V7 SLR Posted August 2, 2003 Share Posted August 2, 2003 We experience some outrageous temperatures during the Italy tour which led to my observing some "discussable" phenomena. My setup is a high powered DVA'd VHPD with laminova plumbed into the output from the dry sump scavenge pump and the heater bypass circuit. I have the large 4-core single pass (I believe) alloy race rad and a 76 degreee thermostat. On the way down my self-wired circuit to switch the fan in and out with the M3DK failed owing to my poor workmanship. With the assistance of some loaned tools (thanks Steve Wiseman) I got it working again, however this was not until I saw the coolant temp hit the mid 90's in traffic. At this point I escaped into a side street and shut down. Since repairing the fan switch circuit I was pleased to note that even in extreme temps found on the motorways when stuck in stationary traffic, the coolant never exceeded 91 degrees. The fan appeared to be able to hold it at that. The strange observations centre around the fact that I believed my radiator to be massively over capable, able to sink heat from both the cooling system and the oil system (via the laminova). The fact that I have a 76 degree thermostat means that my temp ought to remain at 76 degrees no matter what. If the cooling system were marginal then I'd expect it edge upwards but never below 76 degrees. I am willing to believe that the temperatures experienced in Europe were somewhat excessive but when driving through the mountains and at night the engine temp falls to a low-peak of 69 degrees. I can't work out why. At all times the oil temp remained between mid 60s and late 80s although I am now no longer convinced how closely the laminova ties the coolant and the oil temps together. If I go on a future "hot" tour, I will exchange the laminova for a thermostatically controlled oil cooler although where I could site it is a bit problematic. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Edited by - V7 SLR on 2 Aug 2003 16:23:18 Link to comment Share on other sites More sharing options...
TorAtle Posted August 2, 2003 Share Posted August 2, 2003 Don't trust the water temp gauge - 69 degrees *could* be 76, mine underreads by 4-5 degrees. Up here in chillier Norway we had a bit over 20 degrees today on a track day. After about 5 laps my head gasket went, and the water temp was a bit under 90 degrees (so in fact could be 93). I have heard that Minister say they never like to see even 80 degrees on a race engine. At any rate I think I'll go for a Radtec before I'll use my engine in anger again - I'm running with the old copper one. Under what conditions did Hooper's gasket die? Link to comment Share on other sites More sharing options...
timbo Posted August 2, 2003 Share Posted August 2, 2003 good to see your back and in one piece V7. Tor - you can't still be blowing head gaskets - I remember back in '99 in Ireland!!!! Surely not fame academy on again Link to comment Share on other sites More sharing options...
TorAtle Posted August 2, 2003 Share Posted August 2, 2003 Timbo, yeah, and if anyone could tell me why I'd be very glad. Something like ' you just can't use that old little radiator' would do nicely. Link to comment Share on other sites More sharing options...
timbo Posted August 2, 2003 Share Posted August 2, 2003 I think raceline do a up rated steel headgasket for the K - not cheap though!!! I am going Radtec aswell - being all aluminum I can run OAT neat (no heater) How old is the copper rad? As you asked "you just can't use that old copper rad" 😬 Surely not fame academy on again Link to comment Share on other sites More sharing options...
V7 SLR Posted August 2, 2003 Author Share Posted August 2, 2003 I have Spa gauges so I'm pretty certain the temperature reading was accurate. Hoopy's head gasket failed in a most strange way. The rubber around one of the coolant holes peeled off the steel gasket releasing coolant. Fortunately this leaked coolant outside of the engine in a most visible manner. After a gasket replacement he was able to rejoin the tour nor the worse (apparently). Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Steve-B Posted August 3, 2003 Share Posted August 3, 2003 V7, i'm of the opinion that we don't have enough airflow on our engines no matter what we do to keep the temps near the thermostat rating. i consider that it's just the way the K is. other engines seem to track better with temps & thermostats that the K. i don't loose sleep over it. i am mindful of it though Steve B Faster than the Speed of Dark Join us on the USA 2005 tour......HERE Link to comment Share on other sites More sharing options...
Bricol Posted August 3, 2003 Share Posted August 3, 2003 I was running a standard 1600 K with the exception of an apollo - temp never moved off an indicated 80 for the 2 weeks. Apart from: 1) Sitting at the top of passes waiting for poorly running 21s to catch up when it crept up a touch to 85 ish 2) On the autostrada one day it dropped to 40 ?!? Its the 3rd new sender in 2 yrs so I guess it was a sender glitch - was back to 80 soon enough. Bri Link to comment Share on other sites More sharing options...
V7 SLR Posted August 3, 2003 Author Share Posted August 3, 2003 Quite a few others observed similar results to you Brian which is why it's doubly irritating to me as I have a "technically" superior radiator. Steve Wiseman noted that the fins on my rad look a little tired which would probably affect airflow through it, particularly at low speeds and situations where the airflow is only as a consequence of the fan. The other difference is the laminova. Perhaps my radiator isn't such an overkill solution as I previously thought and can't cope with the dumping of heat from the oil system into the cooling system... however most of the time the oil was below the temp of the coolant anyway so it would have actually been helping to bring the coolant temp down. I'm perplexed by this, and the fact that the thermostat doesn't keep the engine temp up when driving in the cold. Maybe it's knackered and I need to buy another. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Steve-B Posted August 3, 2003 Share Posted August 3, 2003 V7 since i converted to your suggested lower temp thermo my engine is quite cool in winter, and stable warmth in summer. i think we're on the right track here, and suggest that other than sitting with a blade straightening your fins, that there's nothing more that can be done. my thermo as you know is only about 4 months old. Steve B Faster than the Speed of Dark Join us on the USA 2005 tour......HERE Link to comment Share on other sites More sharing options...
V7 SLR Posted August 3, 2003 Author Share Posted August 3, 2003 Yeah but the point is that the thermostat should keep the engine temp up to the rated temp in cool ambient temps by partially or fully closing and yet you have described exactly the same observation as I have noted. Low temps are only one of the two issues I've got. To cool mine better I really am going to have a go at straightening my fins. They're not that bad. Perhaps a blast through with a pressure jet will clean it and improve the situation too..?? Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Bare Posted August 3, 2003 Share Posted August 3, 2003 Dunno if this is relevant .. but in my experiences Thermostats.. (like all other parts:-) are not of equal quality. Perhaps taking the thing out and heating it in a pot with a thermometer might reveal a problem.. if any. Link to comment Share on other sites More sharing options...
V7 SLR Posted August 3, 2003 Author Share Posted August 3, 2003 Good point. If I can establish at which point the thermostat starts to open and when it is fully open I ought to be better able to correlate my observations with what's happening. To be properly accurate I ought to use the Spa gauges and their sender whilst boiling my thermostat too. I'll report back when I've done it. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Paul Ranson Posted August 3, 2003 Share Posted August 3, 2003 How 'fast' are the SPA sensors? This afternoon I've been sitting in the passenger seat of a car fitted with a mildly modified K in a very non-standard installation, using a laptop showing the real time data from the ECU to monitor the coolant temperature. When just driving the thermostat seems to be set at about 88. The temperature rises to 88 or 89 and then falls rapidly to 77ish and then starts to rise again. As time goes by the swing is reduced. If the engine is allowed to idle then the temperature rises to 90ish when the fan comes on. In this mode the thermostat is presumably permanently open and the fan switch becomes the control. Anyway everything we saw made sense. Which was confidence inducing given that the temperature gauge on the panel hung about between 70 and 80.... So it may be worth doing something similar, looking at the instantaneous temperature. And getting a second opinion in the passenger seat while you exercise the engine may also help work out what's going on. Paul Link to comment Share on other sites More sharing options...
V7 SLR Posted August 3, 2003 Author Share Posted August 3, 2003 The Spa gauges appear to register as quickly as the ECU registers its data. There is a small offset of a degree but nothing terribly serious. The are two questions. The first is that although I've got a 76 degree thermostat (reputedly), the engine can run colder. That's not right so I need to test the thermostat to see if it really is a 76 degree jobbie. Then there's the belief that I have an over-capacity radiator so I was alarmed when my temperatures rose into the 90's. Perhaps that is the limit of my radiator capacity and early 90's isn't too bad... but I'd rather have seen temperature no higher than early/mid 80's. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Paul Ranson Posted August 3, 2003 Share Posted August 3, 2003 When you're in the radiator fan zone your running temperature will be defined by the switch on the fan (or by the setting in the ECU). This afternoon we had between 85 and 90 at idle, solely controlled by the fan and the hysteresis in the fan thermostat. So driving about when the radiator is being cooled by the air and the thermostat is opening and closing we saw 76-88, when idling and in equilbrium the thermostat is wide open and the temperature is controlled by the fan at 86-92. I don't know where the temp sensors on your car are, or their relationship to the thermostat, but a combination of layout and tolerance could explain your symptoms. The key is that you don't overheat.... Paul Link to comment Share on other sites More sharing options...
Bricol Posted August 3, 2003 Share Posted August 3, 2003 Even towing a damn great 21 up the highest pass in Europe didn't get my temps above an indicated 80! No idea of oil temp - I have a sender fitted, a wire connected but not at the guage end so . . . I did straighten some fins out on my rad before Italy and gave it a blow through with compressed air (gentler than a pressure washer) - which I did again today to remove all sorts of interesting looking insects! The cooling fan did seem to be on most of the time which did concern me a little as it shouldn't really according to theory - but as temps stayed constant an okay I worried less as the tour went on. The easiest thing here would seem to be to try another stat. On a direct copy of the tour . . . I'm free in about a week . . . anyone else . . .? Bri Link to comment Share on other sites More sharing options...
V7 SLR Posted August 3, 2003 Author Share Posted August 3, 2003 Post that last line on the Tour7 list and see how much response you get. I'll bet you get 90% of the drivers and 0% of the passengers. 😬 Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted August 4, 2003 Support Team Share Posted August 4, 2003 V7, I am trying to get to grips with temperatures myself and have a couple of thoughts: 1. Although your thermostat is nominally 76 degrees, that could be fully open so at 69 degrees it could be partially open allowing enough coolant to flow through the radiator to be cooled down to 69 hence your "mountain" temperature. If the thermostat is faulty or not particularly accurate then this could definitely be the cause. 2. The higher temperatures are not necessarily indicative of an undercapacity cooling system as the efficiency of any heat exchanger is dependent on the temperature differential across it. Therefore the radiator is not dumping heat fast enough until it has reached a certain temperature - perhaps in your case around 90 degrees. Your temperatures don't seem excessive (my fan doesn't come on until 100 degrees ) and you don't want to run too cool either. In Le Mans I was regularly getting around 105 degrees when stuck in traffic and my new radiator should reduce that. Assuming your radiator is up to the job (which I think it is) perhaps you should stick with the Laminova. As Steve said, airflow is the biggest problem on the 7 so where would you site a separate oil cooler? If you put it in front of the radiator then it will reduce the cooling effect of the radiator. Shaun Yellow SL #32 Link to comment Share on other sites More sharing options...
I.Mupferit Posted August 4, 2003 Share Posted August 4, 2003 An interesting thread and, obviously, very relevant at the moment. I found, during a recent trip to Bordeaux in temperatures up to 42 C that the standard rad coped most times apart from in heavy traffic. The fan would cut in at about 100 C but would only hold the temperature at that level until moving again ie, it didn't reduce the temperature as I had expected. I have just fitted a new Ali radiator which I am hoping will dump sufficient heat for the fan to actually reduce the temperature whilst stationary but if that is un-successful, I am looking at the possibility of fitting a larger fan to move a much higher volume of air. The existing fan is quite puny and 9" diameter but it looks possible to fit an 11" diameter high throughput fan which should solve all overheating problems whilst moving slowly or stationary in warmer climes. Brent Link to comment Share on other sites More sharing options...
V7 SLR Posted August 4, 2003 Author Share Posted August 4, 2003 I suppose my concerns with regards to the high temps observed were that other people, Bricol included, witnessed much lower temps in their cars despite their having technically inferior radiators. It could be that my gauges are the only ones displaying true temperature and that theirs are widly inaccurate. Nothing new if they're Caterham gauges. Bit worrying if not though. Perhaps also, the fact that I've got a DVA'd VHPD means I'm creating more heat? Possible? I'd have thought so, but I'd have though the difference would be minimal. I accept that the under temps achieved may be nothing more than an inaccurate thermostat. Judging by the technology involved in a thermostat, I would say that this is a likely reason for my under temps. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
Support Team Shaun_E Posted August 4, 2003 Support Team Share Posted August 4, 2003 V7 - I suspect you are right about your gauges. I am running a Stack dash so am confident that my indicated temperatures are reasonably accurate. Brent - I fitted my Radtec over the weekend and when the (standard) fan cuts in at around 100 degrees the temperature begins to drop quite quickly and within a minute or so is below 95 - I only tried this stationary on the drive but that should reflect sitting in traffic. As soon as you move, the airflow is enough to drop the temperature even more quickly and on a hard blat I didn't see more than 87 degrees. I'm very pleased with it. Shaun Yellow SL #32 Link to comment Share on other sites More sharing options...
Paul Ranson Posted August 4, 2003 Share Posted August 4, 2003 Nigel, your high temperatures in traffic are nothing to do with the radiator or thermostat and everything to do with the fan and its switch. But from your reported readings the traffic high is fine. So don't worry about it. Paul Link to comment Share on other sites More sharing options...
V7 SLR Posted August 4, 2003 Author Share Posted August 4, 2003 Paul... you're right of course. Hadn't thought about it that way. I was "stuck" on the idea that others hadn't reported such high temps and it forced a little bee into my head. Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours Link to comment Share on other sites More sharing options...
kodiak Posted August 16, 2003 Share Posted August 16, 2003 ive been having the same sort of issues on track this year. (running a roadsport A in the eurocup) early in the year, had a nasty experience - engine overheated (reasons not exactly clear) , it dumped the coolant - which led to an expensive trip to ministers... after that ive been almost paranoid about the temp (not wanting a repeat) ... 2 improvements have been made - a) put on manual switch on the fan (in addition to auto cut in) , minister told me the engine performances starts to deteriorate before the fan kicks in anyway b) put a triple pass rad (in place of the std ali one) does seem to have improved things, but still - mid race its getting up in the high 90s, whilst other same spec cars are only hitting mid 80s ive been told its ok as long as its not hitting a 100 - thoughts? another strange one - another car, which was reporting similar temps - seems to have had a stack temp sensor misreading (by about 15 deg)... do this often go wrong? could my problem with overheating have damaged my sensor too? Link to comment Share on other sites More sharing options...
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