Leon Posted September 2, 2011 Share Posted September 2, 2011 (edited) I'm planning to install EDIS in my Z using Derek's trigger wheel and sensor mount. I plan to use Megajolt to control spark while keeping my triples, along with the rest of my engine the way it is. This means that I'm keeping the stock clutch fan and do not plan to use an e-fan. The problem is that apparently there is interference between the stock fan and VR sensor mount. The first solution I thought of was to make a spacer. The spacer would be very simple, but it would require custom machining and new fasteners for the fan. I decided to search to see if others have faced this problem and how they solved it. Somewhat accidentally, I discovered that the 280ZX cooling fan extends further towards the radiator than the S30 unit in order to accomodate a three-row damper. If you think of the cooling fan as analogous to an automotive wheel, imagine that the cooling fan's "offset" went from positive (S30) to negative (S130), thereby extending the fan towards the radiator. What I need is for someone to measure a 280ZX fan width and distance from the front-most part of the fan to the hub. A ZX fan is identified by the mounting hub being at the back of the fan. Or, maybe someone has experience running a 280ZX fan in an S30? I'm using a 2-row Champion e-bay radiator, and there is currently a little over and inch of radiator-to-fan clearance. 240Z Fan 280ZX Fan Edited September 2, 2011 by Leon Quote Link to comment Share on other sites More sharing options...
luseboy Posted September 4, 2011 Share Posted September 4, 2011 Im confused on why you don't just use an e-fan setup. They're relatively inexpensive, and if you went with pushers, you would have tons of clearance... Personally, I plan on doing two 10" pushers in my z (if they fit), when I get it. But I don't have my z yet, so I don't know what kind of room there is in front of the rad. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 4, 2011 Share Posted September 4, 2011 (edited) I just removed a hacked up 280Z fan from a 77 and replaced it with an 82 fan. There is at least 3/4" difference between the two. The 82 fan is further forward. The 77 fan blades had all been cut on the backsides to clear for an aftermarket AC clutch. FWIW, I installed a 3-row Champion alum rad, the 82 fan and clutch, and the 77 shroud, into a 77 S30. I had to raise the shroud AND the radiator to get the fan to center in the shroud. I may also have access to a 1/2" fan extension ring. I think I even have the longer studs you would need. Edited September 4, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 4, 2011 Share Posted September 4, 2011 (edited) I have found lug nuts in there as spacers... I think washers may be a bit lighter. Spacing the fan is what you do if you don't have the right clutch in stock and need clearance. No biggie. Make it fit. The reason the fan is plastic is the overhung load is reduced to effectively nothing. There is more load on the bearings of the clutch unit when the fan is moving air, than on the bearings of the water pump from weight (think why they went from the metal fan on the early 240's...) Frankly, overtightened belts on the alternator have done in more bearings in water pumps than fan overhung moments! The ZX Fan on a ZX Clutch is close to the radiator, in some chassis close enough you want to make sure you have good motor mounts! It's really close if you have a four-core. But it clears. Where the mounting tabs are is the fan difference, in addition to blade count in some cases. The clutches can be 'made to fit' using spacers, no problems, like you said, just use longer bolts. A nice machined spacer ring (or thin ones so you can adjust the fan position in 5mm incremets...hint hint) would make things easier. Were they made of phenolic or lexan/polycarbonate sheet that would keep them lighter than aluminum as well, for those concerned about that kind of thing. Titanium would be overkill, but really give you bragging rights! Then again, with a CNC Machining Center, you could probably make a billet Titanium fan with the offset you wanted and then polish it up to look REALLY KILLER (literally as well as figuratively!) Edited September 4, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
Leon Posted September 4, 2011 Author Share Posted September 4, 2011 (edited) Im confused on why you don't just use an e-fan setup. They're relatively inexpensive, and if you went with pushers, you would have tons of clearance... Personally, I plan on doing two 10" pushers in my z (if they fit), when I get it. But I don't have my z yet, so I don't know what kind of room there is in front of the rad. (1) Cooling: the stock fan cools better, or least good enough for my application. Temps never rise, even in 100+ degree weather. (2) Simplicity: no need for putting in a new electrical circuit with the stock fan. (3) Electrical Load: would need to upgrade the already-weak stock alternator if using e-fan. (4) Cheaper I just removed a hacked up 280Z fan from a 77 and replaced it with an 82 fan. There is at least 3/4" difference between the two. The 82 fan is further forward. The 77 fan blades had all been cut on the backsides to clear for an aftermarket AC clutch. FWIW, I installed a 3-row Champion alum rad, the 82 fan and clutch, and the 77 shroud, into a 77 S30. I had to raise the shroud AND the radiator to get the fan to center in the shroud. I may also have access to a 1/2" fan extension ring. I think I even have the longer studs you would need. Cool, sounds like it works but I would need a ZX fan clutch as well. I may be willing to take that spacer and studs off your hands if I don't use a ZX fan or am too lazy to make my own. I have found lug nuts in there as spacers... I think washers may be a bit lighter. Spacing the fan is what you do if you don't have the right clutch in stock and need clearance. No biggie. Make it fit. The reason the fan is plastic is the overhung load is reduced to effectively nothing. There is more load on the bearings of the clutch unit when the fan is moving air, than on the bearings of the water pump from weight (think why they went from the metal fan on the early 240's...) Frankly, overtightened belts on the alternator have done in more bearings in water pumps than fan overhung moments! The ZX Fan on a ZX Clutch is close to the radiator, in some chassis close enough you want to make sure you have good motor mounts! It's really close if you have a four-core. But it clears. Where the mounting tabs are is the fan difference, in addition to blade count in some cases. The clutches can be 'made to fit' using spacers, no problems, like you said, just use longer bolts. A nice machined spacer ring (or thin ones so you can adjust the fan position in 5mm incremets...hint hint) would make things easier. Were they made of phenolic or lexan/polycarbonate sheet that would keep them lighter than aluminum as well, for those concerned about that kind of thing. Titanium would be overkill, but really give you bragging rights! Then again, with a CNC Machining Center, you could probably make a billet Titanium fan with the offset you wanted and then polish it up to look REALLY KILLER (literally as well as figuratively!) Great idea on using PC or thin rings! I have an ebay 2-row Champion radiator that I believe is dimensionally equal to the stock unit. I measured current fan-to-radiator clearance at a bit over an inch using a '72 fan. Sounds like both options are viable, and it comes down to what is easier/costs less. A CNC-machined Titanium fan would be sweet but is not within the budget of this project! Thanks for your input, all! Edited September 4, 2011 by Leon Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted September 4, 2011 Share Posted September 4, 2011 (edited) The owner of the 77 was making a 1/2" extension ring in aluminum, for the 77 fan/clutch to clear the A/C clutch without having to cut the backs of the blades. When I put the 82 fan assembly in we realized he didn't need the ring. I will see if he has the ring available, if you choose that route. Edited September 4, 2011 by cygnusx1 Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted September 4, 2011 Share Posted September 4, 2011 (edited) I have 3/4 inch between radiator and fan and about 5/16 inch between the fan blades and the 280zx front pulley. I played around with different fan clutches and blade combinations from the junkyard and am currently using the 240sx clutch and what I think is the 280zx blade......but it might be 1984 maxima.....might be the same as 280zx, though. The 240sx clutch is 2.3 inches long from flange to the face with the thermo bi-metal. It's 1.8 inches from the flange to the stock mounting surface. This will definately put the blade into the radiator on my L28et Infiniti M30 so I simply mounted the blade to the other side of the clutch (same rotation...not backwards). I used longer bolts and screwed them so the heads bottomed on the surface where nissan intended the fan blade to mate (bolts pointing toward back of car) and used what protuded through the other side as studs.......which I screwed standard home depot metric nuts to use as the "spacer". You can always substitute the 3/16 thick nuts for thinner washers to get further away from the pulley or thickness to get closer to the engine. I may have had to grind the inside metal lip on the fan blade at a 45 degree angle to clear the clutch fins but don't remember if it was necessary after using the nuts as spacers. Because the center hub is no longer centering the blade, I just turned the blade and clutch opposite directions forcefully while tightening it which centered the studs in the holes far better than I thought. This causes centering on the bolts/studs and I have driven this combination for 25,000 miles. This setup gives from 1/4 to 3/8 clearance of fan blades to crank pulley with provision for a/c and power steering. Remember to measure any washers you might use for spacing since many found at places like home depot vary in thickness. Some L28 pulleys (maybe 1981 turbo?) have the outermost pulley being removable....just not sure which one. One thing to do is to check for fan blade contacting anything whenever you are under the hood (you will see the evidence on the blade) and occasionally rev the engine while watching both with clutch cold and free and when warm and fully engaged since wear in the fan clutch can cause the blade to move outside of where you would like. When things are this close, a wearing clutch or water pump can cause the blades to hit where they should not. I sometimes use a timing light in the dark when viewing rotating parts to check for clearance. Once you know your dimensions, it's easy to go to the u-pull yards and audition many different combinations there for measurement.....without spending any money but also keep in mind that nissan made at least two different bolt circle diameters with the trucks/pathfinders having a wider pattern than the 280zx/240sx. That said, every single clutch I have come across has a different temperature at which it "comes on" and I've spent considerable time carefully bending the super brittle spring to get the perfect combination of noise vs cooling performance. (care must be taken since the aluminum shaft the spring acts on is fragile and will break internally if you turn it too hard or too far.........they should move very freely with light turning pressure from a screwdriver inserted into the gap between the spring and the shaft it mounts to) I've got 25,000 miles on the setup at the very least but one thing to know about having a fan blade very close to the radiator is that drivetrain movement during hard deceleration at high rpms might induce it to strike the radiator when it would not under all other circumstances. This can happen because high fan rpms will pull the fan blade tips toward the radiator a bit and hard deceleration will cause soft mounted drivetrain to move toward the radiator. Add the two together and you could have issues if you are that close. I'll try for some pics of different combinations later. Edited September 5, 2011 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 5, 2011 Share Posted September 5, 2011 (edited) "I've got 25,000 miles on the setup at the very least but one thing to know about having a fan blade very close to the radiator is that drivetrain movement during hard deceleration at high rpms might induce it to strike the radiator when it would not under all other circumstances. This can happen because high fan rpms will pull the fan blade tips toward the radiator a bit and hard deceleration will cause soft mounted drivetrain to move toward the radiator." I will second that---and it goes for STOCK FANS IN THE FAR BACK POSITION AS WELL! I trashed the radiator in my 75 Fairlady on an improper downshift that pegged my tach and almost locked my rear wheels. Fan blades pulled right into the radiator core and cut about a dozen tubes, some in two places top and bottom of it's arc. Same thing can happen at higher rpms if your fan clutch locks up and you downshift radically! My 260 fan is fractured from overspeed from driving at speeds I shouldn't for extended periods with a locked fan clutch. Cost me about 4mpg to boot. Changed the clutch and a new fan...wonderous again, and ooooh the POWER! I believe the fan clutch starts slipping to keep fan speed below 2500 rpms. If it gets hot enough (Palm Springs on a 110F+ Day going 85+ mph up the grade) that fan will 'kick in' if you have a 190 thermostat in the car, because the air off the radiator will get above 200F and engage the silicone clutch inside the assembly. Run a 160F thermostat and it rarely engages under the same conditions. I guess the low temp thermostat is a 'fan saver'... Edited September 5, 2011 by Tony D Quote Link to comment Share on other sites More sharing options...
Leon Posted September 5, 2011 Author Share Posted September 5, 2011 Great input, I really appreciate it! Thanks for the heads-up HowlerMonkey, I wouldn't have thought to try different model clutches. I would definitely like to avoid any interference, but I don't do much high speed driving, just autoX for now. Hopefully, that problem will not manifest itself. Again, thanks for the great feedback! Quote Link to comment Share on other sites More sharing options...
Leon Posted August 12, 2012 Author Share Posted August 12, 2012 (edited) Wow, time flies... I bought a used ZX fan a while back and finally installed it today. Works great! 240Z to 280ZX fan comparison Installed Edited August 12, 2012 by Leon Quote Link to comment Share on other sites More sharing options...
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