| Gary M. | -- 06-11-2012 @ 5:41 PM |
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Is it possible to convert a 12v cooling fan to use on a 6v system so that it spins at the correct rpm`s . I already have the fan and would like to put it to use as an auxillary cooling source. Thanks....
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| supereal | -- 06-12-2012 @ 7:15 AM |
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The short answer is no. Electric fans draw high current, often thirty or more amps, so the usual voltage droppers can't handle the load. In any case, a relay is required, as most switches are too light.
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| joe b | -- 06-12-2012 @ 7:55 AM |
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Gary, I know you asked about converting but if you want to buy an electric cooling fan try Scott's Cooling Fans. They have a large selection of 6 volt fans and offer either pos or neg ground. scottscoolingfans@yahoo.com
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| Gary M. | -- 06-12-2012 @ 6:48 PM |
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If I do use the 12v fan with a 6v system it will only spin at half speed,which is still helpful in cooling. However,Im mot sure if this is damaging to the fan or the electrical system. Any ideas? Thanks...
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| fomocoloco | -- 06-15-2012 @ 5:03 AM |
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if in fact your fan spins at half speed, i would think that would greatly reduce the cooling, heat the fan up, and be in the way of the air flow. buy a 14" 6v fan. install it behind the radiator (pulling), and install a 6v, neg. ground, two wire alternator to power it. weezer
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| daoust | -- 06-15-2012 @ 12:48 PM |
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They certainly make 6V elerctric fans because I just un-installed one to get ready for concourse judging. David Daoust
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| Old Henry | -- 06-15-2012 @ 3:05 PM |
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If you have a 6 volt alternator you could probably run the 12 volt fan at half speed but a 6 volt generator will probably not be worth the effort, especially since the generator doesn't put out much below 30 mph anyway which is when you would benefit most by the fan. Bench test the fan hooked up to your 6 volt battery and see what you get on the battery alone. Then run it with the engine running and watch the amp gauge. If the amp gauge shows the battery discharging even at high RPM's you'll know the generator isn't carrying the load and isn't going to work. The fan motor won't be harmed by running on 1/2 voltage. If the generator puts out enough to charge the battery and run the fan at the same time it won't hurt the generator. You just may not get enough cooling assistance when you need it at low speed to be worth the effort. I know that in the winter when I'm driving at night with the brights on, the spot light on, the heater fan on full, and the radio on if I don't leave home with a fully charged battery the generator will not charge it up and eventually the battery is dead. That's how weak the 6 volt generators are. And that's a newly rebuilt one. I believe that's why we don't even have electric windshield wipers but just vacuum operated ones. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 6-15-12 @ 3:41 PM
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| Gary M. | -- 06-15-2012 @ 6:18 PM |
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The car has the original 6v pos grnd system,however,I have a 12v power inverter that runs only a modern radio and nothing else. I dont know how many amps the inverter puts out but i would think that it can handle the radio and the fan. I will check the specs on everything and see if its possible. Does anybody else run more than one item on a 12v inverter ? Thanks...
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| supereal | -- 06-15-2012 @ 6:45 PM |
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Most inverters can't produce the required current for electric fans. They usually demand 30 or more amps, more than most generators provide. If you go to an alternator, be sure it is a two wire type. A one-wire variety usually won't do it. I don't like electric fans, anyway. They block radiator air flow. If your cooling system is in good shape you don't need it
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| Old Henry | -- 06-15-2012 @ 11:19 PM |
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You can find out how many amps your fan will draw by measuring its resistance in ohms and use this calculator to figure it out. That will give you more of an idea what is going to draw on your generator. Fans I've checked into are anywhere from 15 amps to 25 amps. Your stock generator is rated at 30 amps or 220 watts so if your fan draws 25 amps it would be close if you run the fan and almost anything else even at high speed. Below 30 mph you'd most likely be draining the battery. Here's the calculator: http://www.the12volt.com/ohm/ohmslawcalculators.asp Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 6-15-12 @ 11:23 PM
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| TomO | -- 06-16-2012 @ 9:05 AM |
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Gary, Trying to use your fan, can cause other problems and if you really need an electric fan, you would be better off buying a new one that would work on your car. If you are having overheating problems, I suggest that you try to cure them using the stock items on your car. First, when does your car overheat? Driving down the road or when stuck in traffic? How old is your radiator? When was the last time it was cleaned? What kind of coolant are you using? what have you done to try to correct the problem? Tom
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| Gary M. | -- 06-16-2012 @ 1:45 PM |
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The fan draws too much amperage to run it off the inverter , so I think Ill just buy a 6v fan instead and hang the 12v fan back on the wall for future use in something modern....Thanks for your input...
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| supereal | -- 06-16-2012 @ 2:05 PM |
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You can't accurately determine the current requirements of a fan, or other electric motors, by measuring the resistance (ohms) of the windings. Those devices involve impedence and hystersis, together with starting load requirements. Usually the current requirements are listed on the label. If not, you have to use an Amprobe or other device.
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| Old Henry | -- 06-16-2012 @ 2:28 PM |
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I second what TomO said: There should be no need for an electric fan if the stock radiator is clean, the fan works, the water pumps work, and the thermostats work. If you really do have a cooling problem it would probably be a better use of time and money checking on those things rather than adding an electric fan. Old Henry (The older I get, the better old looks.)
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| Stroker | -- 06-16-2012 @ 4:59 PM |
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I concur with TomO, Super and Ol Henry, and I think "Ol" summed it up. No 32-53 flathead really NEEDS an electric fan. It is a nice addition, if originality is not an issue, but it certainly isn't needed if everything else is up to par. I have driven a 40 Ford truck,loaded with 15,000 lbs of 3-wire alfalfa hay from below sea-level in the Imperial Valley of CA., to our ranch at 2000 ft. in 90 degree weather without having to stop. If everything is "right", a flathead will get the job done. Having said that, Zora Arkus-Duntov had the ultimate solution to Ford truck overheating issues with his ARDUN ohv heads. Much more "interesting" than an electric fan!
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| Gary M. | -- 06-16-2012 @ 8:02 PM |
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I have changed everything possible to make the car run cool, recored radiator with extra tubes, water pumps (not skips), hoses, belts, flushed out block. For the most part the car does not run hotter than it should nor does it overheat. However, when it gets completely warmed up and I stop at a red light , the engine sounds like its loading up and I have to rev it a bit. The engine has never been rebuilt and has low compression , which is what I atribute the problem to . When the engine is nice and cool, I do not have this problem , which is why I want to add the fan. The car is pretty original but its no show car,so im not too worried about adding a small fan.I drive it to shows and meets in the summer in N.Y. and our summers can be pretty brutal!!!
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| trjford8 | -- 06-16-2012 @ 8:34 PM |
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I would try Skip's pumps before I would put on the electric fan. Also another source of heating is your distributor. If timing is retarded or too far advnced the motor will heat up.
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| Old Henry | -- 06-16-2012 @ 10:35 PM |
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Again, it sounds like if you needed a fan at all it would be at idle. And I believe you said you'd run it off of a 6 volt generator. So, to get a 6 volt generator to run an electric fan enough to help at idle you'd have to rev it up?? That would no longer be idle speed and as long as you're reving it up to get the generator to turn the electric fan enough to help you might as well be reving up your stock fan and forget the electric fan. Again, to get any help from an electric fan at idle I believe you're going to need to add an alternator as well. Also, in addition to the timing trjford8 mentioned, is the jetting in your carburetor. I lowered my engine temperature 10 degrees by increasing the size of the jets in my carburetor one notch. Too lean is too hot. Even with the larger jets (51's instead of 49's on my Holley) my plugs are still tan, no carbon build up. Old Henry (The older I get, the better old looks.)
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| TomO | -- 06-17-2012 @ 8:14 AM |
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Gary, An electric fan will probably not help the problem that you described. The loading up of the engine at stop lights could be due to your float level. The modem gas allows the float to sit a tad lower in the fuel than the old gas. Try setting your fuel level 1/16" lower than stock. Tom
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| Gary M. | -- 06-17-2012 @ 2:04 PM |
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I know that my timing is quite advanced but the car doesnt seem to have much power if I retard it. When I posted on this site some years ago about timing , I got several replies saying that because of the fact that the car has no timing marks that if the car runs ok with the distributor as is then leave it alone. Is there any way of getting the timing as close as possible to factory specs without putting the distributor on a Ford timing machine?
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| Stroker | -- 06-17-2012 @ 4:30 PM |
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Well, you can do what we did when we were "Hot Rodding" flatheads. You can fish a stiff rod down the number one plug hole, and find TDC (be sure the piston is coming up on the compression stroke). At that point, you can place matching white paint marks on the timing cover and crank pulley. Using a timing light clipped to the number one spark lead, you can then determine where "you're at". The problem is though, that a slight change in point gap will affect timing, so... you need to have the points gapped properly before you attempt to adjust timing. Proper points gap is necessary for adequate coil saturation, so that takes precedence over timing. Never adjust point gap to achieve correct timing. The early Ford V8 distributor uses dual points to overcome an issue with the geometry of an eight-lobe point cam. In order to maximize dwell (coil charging period), the system uses a pair of points wired so that one set of points "break" the circuit, and a second set of points "make" the circuit. Without going into the details, basically this overcomes the mechanical limits imposed by the geometry of the point cam, which. with one set of points would result in a shorter dwell time as a result of the limited number of degrees that an 8-lobed cam can deliver to a closed set of points, and still provide adequate "lift" to open those points sufficiently to allow for the collapse of the built-up primary field in the coil to generate a strong secondary current to the plugs. So.. that begs the question as to why didn't all 8-cylinder spark ignition distributors in the pre-"Hall-Effect" era have dual points? I don't have a definitive answer, but I would suspect that better materials and design of modern cylindrical ignition coils allowed for the shorter dwell times available in single-point, eight cylinder configurations. The alleged dual-point advantage lived on into the 8BA era however. Mallory (a trusted aftermarket supplier)provided a popular 8BA distributor with dual points, and a single coil. Most folks bought these because they didn't rely on the odd "balance between venturi vacuum and manifold vacuum" limits of the stock 8BA system, and you could use this distributor with multi-carb set-ups without problems. In summary though, if you can find someone with a proper "distributor machine", you don't have to deal with any of the above diatribe.
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| Gary M. | -- 06-17-2012 @ 5:26 PM |
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I am using a modern cylindrical coil mounted away from any heat sources. I will check with my local v8 club president to see if he knows anyone with a distributor machine. Thanks for the input...
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| supereal | -- 06-17-2012 @ 5:45 PM |
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The purpose of a distributor machine is to set the correct "dwell" period . Dwell is the term applied to the period the distributor feeds power to the coil. The greater the dwell, the more saturated the coil becomes, and when the power is ended, the coil discharges, forming the high voltage necessary to fire the plug. If done correctly, the timing is not affected beyond the ability of the slider on the distributor to adjust it. It is also used to test and set the vacuum brake, but the advance is strictly mechanical. Tampering with the preset advance usually only degrades performance. I've set lots of flathead distributors on our Sun machine without regard for timing. From your description, it appears your original engine is just very tired, and ready for a rebuild. This message was edited by supereal on 6-17-12 @ 5:47 PM
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| Old Henry | -- 06-17-2012 @ 9:33 PM |
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Don't need a distributor machine to get initial timing and dwell right on. Just get the points gap right on then follow the instructions in the attached. That will get the distributor right at 4 BTDC. But, that is not necessarily the best spot. That spec is for sea level. As you go up in elevation you can and need more advance for optimal performance. At my elevation of 4,800 feet I run with maximum advance initially and maximum advance on the vacuum brake (scr*w*d clear out) and never get a ping but a lot more power than at the stock 4 BTDC. BTW that also gives me maximum vacuum on the manifold which I think is a great way to set the timing since, for me, maximum vacuum means maximum power. I just had to advance mine all the way at my elevation to maximize the vacuum. At lower elevations vacuum may be maximized at less than maximum advance. Old Henry (The older I get, the better old looks.) This message was edited by Old Henry on 6-17-12 @ 10:21 PM
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| supereal | -- 06-18-2012 @ 9:18 AM |
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If you use an ohmeter with the "ruler" method of point setting, the result will be considerably more accurate. Just place the meter on the "1X" setting, and hook it up between the input terminal and ground. Block off the points, one set at a time, and watch the meter needle. The advantage of machine setting, as said in my post, is seeing the firing pattern on the strobe disk. This will show point bounce caused by weak springs, as well as any play in the distributor shaft and bushings. If the shaft is loose, accurate point setting is impossible.
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