TomGaval Posted October 10, 2014 Share Posted October 10, 2014 My lastest addition to the garage, a second Caterham. is a very high spec SV with a Cosworth 2.3L duratec, with 13:1 compression ratio, that has been suffering from a pressurization of the coolant in the expansion tank which then pukes out a little coolant usually after 15 to 20 minutes on track.I feared the dreaded Head gasket, and as My other car has a roverK series, I'm well versed in the history and dealings with Oily. I had the system tested for exhaust gases in the coolant, but the test was negative. I found two small leaks in the Radiator, and had those repaired, and I removed the thermostat as the lower hose was not getting warm. Fan works and comes on at 195F. On track yesterday, during the first session the car ran well for about 15 minutes of spirited driving and then the temp started rising from the steady 185F to wards 220. I backed off and went in and the temp was back down by the time I got to the Paddock. A small spray of coolant was visable on the expansion tank, cam cover, dry sump tank and even back as far as the scuttle. On the remaing runs yesterday, I held max revs to 5500 on one session and then 6500 on the next session. At 5500 rpm max, the car made the whole 30 minute session without issue, no coolant leakage, no temp above 200F. At the 6500 level, the temp came up again to 220F but no coolant leakage. Today I ran it hard, in all sessions, and Revs got into the 7000+ range often. On the first two sessions this morining I could run hard for about 4 laps, (2.25 mile track) before the temp got to 220F but once I lifted and slowed down a bit, the temp would get back to 185F and then I'd go at it hard for another 4-5 laps till it did it again. Every time when I lifted off the throttle the temp came back down. The last session today I did about 8-10 laps before it hit 220F. So after that lenghty description, I'm concerned that the temp keeps rising if I don't back off. I should be able to get thru a 30 minutes track session without overheating. Any suggestions as to what the issue could be? Tom Link to comment Share on other sites More sharing options...
sjmmarsh Posted October 11, 2014 Share Posted October 11, 2014 Have you tried replacing the expansion tank cap? They can fail which can cause the leak you describe. My CSR was spraying some coolant from the cap but stopped once I changed it for a new one. It may not solve the overheating, but it is a quick and cheap fix. Steve Link to comment Share on other sites More sharing options...
SM25T Posted October 11, 2014 Share Posted October 11, 2014 Second the cap suggestion. Cheap too. Does the fan run in the right direction ? If not, reverse the wires to it. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 As above.But it does seem to depend on the power and does cool down quickly... what sort of radiator is it and how do you know it's up to the job?What sort of oil cooling do you have?What coolant are you using?Jonathan Link to comment Share on other sites More sharing options...
sjmmarsh Posted October 11, 2014 Share Posted October 11, 2014 Jonathan - yes, I noticed that the engine seems to overheat on full load only. Interestingly, the CSR has the same engine and normally exhibits a drop in temp when revving the engine hard, apparently because the pressure from the water pump rises and holds the thermostat open.This suggests that there may be inadequate cooling for this setup - either a radiator under spec, pump not adequate or a blockage somewhere?Steve Link to comment Share on other sites More sharing options...
F355GTS Posted October 11, 2014 Share Posted October 11, 2014 Hi TomIf it's not the cap, I used to get very similar symptoms on the high power VX and others have as well inc ECR, Paul Gibb etc. Nick Dinsmore designed a solution with a swirlpot in the top hose to replace the expansion tank, this cured the problem permanently. Might be worth consideration Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 ... a swirlpot in the top hose to replace the expansion tank... What's the idea behind that?ThanksJonathan Link to comment Share on other sites More sharing options...
Croc Posted October 11, 2014 Share Posted October 11, 2014 Interestingly, the CSR has the same engine and normally exhibits a drop in temp when revving the engine hard, apparently because the pressure from the water pump rises and holds the thermostat open. This suggests that there may be inadequate cooling for this setup - either a radiator under spec, pump not adequate or a blockage somewhere?This is clearly the situation. Tom and I run together on track. I dont have any problems with my CSR and he does, albeit with an extra 35hp over me, we have the same engine. Tom's car started life as an R400 with a 2L Duratec which the previous owner upgraded by changing engines to this spec. I dont recall the radiator being changed in that conversion and have no idea on the water pump. I did not think that the R400 used a different water pump/radiator to the CSR? I know Tom has replaced the cap already so we can rule that out. Link to comment Share on other sites More sharing options...
TomGaval Posted October 11, 2014 Author Share Posted October 11, 2014 As Croc said, I have replaced the cap, But I have another and I'll replace it as a precaution. The radiator is the C400 race version, so it is upgraded from the standard one. Don't know what coolant is in there as It was replaced before I bought it. As for the oil cooling. there is an oil cooler mounted at the front on the lower third of the radiator. Oil temp takes a few easy laps to come up but when running hard it sits right around 200F. When I backed off the throttle to cool down the water temp, the oil temp dropped down to around 180F. I have the triangular dry sump tank mounted in front of the engine. Mark, any pics and details available of the swirl pot set up? Oh, And I saw that the F60 America is all sold out, are you one of the lucky 10?* My wife still tells the story of you picking me up in the 308. Thinking I'm a loon getting in a car with a complete stranger. Thanks for the help guys. Keep em coming! Tom Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 Let's separate the discharge of coolant from the operating temperature.What temperature should this engine run at on the track?The radiator is the C400 race version, so it is upgraded from the standard one. I don't know anything about these: can someone confirm that it should be adequate?Don't know what coolant is in there as It was replaced before I bought it.I'd replace it immediately with something that I knew to be appropriate.Jonathan Link to comment Share on other sites More sharing options...
F355GTS Posted October 11, 2014 Share Posted October 11, 2014 this thread may help Jonathan, problem is the expansion tank is not high enough so air don't naturally get to it and get's trapped in the rad hence overheating and blow by on cap. I wonder if it's been caused by the 2.3 beign fitted which is taller than the 2.0. Thread http://www.lotus7.club/forum/techtalk/vx-water-swirl-pots-any-pics ECR (Roger) is just fititng one to his VX and has the tech drawings to make one Tom F60 thingy is a tad outside the budget Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 Thanks. I've been reading about swirl pots, but I don't know anything about this engine.What's the relative height of the expansion tank, the outlet from the radiator and the highest vent on the radiator?Where is the air coming from that is going to be extracted in the swirl pot? The maximum temperature observed is 104° C and with the right coolant that's well below the boiling point. (I'm also generally dubious about there being "hot spots" causing local boiling within modern engines.) And it looks as if the head gasket hasn't failed so excess pressure from that isn't likely.But if it isn't possible to get an expansion tank and associated bits to stop leaking then I do understand that not having one would help!Jonathan Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 Relevant recent discussion here. (Ignore the thread title.)Jonathan Link to comment Share on other sites More sharing options...
TomGaval Posted October 11, 2014 Author Share Posted October 11, 2014 Thanks for the pointer to that link Jonathan. Roger's issue sound very much like mine. The location of the expansion tank is on the right front next to the dry sump tank. As pointed out in an earlier thread I started the tank is below the level of the head and is definately not the highest point in the system. I might be able to find room on the scuttle on the left side. I have the paddleshift compressor and valving mounted on the right and center of the scuttle. Hopefully Roger will see this thread and post a drawing or picture of his solution. (hint, hint.) Tom Link to comment Share on other sites More sharing options...
F355GTS Posted October 11, 2014 Share Posted October 11, 2014 That's the thread I was looking for Joanathan but couldn't find it due to title As he says it's the same problem I had and the swirl pot cured it Hope you get it sorted Tom Link to comment Share on other sites More sharing options...
ECR Posted October 11, 2014 Share Posted October 11, 2014 Hi TomJust fitted Nick Dinsmores swirl pot to my engine in readiness for a test at Dijon on the 23rd. I'm confident that it will work for my engine as it has for everyone else who has fitted it (mostly to VX's but to one K series also). If someone can tell me how to post pics I'll do that or alternatively, if you confirm your email I'll mail direct Link to comment Share on other sites More sharing options...
Pat the Plumber Posted October 11, 2014 Share Posted October 11, 2014 could we have some photo's of the plumbing with "swirl pot" please*scratchchin* Link to comment Share on other sites More sharing options...
ECR Posted October 11, 2014 Share Posted October 11, 2014 I have pics of Nick's swirlpot fitted to my car so if someone can explain (simply ...) how to get them onto a post I'd be more than happy to oblige(that's the emoticons sorted then ....) Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 Roger: Do you already use a photo hosting service?Jonathan Link to comment Share on other sites More sharing options...
F355GTS Posted October 11, 2014 Share Posted October 11, 2014 Roger if you email the pics to me I can post the linksemail me Link to comment Share on other sites More sharing options...
ECR Posted October 11, 2014 Share Posted October 11, 2014 On their way Mark JonathanYes I do (dropbox) and I'd be happy to know how to post for the future. Link to comment Share on other sites More sharing options...
ECR Posted October 11, 2014 Share Posted October 11, 2014 Pat Sent details to your address but it bounced for some reason. Mark has the same and will be posting here for all shortly. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 OK: Get them on Dropbox. Then follow these instructions. Then tell us that URL and we'll see what we can see.Jonathan Link to comment Share on other sites More sharing options...
F355GTS Posted October 11, 2014 Share Posted October 11, 2014 Pics belowhttp://www.collinsclan.co.uk/swirlpot/1.jpghttp://www.collinsclan.co.uk/swirlpot/2.jpghttp://www.collinsclan.co.uk/swirlpot/3.jpghttp://www.collinsclan.co.uk/swirlpot/4.jpg Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 11, 2014 Member Share Posted October 11, 2014 All 4 work for me.:-)Jonathan Link to comment Share on other sites More sharing options...
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