesting that it might be OK for the 620 to run at 40/50 degrees? 

 

 

[ChrisC]

And what I am saying is you need to take that up with your dealer.  You drove that car back from the dealer to the IOM.  On that drive did you only get 50miles to the tank, because the cooling system design hasn't changed since then?   It is however entirely possible a £5 thermostat has failed or was poorly fitted, but that's what warranty is there for.

You may not be the only owner experiencing that problem, but before the design is questioned, and you take maters into your own hands, consider your car is still under warranty.  Don't give CC a "get out of jail free" card on any warranty claims made with your car.  

If you feel there isn't a fault and the 50miles to the tank is a design problem, I would speak / seek out the people who know, so much more about these car than the hobbiest that comment on forums and facebook (like myself).   You need to speak to people who know.  

As an aside there is no way your car would pass IVA on emissions if lambda wasn't working properly during the test, so it makes me fell like we are talking about nothing more that a failed component, or even a batch of failed components.  

[CtrMint]

Chris,
I'm not sure why you want to be so aggressive in the response.  Again read the entire thread, I'm not the only one.  I'm also not whining, most of the thread has been a highly constructive analysis of the design and ideas to improve the situation.  You seem to have attempted to label the thread unjustly, I'm not sure why.   I've even openly admitted I've not contributed much, as it's beyond my expertise, but I've met many of the contributors and a choose to accept their expertise.   Anyway to answer your questions

Yes I drove it back, it was about freezing on the day.  A rather unnerving situation with the new car on ZZRs.  I managed to hyper mile up the M6 in 6th gear, coasting as much as possible, we just got home on the tank.  I was totally focussed on the traffic, predicting where to be to avoid throttle use, rather than looking at the gauge. I suggest you watch my collection video, you'll notice I sat behind two trucks who were hell bent on racing.  Clearly on island I'm using 3rd and 4th, which is producing totally different results.

I've spoken to CC, I have a response which to some degree explains their view of the design, and I believe indicates my car is behaving as 'expected' as per the design.  It's a 'feature' as a result of the design as far as I'm concerned.  I would suggest the car has been designed with a single focus in mind, balls to the wall track driving. I'm sure at that it will be fine.  That does not in any way meet my use case.  I do not believe its a stuck thermostat, and from CC's response neither do they.

With respect to taking matters in to my own hands, I've expanded on the complexities of where I live, sometimes you just have to acknowledge/accept the draw backs and work within the environment.  

 

[Mark w]

 

Given the recent change in direction of this thread i am going to stop posting here after this post .

The 620R was developed as a track car , originally it had no thermostat and worked fine for its intended use .The design incorporates a massive amount of cooling to deal with constant track use , large radiator, big oil cooler , intercooler and supercharger cooler .As one of the first 7no 620R owners ( who used his "track car " on the road ) i approached CC and asked them to look at introducing an upgrade to include a thermostat .It took from 2014 to 2016 for them to do this but after having this fitted ( FOC by CC ) temperatures were better controlled , not perfect in colder weather ,but better than nothing .It was an adaption to the original design NOT a start from scratch design.

I was happy to " muddle through " with a radiator blanking plate in the coldest weather, i had after all had to do that with my R400 K series previously. My car is  6.5 years old now and has done between 10 and 20,0000 miles. You dont do that sort of mileage without driving a fair bit on the road .Ive not had bore wash issues , its reasonable economical on the road - maybe 30-35 mpg and i know when it needs a bit of help keeping temperatures up. There isnt a need to remove and replace the radiator blanking panel every 1/2 mile , ive put it in driving to a circuit early in the  morning and forgotten to remove it for the first few  of sessions ! , the cars coped fine , it never overheats.

Marks recent thread got me thinking about this again and with Neils help i better understood the Duratec standard cooling system design and the way the 620 has been plumbed . The basic issue is packaging , theres just not much room available for a  third connection to the Duratec thermostat housing with all the supercharger plumbing in the way and the " cold bleed " design CC have adopted with the aluminium housing  isnt optimal for cold weather road use . 

I think there is a design solution to this ( without going to the extreme of an ECU controlled variable speed electric waterpump )  and have ordered a few parts to trail fit , basically i am going to try and eliminate the cold bleed  and introduce a proper bypass and feed the expansion supply into the thermostat housing as Ford intended .

Who knows if i will be successful but i like the challenge .It might be better on the road but overheat on track!!

Posts above about "cars costing £50K  should be faultless " make me laugh . Ask the original owners of £125,000 991 GT3s if their cars were faultless ! The engines grenaded with regularity and Porsche had to stop making them for about a year whilst they tried to find out why .This was the same manufacturer that launched the 997.2 GT3 with centerlock wheels ( one nut to fix )  which kept falling off on track when the hubs cracked under load and collapsed .I had one of those !

These offerings were from the worlds most profitable car maker who has an almost unlimited R and D budget .

Caterhams are an acquired taste , brilliant at some things, poor in others. Everyone has different priorities and those that can adapt their cars to suit their requirements , where they cant they move on .

Igor and i will develop our thoughts and get the alterations manufactured and trialed. If you see me out in January with my temperature gauge showing a steady 90 you will know ive cracked it 

[Shortshift]

Mark (W) and Neil

What about creating a new thread over in Tech Talk?

And, better still, copy and paste some of the key prior posts from this thread over there, so that there's a consistent build through the story.

There's far too much good background information to be lost here, and I'm just one of many (I suspect) who is following your work with great interest.  I'd like to read your updates in teal time through to a triumphant conclusion!

James

[ScottR400D]

#185 'What about creating a new thread over in Tech Talk?'

??? this thread is already in TechTalk.

 

[Shortshift]

"...this thread is already in TechTalk."

Dooh - so it is!  My mistake, getting confused - it seems to happen more and more these days!

In which case I'd simply implore Mark w, 7wotw and Doctor to keep posting as they make progess with their work on developing an engineered solution.  It will be of value to all 620 owners (and potential owners) if they come up with a fix that can be retrofitted. From what I can see, they seem to be on a promising path so far and I want to hear more as the work continues.

James

 

[Shropshire AR]

I may be barking up the wrong tree here but when I had an R500K it also was difficult to control the temperature so i fitted an external PRRT and took the original stat out of the housing. From then on the temperature was a rock steady 80C in almost all conditions. Could this be a viable solution as the whole PRRT package added up to less than £100.

[Doctor]

Any more details about this?

[CtrMint]

Your suggestion got me thinking.  Could you simply short circuit the radiator with a small / narrow loop to ensure hot coolant mixed with cold coming from the cold side of the radiator.  If both hoses going in and coming out of the rad were replaced with hoses with a Y piece, a joining loop and a valve could be installed then hot coolant would always lift the temps.   The valve could be used to stop flow for track work and thus maximise cooling. 
 

Two replacement hoses, a flexible hose, metal joints and a valve seems simple compared to modifying the thermostat housing.  If this is flawed, can you please express why, I'd like to widen my understanding.  

[Titanium7]

The PRRT plumbing is simple and very effective, also the QED remote stat system (have never used this). I've installed the PRRT system on two high power K Series cars and on both occasions it's sorted the issues out. Here it is on the R500

[Titanium7]

The PRRT plumbing is simple and very effective, also the QED remote stat system (have never used this). I've installed the PRRT system on two high power K Series cars and on both occasions it's sorted the issues out. Here's it on the R500

[CtrMint]

My thoughts, 

The valve could be;

https://www.carbuilder.com/uk/15mm-58-heater-valve

or 

https://www.carbuilder.com/uk/solenoid-operated-onoff-heater-valve with a switch installed on the dash, and reversed so it's permanently closed.

If I could have a T joint fabricated with the right dimensions you could probably cut the existing hoses and insert the T piece.  Or something like this, 

https://www.merlinmotorsport.co.uk/p/38mm-aluminium-t-piece-with-16mm-spout-mhj-t38-16

I know this isn't a perfect design, but it essentially provides a form of improved control similar to stalling the rad with blanking tape.  Or am I missing something. 

The key thing here, is this solution if it works, is within my skillset, so something I can tackle in my garage.  The modifications discussed to date are not practical for me.  This therefore offers an interesting option

[Doctor]

What does PRRT stand for?? 

[CtrMint]

Pressure relief remote thermostat?

[Doctor]

I think Caterham run 32mm ID hoses. I think better water (and oil) temp gauge is needed and you will be watching it quite a bit to gauge the right amount of bypass flow. 

[JonT]

If you can use the K-series PRRT unit, that's got the thermostat within the Y joining piece to merge cool rad flow and hot bypass flow. So you don't need a flow restrictor in the bypass pipe, and remove the thermostat into the block.

I've done the same on my K-series, and it seems to work pretty well. You should end up with pretty much constant flow, and the thermostat simply merging hotter (bypass) or cooler (rad). 

[Doctor]

Found it - pressure relieve remote thermostat.

[CtrMint]

When I queried CC on this issue they said that part of the problem is due to the water pressure forcing the thermostat open,  that's the reason for the cut out in the house, I may be wrong but doesn't that mean any thermostat will be forced open and hence negate its use?  That's part of the reason I considered a manual control valve such as the heater valve.  It would be nice to find an electric valve, and couple that with a simple circuit and sensor post mixing, that way the management could be automated.  Again within my skillset :-) 

 

[CtrMint]

An updated version of the idea,