MogLite Posted September 29, 2006 Share Posted September 29, 2006 Well it isn't much of a system TBH As a reminder Transit radiator - rear mounted 2 x Cosworth fans - sucking X-eng 2-setting switch in the bottom rad hose tee from bottom rad hose to standard expansion tank No heater or associated hoses VDO sender in stock position on V8 intake manifold VDO gauge matched to sender Yes I know the rad could be considered a little on the small side Yes I know adding more water to the system by plumbing in a heater/2nd rad would help But before I re-design I'd like to make sense of what I've got. Whilst shaking down at Seven Sisters I was seeing a running temp of approx 100C - which in September is a little hot for my liking. When it went to 105 - the second fan would kick in from the x-eng switch I though 105 was too warm for the 2nd fan to be kicking in, and I'd like it to run much cooler than that. Fridge asked a pertinent question > Where is your fan switch fitted relative to your temp gauge sender? > Remember those switches have a 5-15deg hysteresis between off and > on so > it's not going to switch at exactly the same temp. > J _ Hysteresis - good word :-) The temperature sender is in the stock position in the V8 intake manifold - its VDO to match the gauge. The fan switch is an X-eng jobbie in the bottom radiator hose. I'm assuming that the water flow is pumped "out of the top of the water pump" into the top of the rad Out of the bottom of the rad Past the x-eng fan switch Back into the block Assuming the gauge and fan switch are accurate. The 2nd fan comes on at about 105C Yet the X-eng switch switches the fan on at 92C (13 degree difference across the rad with one fan on) I'm thinking it doesn't matter what temp the water comes out of the block (within reason) it's the temp that it goes back into the block - ie to show the rad is doing its job ? So I could re-position the temp gauge sender to the bottom of the rad pipe ? Or I could stop panicing about 105-110C on the temperature gauge because I know its in the wrong place and it is therefore reading at least 13degrees high (possibly more with the 2nd fan kicked in) True ? Quote Link to comment Share on other sites More sharing options...
02GF74 Posted September 29, 2006 Share Posted September 29, 2006 first thing I should have said is have you measure the water temperature accurately? I'm assuming that the water flow is pumped "out of the top of the water pump" into the top of the rad I'm pretty sure water goes into rad from themostat housing; water pump therfore has to suck water from lower rad tube back into the block. (ah, I say top/bottom as in a series rad with top to bottom flow; modern rads have side to side flow) yeah, I'll study the rest and comment but 105 is too high. righty ho. if I'm right about the water pump flow, then I beleive the water goes into the block at the front behind the pump, along the cylinder liners to the back of the block then up into the heads and finally into the inlet manifold where it exits. your temp sender is measuring water after it has been heated; typically you are aiming at 90. the thermostat is controlling water flow out of the engine; once the water temp is too high, it opens in the hope that cooler water can flow into the engine. now raidator & fans. under normal driving conditions - air is forced by virtue of forward motion to cool the water and size of radiator is matched so that this happens at reasonable roads speeds. For times when you go slower than that, you have fans to draw air trhough the radiator. yours being in the back mean you get significantly less cooling by forced air hence you have the fans. you have the engine in front of the radiator so first thing you should look at is having a path of air that is not warmed up by the engine entering your radiator. the temp controller's position, I don't see that is makes much difference whether it is at entry of exit to radiator; it is the thermostat that will have greater control as it will stop water flow if rdaitor os overcooling (you wish!) and remain open when not cool enough - but I need to think about this a bit more. I did work out the water flow some tiem ago = maybe someone can find the post - and seem to recall that the radiator volume gets flushed about 3 or 4 times per second so theere is not that much delay between the water entering and exiting - hence why I say switch position does not matter that much. oh before I forget, someone mentioned heater; I don't think that is going to make that much difference; you increase the size of the heat sink but that buy you a bit of time - you really chould be concentrating at getting heat from the water to air. I have some suggestions as to what you should do but tell me so when both were running, did one or both ever stop running? Quote Link to comment Share on other sites More sharing options...
will_warne Posted September 29, 2006 Share Posted September 29, 2006 Andy, I'd try and see what happens if you move the x-eng switch up onto the top pipe where everything's warmer. That way the fans come on sooner and you should run cooler. I think you want to worry about the max temperature inside the engine as that's what's going to do the damage. I don't think there's anything wrong with the rad itself; it was chucking out a hell of a lot of heat and I don't think your going to run into mud ingress problems where it is! Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 I like thermostats halfway down the rad - works for the car manufacturers nice bloke in Reading will put a thermostat boss on your rad for about £15 Andy, might be worth a whirl? I can pick it up on "Laugh at Al" day and drop it up to him if you like? Quote Link to comment Share on other sites More sharing options...
MogLite Posted September 29, 2006 Author Share Posted September 29, 2006 Andy, I'd try and see what happens if you move the x-eng switch up onto the top pipe where everything's From Simon's fitting instructions "The adaptor should be fitted in the bottom radiator hose. The water flows in to the top of the radiator and out of the bottom so the sensor will detect when the radiator is not providing enough cooling itself and switch on one or both fans to provide more" So I think its more of a case of where I measure the temp - not where the x-thing is. Dunno why the factory put the sensor where it is, but as there is no calibtration on the stock one - its only a swingometer - I guess it didn't matter to them. 02 - yeah thats how I imagined the water flow. Quote Link to comment Share on other sites More sharing options...
jules Posted September 29, 2006 Share Posted September 29, 2006 I may be missing the piont but a 8 normaly has about 10-12lt of water going round its system does the transit rad give you that much capasity.. remember I race a car which only has 3lt water in its rad Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 if you are measuring temp in the stock position then you need to be hitting whats considered a normal value on the guage for that engine? if theres ambiguity about the guage and sender then swap in a stock rangie setup to test it? sounds more like insufficient fluid capacity or radiator inefficiency - swap for a thinner alloy cored rad? or........ only drive in winter? it was warm that weekend though Andy and you dont have any airflow through your rad so its fans or nothing, ducting possible? Quote Link to comment Share on other sites More sharing options...
02GF74 Posted September 29, 2006 Share Posted September 29, 2006 some data that may be of interest; doesn't say how many cores. make/model cc len height Ford mk5 transist 2.5 D 600 322 mk3 2. 2.5 D 600 302 range rover 70 -> 3.5 l 694 366 85-98 3.5 740 420 Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 that makes the tranny about 60% lower in volume than a 3.5 rad, assuming 3 cores each booster rad up front? Quote Link to comment Share on other sites More sharing options...
jules Posted September 29, 2006 Share Posted September 29, 2006 that makes the tranny about 60% lower in volume than a 3.5 rad, assuming 3 cores each booster rad up front? May be a big heater under the seats which takes about 6 lt then Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 plumb it into Andys blanket Jules? - old people like warmth.. Quote Link to comment Share on other sites More sharing options...
jules Posted September 29, 2006 Share Posted September 29, 2006 plumb it into Andys blanket Jules? - old people like warmth.. Quote Link to comment Share on other sites More sharing options...
MogLite Posted September 29, 2006 Author Share Posted September 29, 2006 I like thermostats halfway down the rad - works for the car manufacturers nice bloke in Reading will put a thermostat boss on your rad for about £15 Andy, might be worth a whirl? I can pick it up on "Laugh at Al" day and drop it up to him if you like? Decent of you - but the Transit rad has plastic header tanks - so fitting a boss could be a bit smelly But its easy enough to rash a bsp fitting for a sender into the X-fan. 02 - "your temp sender is measuring water after it has been heated; typically you are aiming at 90" Sorry but where did you get that from. A powerful engine is going to generate lots of heat, as long as the radiator can stabalise the temperature, then I don't see how the output temperature is important. IYSWIM Ducting isn't the answer - MogLite is gonna spend a lot of its time at less than 5mph - so I want to rely on fans/design not ducting. Ensuring air that is drawn in is cool, is a fair point though. 02 "someone mentioned heater; I don't think that is going to make that much difference" You've never owned a Triumph Stag then have you - that was the saviour of their marginal cooling system !! Thank god they were soft-top or you'd sweat to death How often the first fan was on - I can't remember. The 2nd fan came on occasionally as people behind me could see it cut in/out. So the cooling system wasn't max'd all the time - which gives me some hope. The transit rad doesn't hold much water, but it looks to be quite an effiecient design. Off to pick up the kids from school - more later. Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 29, 2006 Share Posted September 29, 2006 Andy Hysterisis on most (if not all) of those switches is closer to 7 degrees average ………… never more then 10 or so. I have tried most positions (ooooer) and found the splice in the top hose to be the most reliable……. This point seems to be about 6degrees below actual engine temp. Like Jez noted, a lot of manufacturers place the switch between the top and halfway down the rad …… usually directly below the top hose entry point. For a slow moving vehicle off road 100c is OK …………. That equates to ¾ on a cold / norm / hot type gauge ……….. in other words it would be on the high side of normal. If I come down the M’way working the engine hard and cruising at 85/90 then mine will rise to 100c on the up hills, drop to 90 on the down hills and be at about 95c on the flat. At normal speeds it sits comfortably at 90c Off road whilst and working the vehicle ( slow climbs etc) then anything up to 100 will be the norm………. with the fans providing more than adequate cooling once the 100 has been reached. My fans cut in at 95c on slow speed …………… and change to high speed if the temperature gets to 100c. IIRC is you take into account the coolant @50% and the 15psi pressure, your boiling point will be 120 -125c. Ian Quote Link to comment Share on other sites More sharing options...
freeagent Posted September 29, 2006 Share Posted September 29, 2006 i might be wrong here, but at 100C water becomes a gas (steam) and its effectivness at removing heat becomes significantly diminished, as it isn't as dense as a liquid... so surely the ideal must be below 100C... at all times... Quote Link to comment Share on other sites More sharing options...
jules Posted September 29, 2006 Share Posted September 29, 2006 i might be wrong here, but at 100C water becomes a gas (steam) and its effectivness at removing heat becomes significantly diminished, as it isn't as dense as a liquid...so surely the ideal must be below 100C... at all times... no water under pressure will not boil untill it gets hotter and the 100c boiling point incresses read BBC bottom line of his post Quote Link to comment Share on other sites More sharing options...
bishbosh Posted September 29, 2006 Share Posted September 29, 2006 If you want the fans to cut in earlier then change the switch - Intermotor do literally hundreds of them with different on/off temperatures. Do a search on here for Intermotor or wait a few seconds for Ian to post up the list Quote Link to comment Share on other sites More sharing options...
Bull Bar Cowboy Posted September 29, 2006 Share Posted September 29, 2006 i might be wrong here, but at 100C water becomes a gas (steam) and its effectivness at removing heat becomes significantly diminished, as it isn't as dense as a liquid...so surely the ideal must be below 100C... at all times... Whilst you may be right ……………. It is not water, but a 50 / 50 mix of coolant and water ……… also the system is pressurised to 15psi ……… water boiling point is increased under pressure and 15 psi brings it up close to 118.9c .................. Here is yor list of 22mm switches Andy .............. taken from the BBC libary of useless information Part number/spanner size/ thread/temp on/off 50100 29 M22 x 1.5 82-68 50101 29 M22 x 1.5 84-79/88-83 50250 29 M22 x 1.5 86-76 50012 29 M22 x 1.5 86-77 50090 29 M22 x 1.5 86-81 50120 29 M22 x 1.5 88-79 50295 29 M22 x 1.5 88-79 50296 29 M22 x 1.5 88-79/110-102 50271 29 M22 x 1.5 88-83 50272 29 M22 x 1.5 88-83 50275 29 M22 x 1.5 88-83 50217 29 M22 x 1.5 88-83/92-87 50091 29 M22 x 1.5 88-83/92-87 50212 29 M22 x 1.5 88-83/92-87 50213 29 M22 x 1.5 88-83/92-87 50216 29 M22 x 1.5 88-83/92-87 50221 29 M22 x 1.5 88-83/92-87 50219 29 M22 x 1.5 88-83/92-97 50240 29 M22 x 1.5 90-80 50110 29 M22 x 1.5 92-82 50111 29 M22 x 1.5 92-82 50112 29 M22 x 1.5 92-82 50113 29 M22 x 1.5 92-82/95-80 50218 29 M22 x 1.5 92-82/97-92 50170 29 M22 x 1.5 92-87 50200 29 M22 x 1.5 92-87 50210 29 M22 x 1.5 92-87 50211 29 M22 x 1.5 92-87 50220 29 M22 x 1.5 92-87 50230 29 M22 x 1.5 92-87 50231 29 M22 x 1.5 92-87 50235 29 M22 x 1.5 92-87 50260 29 M22 x 1.5 92-87 50270 29 M22 x 1.5 92-87 50280 29 M22 x 1.5 92-87 50281 29 M22 x 1.5 92-87 50285 29 M22 x 1.5 92-87 50290 29 M22 x 1.5 92-87 50215 29 M22 x 1.5 92-87/97-92 50011 29 M22 x 1.5 93-88 50102 29 M22 x 1.5 93-88/97-92 50035 29 M22 x 1.5 95-85/102-92 50130 29 M22 x 1.5 95-86 50030 29 M22 x 1.5 95-90 50033 29 M22 x 1.5 95-90 50061 29 M22 x 1.5 95-90 50062 29 M22 x 1.5 95-90 50160 29 M22 x 1.5 95-90 50092 29 M22 x 1.5 95-90/100-95 50174 29 M22 x 1.5 95-90/100-95 50104 29 M22 x 1.5 97-92 50282 29 M22 x 1.5 97-92 50103 29 M22 x 1.5 97-92/101 -96 50214 29 M22 x 1.5 97-92/102-97 50190 29 M22 x 1.5 100-95 50195 29 M22 x 1.5 100-95 50196 29 M22 x 1.5 100-95 50197 29 M22 x 1.5 100-95 50198 29 M22 x 1.5 100-95/110-105 50000 29 M22 x 1.5 103-98 50013 29 M22 x 1.5 103-98 50014 29 M22 x 1.5 103-98 50191 29 M22 x 1.5 120-115 Ian Quote Link to comment Share on other sites More sharing options...
02GF74 Posted September 29, 2006 Share Posted September 29, 2006 02 - "your temp sender is measuring water after it has been heated; typically you are aiming at 90"Sorry but where did you get that from. A powerful engine is going to generate lots of heat, as long as the radiator can stabalise the temperature, then I don't see how the output temperature is important. IYSWIM Ducting isn't the answer - MogLite is gonna spend a lot of its time at less than 5mph - so I want to rely on fans/design not ducting. Ensuring air that is drawn in is cool, is a fair point though. 02 "someone mentioned heater; I don't think that is going to make that much difference" You've never owned a Triumph Stag then have you - that was the saviour of their marginal cooling system !! Thank god they were soft-top or you'd sweat to death How often the first fan was on - I can't remember. The 2nd fan came on occasionally as people behind me could see it cut in/out. So the cooling system wasn't max'd all the time - which gives me some hope. The transit rad doesn't hold much water, but it looks to be quite an effiecient design. buttocks - typed resply then kicked the power switch so much shjorter. 1. car engines designed to run at aroun 90 C; part clearance plus optimum performance; too cold and heat from combustion goes to heat up engine instead of gases so less power; also lose power if too hot. temp across engine varies, colder at bottom, hotter at top - so at what point you measure temp? water leaving engine is a good a place as any; thermostat is there to regulate engine temp. 2. re: heater - I assumed you would have no fan. 3. transit radiator; efficincy of moving heat from water depends on a lot thing; construction: cores/fins/ease of air flow etc. so just by looking at a radiator, and unless you know all the parameters I don't see how you can say that - my reasoning is that car manufacturere know more about this than I do so it is a safe bet that if you use the radiator for the engine it was desingedfor, you won;t be far wrong i.e. use a RR for a RR as oppose toa diesel (which as people have posted on the forum tend to run cooler than petrol) for a RR engine. as both fans aren't running all the time nor are you loosing water/boiling over, you aren't far oof the mark. as thingy said, you would expect the temp to be higher in your application, but what would be a good number???? BTW you can fitr a smaller diameter pulley (i have on mine) to increase water flow . Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 if its not a new Rad then Rad bloke can flow test it for you. I'd go for wiring both fans to come on at the lower threshold as opposed to one at lower and the second chiming in at the higher value, you dont have airflow to help out a single fan so why bother running it on its own? flat out baby B) Quote Link to comment Share on other sites More sharing options...
will_warne Posted September 29, 2006 Share Posted September 29, 2006 O2, you'd be very suprised how much differnace the heater makes! Many a time I've had to put it on while driving back from events in the summer. Andy, have you also tried water wetter or simerlar? That might help take the edge off things.... Quote Link to comment Share on other sites More sharing options...
LR90 Posted September 29, 2006 Share Posted September 29, 2006 Andy, I'm not sure what you have if far of the mark. If the second fan is only cutting in from time to time that's a lost better than all or never. Using the lower hose to switch the fans has a lot of merit. You are stablising the return temp ot the water to the engine (though nearer to 90 max might be prefferable) and in the event of loss of pressure or air lock it is going to be pretty desperate by the time the lower sender is not imersessed in liquid. If you can keep this return temp down to an acceptable level then you don't need a larger rad/fans/volume. Quote Link to comment Share on other sites More sharing options...
MogLite Posted September 29, 2006 Author Share Posted September 29, 2006 I'm only running pure water at the moment. Nothing worse than seeing anti-freeze and water wetter p155 out of a leak Water wetter for a tenner will probably get added I'll move the sender for the gauge to the lower hose, at least that way the readings will be in the middle of the gauge which will lull me into a false security I'll add warning lights so I can see when each fan is on I'm scouring eBay for m'cycle rads and fans that I can add easily. I'll re-read some of the tech when I've got a clearer head Quote Link to comment Share on other sites More sharing options...
Andy Posted September 29, 2006 Share Posted September 29, 2006 i'd prefer the fan switches in the top hose tbh. my theory goes that the fans exist to control the water temp in the rad (getting it cold enough to return to the engine) so measure the temp going into the rad. with the switches in the bottom hose you need the water to be at 'switch temp' + 'cooling effect of the rad' before the fans come on. putting the switches in the top hose would regulate the water temp just as well in my opinion but would result in a cooler temp of water returning to the engine. Quote Link to comment Share on other sites More sharing options...
dollythelw Posted September 29, 2006 Share Posted September 29, 2006 adding antifreeze makes the cooling system more efficient so thats gotta help Pan European ST1100 Rad - nice size, might even have a spare in the garage if you get stuck? Quote Link to comment Share on other sites More sharing options...
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