Duratec Coolant issue Resolved!!!!

[F355GTS]

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[Jonathan Kay]

... as do the inline images!

Jonathan

[TomGaval]

Update.    I drained and flushed the system and refilled using EVAN's Coolant.  It's a waterless coolant that claims a 375F boiling temp that helps prevent hot spots due to boiling. 

I did two trackdays this weekend and I'm happy to report that the coolant level remained stable and there was NO leaking/Puking out of the expansion tank. 

The bad news is that I still have an overheating issue when running hard for several laps.  The Air temp this weekend was in the High 50'sF and the coolant temp still hit 220 after about 6 laps running hard. It would quickly cool to 210-200F by lifting. 

One of the other members at the track suggested moving the oil cooler from infront of the radiator, and to try some sheet metal ducting from the radiator to the nose cone to ensure no leakage of fresh air around the rad.   Also suggested a small bleed vent drilled in the top radiator bolt, with a line to the expansion tank.   

I maybe able to fab up some ducting before next weekend's trackday.  Will keep you posted.  Tom

[2GBR]

Are you sure the water pump pully is the correct diameter for sustained high revs ? As if to small will be cavitating and not flowing and also if flowing to fast it is not cooling either. 

[Jonathan Kay]

What's your target maximum temperature? What do others with similar set-ups see?

Jonathan

PS: I'm very sceptical about Evans waterless coolant having any beneficial effect in most 7s in most conditions. 

[Simon.Rogers]

Jonathan

You keep saying your sceptical about Evans. Yet all the evidence from members on here who have used it provide the evidence in their installation an usage which proves it works.

Tom has confirmed it stopped the pressurisation which therefore logically must indicated there was localised boiling in the engine.

It clearly has not solved the inherent problem that cooling is an issue.  That's not my point though.

it may not be necessary for most 7's or indeed any car but when you look at the advantages and long term cost savings on coolant and lack of corrosion to parts in the system with no known negatives why you continue to knock it I find confusing.

when you have used it and suffered a negative experience because of it may be I will take note of you comments about it.  Until then I will just be skipping you posts.

Yes I do sell the stuff.  No I am not that bothered because I have not sold enough of it to make me enough profit to refil my own car.

Yes I do use it.

[Jonathan Kay]

Thanks, Simon.

I'm sceptical for two reasons:

1 The explanations of the physics that are used.

2 The results that people report. But I may well have missed something: what are the best results and evidence that I should be looking at?

Tom has confirmed it stopped the pressurisation which therefore logically must indicated there was localised boiling in the engine.

I'd be much more inclined to think that the change of coolant was the cause if he switched back and the problem reappeared... otherwise it could be due to something else, such as better filling and bleeding.

Jonathan

[TomGaval]

Jonathan, I can pretty safely say that after draining and refilling the system 3 times that it was done correctly each time.  I took significant care to make sure it was bled well and would idle for over 35 minutes without any temperature issues before taking it out on the track.  The EVAN's coolant definately cured the pressuriztion issue.  Yes, to be scientifically correct, you would revert back to the old coolant and see if the pressurization reoccured, but The swtich to Evans was costly enough, that I don't want to spend the extra money at this time.  My other Caterham has a K series, so I'm pretty confident in my ability to bleed a coolant system after 15 years of ownership. 

Like I said, I'll try the ducting around the radiator before next weekend's trackday to see if that helps the cooling.  Then do a few of the other suggestions, before the final track weekend in two weeks.  The car will then go into the shop at the end of the season for a thorough going over.

I don't have any links to Evan's coolant.  One of the other members of the drivers club at the track has an R500 that had a puking issue  as he came into the paddock after a 25 minute session on track.  He switched to Evan's and it resolved that boiling over issue, so that's why I gave it a try.   I'm just glad it wasn't my head gasket.       Tom

[Jonathan Kay]

Is it overheating?

Cooling

The handbook (for the standard engine) says "The optimum operating water temperature for your engine is 110°C." (230° F.) Should that be different because of your state of tune? From what I can tell in this thread yours has never got that hot. But the temperature is still rising as you increase power rather than becoming stable.

I think the highest oil temperature you've seen is 93° C (200° F). The handbook recommends a maximum of 120° C. 

What's the oil temperature after the change of coolant?

Pressurisation

I'm still interested in why it was discharging coolant. Did you change the pressure cap before changing the coolant?

Jonathan

[6speedmanual]

Hmmm. Interesting discussion.

I too would like to know if the cap was replaced before changing to Evans.

Is a solution being sought to an overheating problem which is not actually present? (ref JK's comments on the temperatures attained). Correctly functioning cap could have fixed it.

Whilst I am sure cooling systems can run on many different liquids/mixtures including Evans, each has pros and cons. But fundamentally a motor such as yours Tom shoukd be able to run on conventional coolant and system. Therefore I suggest some issue not fully resolved (eg the cap not containing boiling). Use of Evans which has one characteristic of high boiling point at atmospheric pressure is an expensive way of masking what may be a simple and easily rectified fault.

Peter

[elie boone]

Tom, the temp you mention are these the one's the gauge shows of measured infra red or with a probe ? A friend of mine has a SV 2.3 D Raceline (220bhp ish) and had some temp issues on the motorway, fine in traffic. After i put a cowl arround the rad all was fine.

[geko]

Hi,

this is what Cosworth say about there 2,3 Duratec 260 hp:

Coolant Temperature above 5000 rpm:
75°C ± 5°C Track
85°C ± 5°C Road

Maximum Coolant Temperature 95°C

 

 

 

[Jonathan Kay]

Cosworth say: "For sustained high speed use, a low speed water pump pulley helps to reduce pump cavitation and maintain a constant flow of water."

Do you have one of those already?

Jonathan

[Croc]

I too would like to know if the cap was replaced before changing to Evans.

Tom was running on track yesterday and given who he was at dinner with last night he will be badly hungover today.   But I can confirm that he has tried a new cap (multiple from memory) before going to Evans.  I agree totally with 6speed's observation - it should just work.  Having witnessed Tom's experiences firsthand at the track I can see that the system is always pressurising with air.  

Jonathan's observation on water pump is matching my suspicions as once you eliminate the possible causes of head gasket, hose plumbing, cap, thermostat, proper bleeding, catch tank location then there is not much left it could be.  It was an R400 originally but I dont know if the waterpump was transferred across when the Cosworth was installed or whether it was a new Cosworth waterpump - should be an easy check though when he sobers up.  

[Jonathan Kay]

Tom was running on track yesterday and given who he was at dinner with last night he will be badly hungover today.

... I blame the waterless refreshment!

:-)

Jonathan

[Pendennis]

My Duratec is only used for circuit racing, coolant never reaches 95c. The optimum coolant temperature for my engine is between 84-90C. Unless the ambient is up around 30c it generally holds it at 85C easily.

During a 40 minute race in ambient approaching 33C the coolant never gets above 90C. I have more worries with the oil temperature to be honest. I have seen the oil at 105C which is too high, but the coolant would still only be at 90C. 

I do use the oversized water pump pulley but if I am totally honest I have never seen cavitation on my Duratec engines during 10 years of circuit racing. I have experienced air locking within the circuit which causes these symptoms. My set up being a race car is very basic, I use the Raceline water rail and pre-heat bypass setup, no header tank which I have seen cause issues such as this. I also do not cowl off the radiator, I could see this method creating other issues which possibly cancels out its purpose.

[Pendennis]

Tom, I remember your other thread during which it was established your header tank was below the level of the head. You stated on 11/10/14 that you still have not raised it, is that still the case? If you haven't your wasting your time looking for other reasons.

PS. My engine is at 8500rpm. My rad is the Radtec double core, oil cooler is separate air to oil 13 row type.

[6speedmanual]

Cavitation at pump should not cause the coolant pressure to increase.

Cavitation is the localised vapourisation of the liquid on the low pressure surfaces of the driven impellor. The craetion of a pocket of vapour which then collapses can cause impact damage to impellor and the surrounding casing.  It's a long term errosion effect. The effect of this can sometimes be seen when stripping down water pumps.

Any cavitation pockets of vapour created in the pump will have collapsed long before they travel around the cooling system.  These are totally different from air bubles or airlocks which can cause localised lack of coolant contact with hot surfaces (like cylinder head) and therefore result in localised overheating and boiling of the coolant.

Alternative coolant liquids with higher saturated vapour pressure may be more resistant to cavitation and therefore may be  better for the pump, if indeed this is actually a problem and not just a theoretical situation.

Any alternative coolant liquid can have airlocks or bubbles as this is usually a condition from the design of the cooling system, its ability to be bled or to self bleed in operation.  Once there is a bubble with no contact with the heated metal surface, the temperature in that area will rise. Not sure how/if Evans can make any difference to this, other than if the bubble then colapses, the higher boiling temperature may help.  But better not to have the problem in the first place rather than mask it.

Peter

[TomGaval]

Croc was right.  Hung out with a bad crowd last night at dinner.  Waaay too many bottles of wine. 

I did change the cap prior to the switch to Evans. I have another new one I'll switch to.   I have not yet moved the expanion tank and now that the trackday season is over, that is on the list of winter to do items. 

Yesterday's air temp at the track started at 28F and got all the way up to 40F.  Coolant level rose slightly in the tank but never puked.  Although there were a couple small droplets on the tank around the cap.

Temp got up to 205 during the first session and  did briefly hit 220F during the 3rd session of the day.  Temps are from the gauge, but I did check the gauge temps vs an IR reading at idle and the IR reading at the hot spot on the back of the head near the sender was within 5 degrees of the gauge.  189 vs 185. 

Anyone know what size waterpump pully is the correct one for this application?    I've looked at the SBD website and they have a diagram of the cooling system layed out for their electric water pump installation that looks interesting as it incorporates several bleed points.

Tom

[7 wonders of the world]

Linky ot CFM copy

http://www.c-f-m.com/performanceparts/pc/CFM-Underdrive-Water-Pump-Pulley-for-03-11-2-0-2-3L-Duratec-Focus-111p92.htm

 

[7 wonders of the world]

OE pulley is 100mm diameter

Cosworth version is 125mm diameter

CFM offer a Cosworth copy linky below on your side of the pond

http://www.c-f-m.com/performanceparts/pc/Cosworth-Water-Pump-Pulley-for-03-07-2-0-2-3L-Duratec-Focus-p842.htm

or

Burton over here offer the Cosworth version for £116

 

If you can get one Of Ammo's version as it engineered out the failure point on the Cosworth design.

[7 wonders of the world]

or cheaper still here both from a US seller:

for the solid front version:

http://www.ebay.co.uk/itm/Massive-Under-Drive-Light-weight-Aluminum-Water-Pump-Pulley-Duratec-2-0-2-3-UDP-/261073653656?pt=Motors_Car_Truck_Parts_Accessories&hash=item3cc933cf98

 

[Pendennis]

If your only revving to 6500rpm your not going to see any cavitation, my 2.0L is at 8000rpm all the time and not convinced it's ever done it. The 2.3L generally has power lower down the Rev range so I'd be surprised if you need to rev over 8k?

Have you any pipes or part of the engine which has coolant in it that is higher than the level of water in the expansion tank? If you have then it can only suck air in. The level of coolant in the tank must be higher than any part of the engine.

[Jonathan Kay]

In general if you have a fluid and impeller on the point of cavitation what would be the effect of increased viscosity? (I have no idea if this is relevant to Tom's engine.)

Jonathan

[TomGaval]

Thanks again guys.  First order of change is to move the coolant tank up to the highest point in the system.   I don't think I've been able to keep my right foot down long enough to ever get above 7200rpm.  As Croc said, I'm a big chicken.     I will also replace the cap again, and install a small bleed line off the top bolt in the radiator.  Hopefully that will solve the issue.  Unfortunately I probably won't know the results until next spring, as it takes a few hard laps to have the issue.    Blat Chat Rules!!!    Tom