Lockjaw Posted September 3, 2002 Share Posted September 3, 2002 Hey guys, Nissan uses a ballast resistor on the ignition system of my 260. Can I just run the power wire to the coil directly and bypass this thing? I have a 300ZX coil I could put in its place if I needed to. It just seems to me like getting rid of the resistor would be a good idea. Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted September 3, 2002 Share Posted September 3, 2002 Are you still using the stock 260 distributor with points? If so leave the ballast resistor. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted September 3, 2002 Author Share Posted September 3, 2002 No it has electronic ignition, like the 280z. Quote Link to comment Share on other sites More sharing options...
jaime240z Posted September 3, 2002 Share Posted September 3, 2002 On my 240 I installed the elec. ignition system made by Crane Cams (hi-6S and the XR3000) I removed the resistor and the ignition works great. If you ever go back to points be sure to replace the resistor. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted September 3, 2002 Author Share Posted September 3, 2002 Is that the thing that installs inside the distributor? I have a points distributor that came out of a 260 engine, but don't want to use it. Quote Link to comment Share on other sites More sharing options...
Lockjaw Posted September 3, 2002 Author Share Posted September 3, 2002 I wonder if that was just not a defective cap, or an old one. I was just planning on using a stock nissan 300zx coil since it is fully capable of firing off my turbo engine at 22psi. I can't help but think that would be a good thing. I am going to try it and see what happens. I don't drive the car everyday anyway, and can always stuff and extra cap and rotor in it. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted September 4, 2002 Share Posted September 4, 2002 Using mechanical points without a ballast resitor will cause excessive sparking everytime the points open and close. This will greatly reduce the life of the points. If you have any type of electronic trigger module, then you can get rid of the ballast resitor by simply removing it and splicing the wires from either end together. Quote Link to comment Share on other sites More sharing options...
Guest HIGHRPM Posted September 4, 2002 Share Posted September 4, 2002 Just a small warning here. In all my years of racing and street performance, I have never had a problem with removing the ballast until now. While the ballast is there to control voltage to the points, One would wonder why the factory would install the ballast with an electronic type dist. Well, several weeks ago, I eliminated the resistor on my early 260, which has electronic type dist. I put on a 40,000 volt performance coil and was rewarded instantly with easier starting and way better performance. This lasted for about two weeks, when without warning the car started missing and then died, all in about two minutes. It would fire up but it felt like it was running on two cylinders. Even with coaxing the gas to bring up revs, it refused. Well, after a $100.00 tow bill, I looked at my fuel system , which was ok. Then I looked at my ignition system and found that the distributor caps coil terminal had been totally destroyed and burnt to a crisp, hense the running so poorly. I've never experienced this in all my years. I have since put the resistor back in, but kept the new coil. Performance is lower but there is no sign of burn out. Any one out there have this happen to them or is this just a fluke??? Anyways, just check your cap periodically so you don't get surprised like I did. Quote Link to comment Share on other sites More sharing options...
MAYHEM Posted April 20, 2003 Share Posted April 20, 2003 Just a small warning here. In all my years of racing and street performance, I have never had a problem with removing the ballast until now. While the ballast is there to control voltage to the points, One would wonder why the factory would install the ballast with an electronic type dist. Well, several weeks ago, I eliminated the resistor on my early 260, which has electronic type dist. I put on a 40,000 volt performance coil and was rewarded instantly with easier starting and way better performance. This lasted for about two weeks, when without warning the car started missing and then died, all in about two minutes. It would fire up but it felt like it was running on two cylinders. Even with coaxing the gas to bring up revs, it refused. Well, after a $100.00 tow bill, I looked at my fuel system , which was ok. Then I looked at my ignition system and found that the distributor caps coil terminal had been totally destroyed and burnt to a crisp, hense the running so poorly. I've never experienced this in all my years. I have since put the resistor back in, but kept the new coil. Performance is lower but there is no sign of burn out. Any one out there have this happen to them or is this just a fluke??? Anyways, just check your cap periodically so you don't get surprised like I did. OK, you all see this is a dated thread, but it's somethig I was wondering. I noticed on my inspection of my '77 Zee, that to my surprise it runs a ballast. Has anyone else had this above problem? or have most people redone there whole ignition ? I have used http://www.jacobselectronics.com/ in the past and was very pleased with them. It works as advertised. Quote Link to comment Share on other sites More sharing options...
MAYHEM Posted April 21, 2003 Share Posted April 21, 2003 Found this blup at this site http://www.geocities.com/zgarage2001/engine.html BALLAST RESISTORS Surprisingly, stock coils on older 12V points systems on every car were designed to operate with a max of 6-8 volts. The reason is that on points distributors the entire voltage from the coil passes through the points, and too much voltage can burn them out. So the ballast resistor was put inline with the 12+ wire to the coil to limit the voltage it puts out. When you turn the key to start, the ballast is bypassed, and the coil gets a full 12V to put out a hotter spark for starting. Releasing the key inserts the resistor back into the circuit to preserve the life of the points. Why not design the ignition to use 12V all the time? Well, nowdays they do, but before 1977 or so that's the way all ignitions were designed. This means if you buy a high performance coil and simply install it, the ballast resistor will usually limit the new coil's power output to nearly stock. So on a points distributor If you connect a wire across the ballast, it will route a full 12-14v to the coil and pick up some voltage, but it can cause the points to burn out more quickly. Don't bypass the ballast if you have a '75-78 280Z. The 280 brain supplies the coil voltage, and removing the ballast can hurt it by making the FI brain supply too much current. 280ZXs supply a full 12v and don't use a ballast resistor. Quote Link to comment Share on other sites More sharing options...
Dave240Z Posted April 25, 2003 Share Posted April 25, 2003 That writeup is close, but a bit vague regarding the principle of operation. There are a few more things to consider about ballast resistors before you can say they are not necessary. An important point of consideration regarding ballast resistors is that they not only control the voltage sent to the coil, but they also control the current. Current is what is actually doing the "work" with electricity (and potentially the harm), voltage is merely representative of the potential. But, since the two are intertwined (V=I/R) altering one inevitably affects the other, but the widespread belief that all a ballast resistor does is alter voltage still exists. Funny, considering that a coil operates on the principle of forcing current through a coiled wire and the subsequent collapse of a magenetic field. Keep in mind, altering the voltage (and current) present at the coil was important when coils could overheat when exposed to voltage for a long period of time, such as when the engine is operating in it's low-speed range. Remember that time is relative and low engine speeds (~3000rpm and lower) mean that the voltage supplied to the coil has more duration since the points are left open longer due to the low engine speed. Of course we're only talking milliseconds but that is quite a time period in electronics. Nevertheless, this can be enough to overheat and effectively destroy a coil. As we all know, the ballast resistor effectively counters this by altering the amount of voltage (and hence current) sent to the coil. It does this because it is resistor (Duh!), but another aspect that is relatively unknown is that it is also temperature sensitive. At low speeds (remember long voltage duration) the ballast resistor heats up, and as it heats up it increases it's resistance thus limiting the amount of voltage sent to the coil to prevent it from burning up when it's protection is most critical. At higher engine speeds, the resistor is not exposed to long voltage durations and as such does not heat up as much. As with all electronics, reduced heat = reduced resistance and therefore the full or near full voltage potential is allowed to pass on to the coil unaltered. You may be asking, OK fine but what does this have to do with points? Well, the points are responsible for "breaking" (hence the name) the primary circuit of the coil to induce collapse of the magnetic field to produce the high voltage output for the sparkplugs. Since the amount of voltage the points must "break" is dependent on the amount voltage present in the coil primary windings which is dependent on the amount of current sent to the coil, they are dependent on the ballast resistor as well. Also, since the ballast resistor is temperature sensitive and sends full voltage to the coil at high rpms, the points also see higher voltage for longer durations as well. This is part of the reason as to why points used to fail so often in race cars. It wasn't just that the metal lost it's spring (although point float is a real problem) but also because of the higher voltage potential and subsequent burning of the points. Something else to consider.... My current ignition system consists of a MSD-6AL, MSD Blaster coil and Pertronix igniter. Originally, I just had the MSD blaster and pertronix installed without a ballast resistor. This worked fine for a while, but then one day the pertronix fried. I thought it may have just been defective or something, and confident that I had correctly diagnosed the problem, I bought another and replaced it. Voila, the car ran fine again. However, on my way to get gas, the new pertronix died. Since then, I did some research (as you can see ) and added the ballast resistor back into the circuit (only for the pertronix since the coil is regulated by the MSD unit) and replaced the pertronix again. 6 months later, no problem. It turns out the pertronix was seeing far too much current due to the high output coil and no ballast resistor. The little unit would work fine for a while, until it heated up, which in turn increased it's resistance, which in turn heated it up which eventually burned it out. So what is the moral of this long story (if you've read this far)..don't discount the benefits of the ballast resitor right away; It just might be useful to you. Quote Link to comment Share on other sites More sharing options...
MAYHEM Posted April 26, 2003 Share Posted April 26, 2003 Excellent read Dave240Z, thanks for clearing this up. Quote Link to comment Share on other sites More sharing options...
MAYHEM Posted April 30, 2003 Share Posted April 30, 2003 Dave240Z, in your experience is it the norm to run aftermarket ignition with a ballast resistors?..... on z's. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted April 30, 2003 Share Posted April 30, 2003 Where has the "condenser" gone in this discussion? My understanding of placing the capacitor across the contacts was to absorb this energy somewhat to help eliminate the point's demise. Nearly all "point" type ignition had this attached to the circuit at one time or another (usually on the side of the distributor itself) Quote Link to comment Share on other sites More sharing options...
Dave240Z Posted April 30, 2003 Share Posted April 30, 2003 Yes I did leave out the condenser in my post; I figured it was already long enough. The condenser's (basically a big capacitor) job is indeed to suppress some of that current rushing to the points, in an effort to minimize an early point demise as you call it. It does this by forcing current back through the coil, thus helping minimize the inrushing current to the points. Of course this happens during milliseconds after each cylinder sparks. I'd love to be able to tell everyone exactly what does and doesn't work regarding ballast resistors and aftermarket electronic ignitions, but my experience is limited to the MSD and pertronix and I am just a shadetree mechanic like everyone else so I'm no expert. I will share what I know though, based on my experience, just make sure you have some salt nearby. I was able to run my first pertronix for over 2 years and 20K miles with no ballast resistor and MSD blaster coil until it suddenly died. Confident the problem was just a blown pertronix after several years of service, I bought a replacement. However, the new pertronix replacement lasted just long enough to get the car warmed up and down the road to get gas before it died. Nothing else was changed. Of note is that the older pertronix "sensor" housing was much larger than the replacement. I guess this larger size meant the older set was more resistant to overvoltage than the newer one, hence the reason it lasted quite a bit longer. Nevertheless, after getting a third pertronix replacement and after consultations with some electrical engineers and books I realized that the ballast resistor was worth giving a shot. After adding it back in, I had no problems whatsoever. Since then, I have added the MSD 6AL into the ignition and have removed the ballast resistor once again, since the pertronix is now isolated from the coil by the MSD 6AL and not subject to massive current inrush. If you download the msd 6 series ignition system installation instructions (http://www.msdignition.com/pdf/6series.pdf) you'll notice that the very first ignition schematic on page 10, which references a basic points system has a note that indicates the ballast resistor is no longer necessary. This is due to the reason I mentioned above. Based on all this, my advice regarding aftermarket point replacements (i.e. Pertronix, Accel, etc..) would be to use the ballast resistor inline with those units. If, however, you have installed an aftermarket ignition system (MSD 6AL, Accel, etc...) then the ballast resistor is likely unecessary since the ignition system is now controlling the coil, effectively isolating the "point replacements" from the rest of the ignition circuit. Quote Link to comment Share on other sites More sharing options...
MAYHEM Posted May 1, 2003 Share Posted May 1, 2003 Dave240Z, thanks. I'm used to dealing with GM (HEI), and when swapping from point/condenser to HEI one thing you would do is chuck the ballast and run a hot wire (12volt) straight to the coil. So it caught me of guard to see one one my '77. Thnks again. Quote Link to comment Share on other sites More sharing options...
Guest MistressMotorsports Posted May 4, 2003 Share Posted May 4, 2003 Dave 240Z or anyone else... I have a 240 with a ballast resistor, MSD blaster coil, and a Pertronix in the distributor. I noticed this weekend that when power is to the ignition circuit but the car is NOT running, the ballast resistor gets too hot to touch and even smokes if left long enough. I found this while diagnosing a short in another circuit of the car, so I don't know if it's normal or a symptom of the other (unsolved) problem. This scared me enough to not drive the car. With the car off but the ignition on, I have 12.5 volts into the ballast resistor, about 7 volts out of the ballast resistor, and about 1 volt on the negative side of the MSD coil. If I disconnect the Pertronix from the coil, so the coil has no negative side connections, and only theh wire from the ballast resistor on the posotive side, I get 12.5 volts into the ballast resistor, 12.5 volts out of the ballast resistor, and 12.5 volts on the far side of the coil. Is this what I should expect or is there something wrong here? The ballast resistor and a spare one I had each measure 1.9 ohms and look visually to be ok. Mike Quote Link to comment Share on other sites More sharing options...
Dave240Z Posted May 5, 2003 Share Posted May 5, 2003 Your heating up problem was probably due to the fact that the pertronix was basically in the "ON' position the whole time you had the key in the ignition. As you noticed, there was a buildup of heat in the ballast resistor, meaning there is current running through it. The reason I say the pertronix is "ON" is because the pertronix is activated by a magnet. Even though your engine was off, the magnet on the distributor shaft was probably in a position which allowed the pertronix to let current flow through the coil as if it was trying to send a spark to a cylinder. This is OK during normal operation, but to leave it just sitting there, basically dumping current the whole timeleads to a massive heat buildup in the circuit. In the future, disconnect the pertronix anytime you are going to be playing with any of the car circuits to prevent it from getting burnt out. The hot ballast resistor is not a problem but the potential for a fried pertronix is quite real. Quote Link to comment Share on other sites More sharing options...
Guest MistressMotorsports Posted May 5, 2003 Share Posted May 5, 2003 Thanks for the reply. If the engine was rotated a little to where the magnet wasn't trying to trigger a spark, would this still be an issue or does the Pertronix draw all the time so it doesn't matter what position the distributor is in? I moved the car under it's own power a few times during my experiments (just a few feet to get it out of the rain) and the symptoms didn't change. Mike Quote Link to comment Share on other sites More sharing options...
Laketowner Posted February 26 Share Posted February 26 There was a problem in the US with HEI distributors not running properly because they has been wired to the ballast system and needed 12volts to operate properly. The condenser on a non ballast system has a different resistance to a ballast system to prevent pointe from burning out. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.