Pete Lewis Posted October 6 Report Share Posted October 6 a blocked rad core tubes will gain heat under speed /power is being generated quicker than you can disperse it. then a blowing head gasket will give more gas and heating Pete Link to comment Share on other sites More sharing options...
JohnD Posted October 6 Report Share Posted October 6 1 minute ago, Pete Lewis said: a blocked rad core tubes will gain heat under speed Pete Pete, I beg to differ! A blocked tube will have no hot water running through it, but will have normal air flow around it. So that tube will be COOLER than the rest of the rad. This allows testing, either with the hand or an IR gun. If dirt in the rad blocks air flow, but the tube is clear, then the opposite is true and that part of the rad will get HOTTER! John Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 6 Report Share Posted October 6 the aerodynamics of the vitesse resembles a brick i dont see air ram at speed being a flow problem Pete Link to comment Share on other sites More sharing options...
johny Posted October 6 Report Share Posted October 6 1 hour ago, James H said: Hang on so... ...on a standard well tuned engine with a working water pump its the fan/rad combo that dictates cooling effectiveness at idle so if thats a non issue and the car doesn't overheat regardless of ambient air temp/weather/climate what could then potentially produce overheating issues at speed under load other than a flock of birds embedded in the grill ? Is it feasible that at idle the fan does most of the job with the rad design being less significant, whereas while under load the rad design becomes the more critical for general airflow ? This again would suggest that a "solid" rad while very effective for the coolant system would also restrict airflow directly to the compartment / bloc which on a modern car maybe isn't an issue but on a hot running 6 maybe it is ? Ive got a bit lost here but yes a poor rad + good fan = ok at idle, good rad + no fan = ok at speed. If by "solid" rad you mean one fitted with a shroud yes air flow through it and so into the engine bay at speed could be reduced a little but engine bay temperature at speed doesnt seem to be a problem in our cars. However it can be a problem at slow speeds and of course there an efficient fan does help... Going back to your first point there have been problems reported of cooling at speed due to frontal airflow issues with solutions on different models involving number plate repositioning, air scoop installation and boxing in of the radiator entry area. Link to comment Share on other sites More sharing options...
James H Posted October 6 Author Report Share Posted October 6 (edited) 19 hours ago, johny said: If by "solid" rad you mean one fitted with a shroud Hi, no sorry by "solid" I meant like the alu one you have since they appear to have reduced airflow, I'm obviously missing something... I was under the impression the volume of under bonnet airflow was dictated by a rad but you say "engine bay temperature at speed doesnt seem to be a problem in our cars" so fair enough 👍 Edited October 7 by James H Link to comment Share on other sites More sharing options...
James H Posted October 6 Author Report Share Posted October 6 9 minutes ago, johny said: Going back to your first point there have been problems reported of cooling at speed due to frontal airflow issues with solutions on different models involving number plate repositioning, air scoop installation and boxing in of the radiator entry area. Thats what I thought, what else could it be, an easy fix then ! Link to comment Share on other sites More sharing options...
johny Posted October 6 Report Share Posted October 6 4 minutes ago, James H said: Hi, no sorry by "solid" I meant like the alu one you have since they appear to have reduced airflow, I'm obviously missing something... I was under the impression the volume of under bonnet airflow was dictated by a rad but you say "engine bay temperature at speed doesnt seem to be a problem in our cars" so fair enough 👍 Nothing solid about the aluminium radiators. They have the tubes closer together than Triumph originals and fins more densely packed but aluminium being stronger than copper means it can made thinner so good air flow is still maintained. Then its all brazed together which is better for heat transfer than the soldering used in copper rads so although ali not as good a thermal conductor the end result should be better (certainly cheaper and lighter)... Link to comment Share on other sites More sharing options...
johny Posted October 6 Report Share Posted October 6 10 minutes ago, James H said: Thats what I thought, what else could it be, an easy fix then ! Well I think a poor condition radiator (fins missing, tubes blocked and dirty) can potentially have more effect on driving cooling rather than at idle as the latter can masked to a certain extent by an efficient fan... Link to comment Share on other sites More sharing options...
James H Posted October 6 Author Report Share Posted October 6 (edited) On 06/10/2024 at 20:56, johny said: Nothing solid about the aluminium radiators. They have the tubes closer together than Triumph originals and fins more densely packed but aluminium being stronger than copper means it can made thinner so good air flow is still maintained. Then its all brazed together which is better for heat transfer than the soldering used in copper rads so although ali not as good a thermal conductor the end result should be better (certainly cheaper and lighter)... Apologies for all the confusion caused, I was going by the photo John posted previously having only seen it on a small screen mistaking it for some new-fangled solid core tech hence me saying "what a great bit of kit", anyway it appears I'm way behind many of you but I learn fast... However my point remains about restricting the airflow, that a shroud would improve airflow at idle but restrict it at speed but again you say "engine bay temperature at speed doesnt seem to be a problem in our cars" so fair enough Thanks for your patience Johny, appreciate you getting me up to speed 👍 Edited October 8 by James H Link to comment Share on other sites More sharing options...
JohnD Posted October 6 Report Share Posted October 6 "engine bay temperature at speed doesnt seem to be a problem in our cars" Did I say that? Because i dont agree! So many people, especially GT6 owners, complainp about heat in the passenger compartment. They blame heat transfer from the exhaust pipe, and spend a lot on insulation of the gearbox cover. Unnecessary, as not true! The problem is that all IC engines are very inefficient! The best moderns barely achieve 50% of the fuel burnt as propulsion. The rest is noise and HEAT! All that heat must be thrown away through the radiator, producing an engine compartment full of hot air, that must escape via the underside of the car and the transmission tunnel. Plus some that gets through into the passenger compartment via the many holes in the bulkhead, whose grommets have rotted/fallen out. This is not a theory. I built a Vitesse with the radiator in the back. This was a racing experiment, not entirely successful, but the Silverback was a very cold car! All that excess heat disappeared out of the back, none in the front. Now, Sb's successor has a front rad, with extractor ducts on the bonnet to promote heat removal. John 1 Link to comment Share on other sites More sharing options...
johny Posted October 6 Report Share Posted October 6 yes John the heat might be a problem for occupants but I meant once driving I havent heard of high under bonnet temperatures on standard cars causing engine running issues like fuel vaporisation or component damage. The only exception might be some electronic ignition units failures we've heard of but usually theres enough air flow on the move from the radiator and elsewhere to prevent this... Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) 17 hours ago, JohnD said: They blame heat transfer from the exhaust pipe, and spend a lot on insulation of the gearbox cover. Unnecessary, as not true! I built a Vitesse with the radiator in the back. All that excess heat disappeared out of the back, none in the front. Morning, Naturally I too have always suspected the exhaust for any undesirable heat in the cabin on mine but it sounds very complicated to prove otherwise based on what you say "is not a theory"... In any case maybe in the light of day its become clear no-one quoted you as saying "engine bay temperature at speed doesn't seem to be a problem in our cars" Johny and I were also trying to keep it specific to "a standard well tuned engine". Could this be a simple case of too much ( or too little ) sunday evening alcohol 😉 Edited October 7 by James H Link to comment Share on other sites More sharing options...
JohnD Posted October 7 Report Share Posted October 7 14 hours ago, johny said: Ive got a bit lost here but yes a poor rad + good fan = ok at idle, good rad + no fan = ok at speed. If by "solid" rad you mean one fitted with a shroud yes air flow through it and so into the engine bay at speed could be reduced a little but engine bay temperature at speed doesnt seem to be a problem in our cars. However it can be a problem at slow speeds and of course there an efficient fan does help... Going back to your first point there have been problems reported of cooling at speed due to frontal airflow issues with solutions on different models involving number plate repositioning, air scoop installation and boxing in of the radiator entry area. I was quoting johnny, and pointing out the frequent complaints, especially from GT6 drivers, about cockpit heat in road cars. Anyway, I wasn't as thunk as you drunk I was. Link to comment Share on other sites More sharing options...
Iain T Posted October 7 Report Share Posted October 7 (edited) My cooling system with no belt driven fan only a 12 inch Spal copes well but I've noticed on inclines and driven enthusiastically the water temperature does rise until the system adjusts. As John said it's our inefficient IC engines. Not a problem unless the temperature keeps rising! I think the later cars ie my Mk2 Vitesse could benefit from a separate header. Iain Edited October 7 by Iain T Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) Johny you say "The gauge goes up and down with the most worrying being long hot mountain climbs" which if I've understood well would suggest the rad is the weak link, would it not ? John you say "The problem is that all IC engines are very inefficient! ... All that heat must be thrown away through the radiator, producing an engine compartment full of hot air, that must escape via the underside of the car and the transmission tunnel ... I built a Vitesse with the radiator in the back ... All that excess heat disappeared out of the back, none in the front." did that then require reducing airflow to the engine compartment to avoid it running too cold ? Its also just occurred to me that a mechanical or thermostatically controlled electric fan that works regardless when at speed/under load, although redundant for the coolant system would surely help circulate "an engine compartment full of hot air"... Johny I'm fine with the primary school teacher for adults approach and John I'm fine with the university professor for toddlers approach, just want to keep learning 👍 Edited October 8 by James H Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) 1 hour ago, Iain T said: My cooling system with no belt driven fan only a 12 inch Spal copes well but I've noticed on inclines and driven enthusiastically the water temperature does rise until the system adjusts. As John said it's our inefficient IC engines. Not a problem unless the temperature keeps rising! I think the later cars ie my Mk2 Vitesse could benefit from a separate header. Iain Iain hi, I'm trying to gain a solid understanding of this so if you're ok at idle but it only rises when "on inclines and driven enthusiastically" would that not again suggest the rad is the weak link ? Edited October 7 by James H Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) Since I'm running a stock(ish) rad and it also only rises under said conditions is it that we're simply at the limit of technology for maintaining temps under all conditions on our cars with inherently "inefficient IC engines" ?? It would also suggest that stock(ish) is actually more than adequate, that for people with serious overheating issues the problem almost certainly lies elsewhere (blockages/restrictions/component failure etc) and that upgrades are for the tinkerers ! If it is indeed a fair conclusion to make I think its important to say if it will save those with real overheating issues unnecessarily barking up the wrong and often very expensive tree Edited October 7 by James H Link to comment Share on other sites More sharing options...
johny Posted October 7 Report Share Posted October 7 2 hours ago, James H said: Johny you say "The gauge goes up and down with the most worrying being long hot mountain climbs" which if I've understood well would suggest the rad is the weak link, would it not ? Well I think the gauge going up and down is totally normal especially if your thermostat is fully open and no longer able to control the coolant temperature. As I explained earlier its self regulating, as coolant temperature rises more heat energy is transferred to the atmosphere and a new point of equilibrium is reached. However just to throw something else into the conundrum, its widely believed that modern cars have their temperature gauges (if one is even supplied) electronically stabilised so that the driver no longer sees these variations and consequently doesnt stress over a rising needle.... Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) 15 minutes ago, johny said: its widely believed that modern cars have their temperature gauges (if one is even supplied) electronically stabilised so that the driver no longer sees these variations and consequently doesnt stress over a rising needle.... Is it fair to say then we're in agreement that "we're simply at the limit of technology for maintaining temps under all conditions on our cars with inherently "inefficient IC engines"" ? As Iain said its not an issue if they don't overheat but it is important not to let people think money can buy a solution to a problem that doesn't exist... to be clear I'm not a purist and don't judge those who want to experiment either but for those just looking for answers to a real overheating problem some clarity would be beneficial Edited October 7 by James H Link to comment Share on other sites More sharing options...
Pete Lewis Posted October 7 Report Share Posted October 7 and dont discount charging up hill in 3rd give it some beans and your charge rate could well increase if the stabilised voltage is not as stabilised as it should be then the gauge starts to read out higher temperatures bi metal gauges and the inherant hic ups they can have even got guys changing engines due to the reading on these old gauges, due to paranoid gauge watching, yes they changed the engine , got the same problem then swapped the sender unit pity its all on the lost forum made me smile Pete Link to comment Share on other sites More sharing options...
Iain T Posted October 7 Report Share Posted October 7 (edited) 2 hours ago, James H said: Iain hi, I'm trying to gain a solid understanding of this so if you're ok at idle but it only rises when "on inclines and driven enthusiastically" would that not again suggest the rad is the weak link ? +1 for Johny's explanation. It's just a game of catch up and the system is operating normally. It when the coolant temperature gets too hot that there could be an issue with the system or as Pete says just electrical gremlins rattling the worry beads...! Iain Edited October 7 by Iain T Link to comment Share on other sites More sharing options...
johny Posted October 7 Report Share Posted October 7 All only theories and stuff picked up along the way Im afraid so wont stand up in court🥸 Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) Come on chaps, throw me a bone here, I'd appreciate your weighted opinions even if they wont stand up in court... Anyway my conclusion is that for someone who has an overheating issue on a standard car, either at idle or at speed, upgrading the fan/rad/stat/header isn't the way to go* because stock cars have been proven to cope in extreme climates, instead the problem almost certainly lies elsewhere such as blockages/restrictions/component failure or tuning... * they might help but only by masking the real underlying issue/s Edited October 7 by James H Link to comment Share on other sites More sharing options...
johny Posted October 7 Report Share Posted October 7 I think if you have cooling problems its just a case of working though the list of possible causes. Ensuring engine is running efficiently, cooling system as clean as possible and radiator in good condition. Then if still an issue move on to upgrades and mods... Its just possible that there are physical differences between engines such as the casting of internal cooling passages etc (back in those days the manufacturing processes were a lot less tightly controlled) which might account for differences in cooling. With this in mind Ive even filled in behind my water pump with epoxy resin to make sure the gap between the casing and impellor is as tight as possible to maximise coolant flow but unfortunately cant prove any improvement😀 Link to comment Share on other sites More sharing options...
James H Posted October 7 Author Report Share Posted October 7 (edited) 19 hours ago, johny said: Its just possible that there are physical differences between engines such as the casting of internal cooling passages etc (back in those days the manufacturing processes were a lot less tightly controlled) which might account for differences in cooling. That crossed my mind too but maybe its a bit of a long shot... My car has a non original engine and has frankly been botched together by the po, yes I have done alot to it myself but I don't claim to perform miracles and have a fraction of the competence of many of you yet it performs as good as can be expected. Edited October 8 by James H Link to comment Share on other sites More sharing options...
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