hi folks, assuming my gauge is accurate, what is the normal running temperature of a 5a? Some kind soul in the past has re-wired the fan to a dash switch, bypassing the rad switch. Any suggestions as to when I should turn it on? ta Ade ------------------------------------------------------------------------- Ade, When you start the car cold and watch the temp guage, you will find that the temperature will rise quite quickly (ho ho, I mean over the a few minutes) until the thermostat opens - whereupon the temperature change will be quite minimal for some time as all that cold water from the radiator circulates round the system. This is the tempearture that the system should maintain and only when the radiator is too hot from the lack of air passing through it will the temperature start to rise again. This tends to be around 90degrees or so but can depend upon the temperature of the thermostat. I have been playing with a system to get rid of the switch you speak of as my radiator has no hole for an otter switch and I have finallised on www.geocities.com/nclnoggin/tech/thermal.htm using a big-ish relay from a thermal controller. I have noticed controllers such as this going for around œ15 ish from RS components www.rswww.com who will sell to anyone at their trade counters but remember that you need one that is open circuit cold and adjustable to switch 'on' at a higher temperature - the opposite of a heater controller that comes on cold and switches off when hot. The sensing bulb - if it is not clear on the site is simply jammed against the top fins of the radiator - when the radiator cools - the fan switches off. Hope this helps, Kindest Rgards, Chris ------------------------------------------------------------------------- www.geocities.com/nclnoggin Adrian Im not sure what the normal running temperature is meant to be but the 'otter' switch is meant to start the fan at 80 deg so that would be the time to flick the switch. My 5a also had the otter switch disconnected with an internal switch fitted. If this is a concealed switch (like mine) i see no need to remove it but to re-connect the otter switch in parrallel so you have the best of both worlds. ------------------------------------------------------------------------- Chris The mod you mentioned sounds interesting, do you know of a part no. and would this sense the liquid or simply attach to the rad casing. Does this mean the otter switches are not that reliable or would an additional relay help? Darren GUT 843N ----- Original Message ----- From: "Adrian Griffiths" To: "Scimitar Yahoo" Sent: Sunday, May 06, 2001 11:13 PM Subject: [ReliantScimitar] temp ------------------------------------------------------------------------- Hi all Im sure the subject was hammered out a few months ago but for your info i was given a Bosch fan (Passat) of the exact diameter as a standard SE5a. These are intended for a cowel but the lugs can be linished off to accommodate the scimitars 'U' bracket. Darren GUT843N ------------------------------------------------------------------------- Darren, I have been looking for the part number myself but can't find it - I shall look tomorrow in the paper catalogue and post the part number, unless it's has expired as things do in RS. The sensor bulb on mine just presses on the fins at the very top of the rad, held there by the bracket that holds the fan. and I have never had an otter switch so I cant realy comment but my rad has no hole for an otter so that option is not realy available for me. ISTR the original otter switch is ok for the original fan (8Amp-ish) but the usual Citroen BX fan mod draws monster current especially on start up (more than 15A - and I belw a few fuses before I got the meter out) will seriously comprimise your otter switch - I used a standard 35 amp relay. I suppose I could have drilled a hole in one of the side tanks on the rad and fed the sensor bulb in there soldering up after but the couple of journeys I have done so far with the setup as is have been good with the fan clicking in after a minute at the traffic lights then being off when I next come to a stop. Regards, Chris ------------------------------------------------------------------------- Hi, If you have a manual fan, turn it on if the temp gauge hits 90, and don't turn it off until it noticably drops (but not much - it can't drag the gauge down much, even with an aftermarket fan). As a matter of interest, if you start playing around with various non-std ways to handle the fan, you'll find that; If you put a sensor on the top hose, then no matter how good your fan is, it'll probably take ages to trip off, once it's started, because of the inertia of the cooling system etc. Thats probably why Reliant put the famous otter switch in such a superficially daft place. Where it is, one "radiatorfull" of water gets cooled by the fan, the otter switch trips, then another lot of hot water appears, and so on. This means it cycles quite often when at idle, and the water flow is low. If you fit an aftermarket/BX or whatever fan, you certainly need a relay, and a direct feed from the battery (fused, hopefully...), because most more modern fans take over 15A, my own fan takes 25A on startup. BR D. ------------------------------------------------------------------------- Chris Darren The latest Otter switches (available from Graham Walker) are extremely reliable and have very low on/off differential. All Otter switches need a relay - the damage done by continually switching an inductive load shortens their life somewhat. As you say if a better fan/motor is fitted a relay is essential. The Otter switch fits into a 'plain' hole (no boss or threads) so it's easy to fit if you haven't got one. The latest switch comes with a reliable clip fitting. Tony ------------------------------------------------------------------------- Folks, Forgive if this message comes through again but for some reason 3 hours have passed without my posting coming back (is this a record) All other comments taken but I don't feel the urge to drill a hole in my radiator despite it's age and especially as the new setup seems to work more or less the same as Dermot describes his. Here is the bluurb then and www.grocities.com/nclnoggins has it too under technical - thermal 0ø to +90ø 4øñ1ø 250-6106 œ13.74 0ø to +120ø 4øñ1ø 561-460 œ12.20 +40ø to +210ø 9øñ2ø 250-6083 œ14.70 +50ø to +300ø 10øñ2ø 250-6077 œ14.70 A search on www.rswww.com with say 561-460 will bring up a page of availables. I think I would probbers go for the 0 - 120 one with (I think) the 4 degree hysteresis, but the choice is yours. Looking at the length of the capiliary you could even have the control in the cockpit but - there again the ultimate is to have spark gap and timing chain adjusters - adjustable from the driving position - cough! All the best , Chris ------------------------------------------------------------------------- what do you mean Dermot, IF the temp reaches 90, 90 seems to be the general running temperature (according to the dial anyway)! What about running the fan when the car is moving? Is there any point (other than perhaps stop start city traffic)? I have only done a hundred or so miles (round town) since the MOT (tester must have been blind!) and temp has been pretty solid, apart from the other day, when I re-fitted the bottom radiator protection grill thing which was a previous owner's home made botch. The trip after that the temp went scarily high and I think I experienced fuel evaporation! it certainly wasn't happy. Anyway, new mesh in place seems to have settled that. Perhaps I will think about flushing the system out and fitting a meatier fan, although I wouldn;t have thought anything that came off a BX would be described as meaty! Ade ------------------------------------------------------------------------- Ade, If your car runs at 90 usually then that will be what the thermostat (waxstat) allows. Mine used to run at 90 but I changed it for a cooler waxstat and now it runs at less than that. The waxtat becomes the controlling element and temperature regulation occurs. Under normal stop start conditions the radiator temperatur rises and falls quite dramatically as heat is dumped into it from the engine by the waxstats attempts to maintain the engines temperature and usually you know nothing about this as the temperature sensor sees only the controlled temperature of the water in the inlet manifold. If the car is stopped (without fan) then the system overheats, the waxstat fully opens and the radiator has no cooling capacity left and can no longer regulate the water temperature then the water in the whole system including the inlet manifold where the sensor is, goes above the originally controlled level - 90 degrees in your case, and you see your guage rise. This is after when the fan is needed and usually this is predicted by an unusual rise in the radiator temperature, so operating the otter switch and cooling the radiator by fan. Sadly you, as the driver have no idea when this happens because all you have is the temperature guage on the inlet mainfold and you only find out about the impending over-heat when it has overheated. Solution, install an otter switch (and relay) or remember to switch on the fan when you predict an overheat, in traffic, on a hot day, after/during a long hill, As for meshes, I did some practical tests with fans and meshes at work and came to the startling conclusion that they can reduce air flow dramatically. It sounds like you have it sorted now but a fine mesh can be a real killer for airflow - as in half or quater. Flushing is always good and once a year springs to mind - not that I have done it but I did replace the original fan with a BX one and the overheat temperature actually does fall now as opposed to the original fan, where it just stopped rising. I hope never to know about this again now I have a radiator temperature switch installed. The BX fan is surprisingly monster and it is only after you have tried it on a battery whilst holding it in one hand do rude words flow and you count your fingers. *8-) Hmm, turned out quite long that Kindest Regards Chris ------------------------------------------------------------------------- Mike, I`ve got a `70 SE5 thats had the fan removed (its got the later engine) and I use a BX fan with a manual switch on the dashboard. Although you`ve got to keep you eye on the gauge in traffic the system works well and is simple. I just drop it in when it starts to rise a bit above 90. I`d advise anyone whos looking at fans off other cars to put on the scimitar, to take a good look at the camber of the blades. Quite a few are designed to pull air through, not push it as with the scimitar, and you don`t want the fan not to be working properly. Another thing with the SE5 is that if its got the original engine (128bhp) its going to produce less heat. This is one of the reasons why the crank driven fan works OK on se5`s. I`d be really interested to hear about your gas conversion. How are you getting the tank in? It`s something I`ve wanted to do for a while now but wasn`t really sure about downsizing or removing altogether the original tank. The price sounds good too! Cheers Nick. ------------------------------------------------------------------------- > Does anyone know - would it be worthwhile to remove the blades from the > mechanical fan to reduce drag, thus increasing horsepower, and to rig up an IIRC Kenlowe talk in the region of 2HP for a mechanical fan - that will be at high revs though I suspect so don't expect wadds more torque if you remove the blades. > Otter switch to control the electrical fan? I guess that this is probably > exactly what Reliant had in mind when they fitted electric fans as standard > to later models. > > Incidentally, I'm having a LPG conversion modification fitted tomorrow - > Wed 9 May 2001 at a cost of œ675. If anyone is interested in the results > just e-mail the group and I'll relate my experiences. Give me some time to > gather some new consumption figures though. I currently get ~23MPG on > unleaded. I don't use Leaded or Lead Replacement Petrol - a waste of money. > No abnormal engine wear either. I for one will be most interested, what are they fitting? single tank where the original fuel tank is, twin siamesed, doh-nut front? is it getting an ECU with Lambda sensor(s) new gas carb? I think that would be my choice - dump my worn webber and fit a gas carb. Sounds great, Scimitar driving with twice the economy - equivalent to 40-50 mpg?. I might even be able to afford to drive it ho ho .. Kindest Regards, Chris ------------------------------------------------------------------------- Mike, I`ve got a `70 SE5 thats had the fan removed (its got the later engine) and I use a BX fan with a manual switch on the dashboard. Although you`ve got to keep you eye on the gauge in traffic the system works well and is simple. I just drop it in when it starts to rise a bit above 90. I`d advise anyone whos looking at fans off other cars to put on the scimitar, to take a good look at the camber of the blades. Quite a few are designed to pull air through, not push it as with the scimitar, and you don`t want the fan not to be working properly. Another thing with the SE5 is that if its got the original engine (128bhp) its going to produce less heat. This is one of the reasons why the crank driven fan works OK on se5`s. I`d be really interested to hear about your gas conversion. How are you getting the tank in? It`s something I`ve wanted to do for a while now but wasn`t really sure about downsizing or removing altogether the original tank. The price sounds good too! Cheers Nick. ------------------------------------------------------------------------- thanks for the tips re fans etc, but pardon my ignorance what is an otter switch and what does it look like? Ade P.S. I'm interested in LPG too as I am pretty sure I need a new fuel tank which is going to be what, œ200, and if œ700 or so is the price for a boss LPG conversion job, then that is not SO much of a jump. Am I right that mile for mile you use more LPG than petrol, if so what is the estimated cruising distance on a tank, and indeed what is the capacity of the LPG tank? So who's going to tell the wife that we're not getting a new carpet for the lounge, but an LPG conversion for scimmy? Any offers ....... please.......I'm sure a small bunch of flowers will smooth things over.......(better be outside A&E when I tell her though, just in case!) Ade ------------------------------------------------------------------------- It's actually made by a company called Otter! But I prefer Peter's explanation. Another possibility is that it switches when the water gets Otter. Tony ------------------------------------------------------------------------- > It is the temerature sensing switch on the side of your radiator - drivers side on the edge, near the bottom - it switches your electric fan on and off. I assume the word OTTER comes from the animal which spend half of its time in the water and half out as the switch is half in and half out of the water. regards peter ------------------------------------------------------------------------- Chris, thanks for this - I'm just nearing MOT on my 5 rapid rebuild and was thinking about ways around controlling the BX fan I'd fitted in place of the mechanical one (as you say early cars didn't have otter switches because they only had mechanical fans) I didn't fancy drilling the rad and I wanted automatic switching with cabin override - the switch I'd rigged up under the bonnet for testing wasn't staying! I registered with RS and ordered tuesday night and it arrived today (thurs) - looks good - tested it - will hopefully fit it tomorrow. BR Jim ------------------------------------------------------------------------- Jim, Richard, folks Hope it works as well as mine does - at last, a project with a good outcome or at least one without blood, pain, hospitalisation, bankrupcy etc. I got my own web site url wrong below *sheesh* it of course is NOT nclnoggins but www.geocities.com/nclnoggin (without the s) and I have updated the text on the technical - thermal part to make it a little clearer where the sensor bulb is located. I may even try to take a photo of that too but it's a little tight and dark in there. Thanks for the steering info - Nottingham is North - but not quite North enough, perhaps I will have a look round for someone up here with tested alignment kit, but œ25 is still on the 'live with it' borderline as the problem is barely noticable. I do have a little question. People keep asking me 'why are they called noggins'. Apart from the obvious answer, does anyone know where the name comes from ? Kindest Regards, Chris ------------------------------------------------------------------------- To unsubscribe from this group, send an email to: ReliantScimitar-unsubscribe@yahoogroups.com Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/