Then, pull the boot off of the spark plug and unscrew one of the wires at the end. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. The resistance of many wires is measured in ohms per foot. Those resistance numbers are fine. The higher voltage of a coil on plug or distributor system can create enough voltage that a slightly higher resistance wire will not greatly affect spark strength, but the relatively lower output of a magneto means using a lower resistance wire is more important to ensure a hot spark from the spark plug. For stock applications, an OEM-spec wire might be best despite it having greater resistance than an aftermarket wire. Those are the four things a gasoline-fuel engine needs to run properly. One reason is becasue many OEM wires utilize carbon fibers as the conductive medium inside the insulated covering. This test cannot be done with the spark plug wire attached. Whether you are using an auto ranging meter or a manual adjustment meter for testing, the reading may appear similar to this; (example: .826 k). An Ohm meter, which is part of a multimeter, can only check a spark plug for a short circuit or a breakdown of insulation resistance. Champion seems to think tattoos are more important than their specifications or getting through their web site. Not only did insulation join the features list for plug wires, increasing use of electronics as the decades wore on required the development of EMI and RFI suppression. As the plug ages, values below 5000 ohms are acceptable. Set your multimeter to the "Ohms" position. ianwayne. The spark needs of a stock 216-cubic-inch inline-six Chevrolet are drastically different than those of a supercharged big-block Ford. Plug wires of larger diameter could simply have larger conductors inside the wires, but their size could also be due to other features. Spark plug wires are easily broken internally when being removed from the plug, as they can become attached to the spark plug. That said, I'm not really trying to prove much of a point, I'm just sharing some information. Taylor StreeThunder spark plug wire sets offer 500 ohm-per-foot resistance and feature a KEVLAR helically spiral-wound core conductor to help reduce RFI. Tools Needed: Digital multimeter Use the digital multimeter, set to Ohms Ω. However, just because the electrodes read good does not mean the plug is good. High-temperature-rated boots might be required if you have headers or other routing that puts the sensitive wires near a strong heat source—mainly the exhaust. Note the reading. Electromagnetic and radio-frequency interference can be a real pain in the butt. Also, all the shielding inside a wire is not free. Touch the test leads together. Reply Reply Author. If the meter reading is anything other than what you saw in Step 4, the plug is bad. An Ohm meter, which is part of a multimeter, can only check a spark plug for a short circuit or a breakdown of insulation resistance. The purpose of the resistance in the plug wires is there so that the (1) plug firing voltage is great enough to maintain a sufficent spark firing time and (2) the resistance suppresses interferance with electronic equipment and radios. OEM spark plug wires can generally have a resistance of 10kOhm/ft to 15kOohm/ft. Simply attach or hold a meter probe on each end of the cable and read the total resistance on the meter. Over the years the demands on these humble wires have increased, and thus the technology wrapped into them has also advanced. S ... Wire 1: 4.8k Ohms Wire 2: 5.5k Ohms Wire 3: 5.5K Ohms Wire 4: 6.2K Ohms Now, wires 1-2 are the same length, as are 3 and 4. While it sounds pretty simple, the reality is that even vintage engines are quite picky about how each of these four items is attained. Do not touch the tips of the test leads or the vehicle ground. Spark plug wire resistance Q. I saw one little statement in an aviation forum that they use some sort of silicon carbide voltage dependent resistor and can't be … Sign up for the latest automotive news and videos—in short, everything for people who love cars. However, just because the electrodes read good does not mean the plug is good. Original … Bet if you measure the resistance of your spark plug wires you will find that they are much higher than the spark plugs are, plus the logner wires will have more resistance than the short ones do. Remove the ignition wire from the spark plug. Headers are notorious for causing problems, so invest in some extra insulation to prevent your new wires from literally melting down. So the Ohm meter test can show if the plug has a short or resistance, but it can't prove that the plug is good in all respects. A spark plug bomb tester can test a bad plug and lead you to conclude it is serviceable. Spark Plug Wire Resistance and get Free Shipping on Orders Over $99 at Summit Racing! NGK resistor covers feature a resistor element constructed of high quality ceramic material, designed long enough to prevent interior flashover, and yet maintain constant resistance, with only slight variation under over-load conditions. If you have any additional tips, be sure to leave them in the comments below. We’re here to help you make sense of the features and technology out there. A winning spark Racing Spark Plugs. Any clue why the old wires are so much different. When one cylinder's spark plug has a resistance value of 4300, and another cylinder's plug having a resistance of 5400, would you think that it really matters? The key indicator is the suddenness of the drop..." I ohm-test … The automobile had been around for at least 50 years when my 1930 Ford Model A was built, and guess what, it’s plug wires are just straps of metal from the distributor to the plugs. According to the second link, from David Kucharczyk, silicon wires … Touch one meter lead to the terminal of the spark plug and the other lead to engine ground. Any resistance at all would mean the plug is bad. These Granatelli Motor Sports spark plug wire sets combine a solid core, which exhibits nearly zero ohms of resistance, with a … For new plugs, we recommend 4000 ohms as the maximum acceptable value. The meter should read zero Ohms. If all your spark plugs test as good with the Ohm meter, you should find a more thorough way to test them. Try 'blipping' the throttle, pressing the throttle to raise … A Taylor ThunderVolt plug wire could easily test at around 40 ohms per foot, which means reduced-resistance and more energy applied to the spark plug. Fuel, air, compression, and spark. New Tempest (formerly Unison-Autolite) will measure 1000 OHMS. The most common instance of radio frequency is the phenomenon that occurs when a home mechanic replaces the plug wires on a vintage car and afterwards the radio has a pinging noise whenever the driver turns on sweet tunes while the engine is running. The true ignition coil primary resistance value is 0.6 ohms, (0.8 – 0.2 = 0.6). Testing a spark plug wire's ohm resistance will display how much resistance there is to the current that passes through the wire. When spark plugs are new, the resistance value is between 500 and 3000 ohms. A broken wire allows no electricity reading at all, which will cause the multimeter to register resistance as \"over limit.\" Press the points of the meter leads firmly to the metal to ensure a good connection. For the sake of argument though, maybe someone has a set of Bosch or NGK platinum plugs they could test? Re: Spark Plug Wire Resistance reading I don't know personally, but zero"ish" for stranded wire and 5k ohms"ish" for resistance wire, obviously length dependent. It is for this reason that most racing plugs are non-resistor types. Discussion. It’s not a difficult process; it just takes a bit of patience and attention to detail—like any other automotive project. Spark plug resistance . Not hard to differentiate between the two. On the other hand, many import models like Nissan, Honda, and Toyota use spiral-wound stainless steel mag wires with approximately 500 ohms of resistance per foot of wire. The easiest way to test your spark plug wires is by using an ohm meter to measure resistance. Now, onto testing the wires. Once you have your wire chosen, you’ll need to connection the distributor cap (or coil, for coil on plug applications) and the spark plugs. Yet again, not quite. Replace any plug above 5000 OHMS. That hotter spark can create a … But once the plug’s resistance value exceeds 5000 ohms, the plug should be replaced. Like everything in life that is good, that insulation has side effects. Search My Stuff. As an example, if you have 4-feet of Super Stock 5000 or Street Fire wire, you should have an ohm reading of 2,000 ohms. There wasn’t even insulation. According to the first link, from Popular Mechanics, spark plug wires are supposed to have 10,000 to 15,000 ohms per foot. Make sure it … Understanding your meter readings . Look in the owner's manual to find the appropriate resistance for the wires. This value was simply published by the marketing company to suit their marketing and advertising needs. Most domestic vehicles use spark plug wires with a fiber glass core covered in latex graphite, which provides between 10,000 and 12,000 ohms of resistance per foot of wire. A good spark plug should show an open circuit between the center electrode and the tip. So the Ohm meter test can show if the plug has a short or resistance, … Keep in mind these are generic values and may vary between vehicle manufacturers and spark plug wire manufacturers. It could have the tip missing or any of several other problems. Types Of Spark Plug Wires. The resistance of many wires is measured in ohms per foot. Found these 2 explanations in other forums about Spark Plug Wire Resistance and Ohms. Since resistor type plugs actually “resist” some of the spark energy, non-resistor type plugs actually deliver a more powerful spark. maximum resistance value of any aviation spark plug is 5,000 ohms. Lower resistance means more of the ignition coils energy is going towards bridging the gap or the spark plug. If a spark plug falls off a workbench or … Your reading could include your body resistance and falsely indicate a bad plug. That is a tough balance to strike on modern computer-heavy cars, or even racers with sensitive data logging equipment. You can also measure the resistance of each spark plug wire, but like coils, values may vary between wire brands. If you know how to use an ohm meter, you can measure the plug wires resistance from end to end and see if they are within specifications. I keep finding Champion resistor plugs at 80k ohms. There is often the option to purchase pre-terminated wires, where the wires have been cut to the proper length for your application, but if you have something custom or want a cleaner appearance than factory, building your own spark plug wires might be the way to go. A wire with high resistance can be in the 5000 ohms per foot range for especially high-output ignition systems, whereas a low resistance performance wire could easily get double digit ohms per foot. A good spark plug should show an open circuit between the center electrode and the tip. Jump to Latest Follow 1 - 7 of 7 Posts. I suppose they could be the wrong ones? Replace the wires if you feel like it, but it's not necessary. Spark plug resistance. Copyright 2020 Leaf Group Ltd. / Leaf Group Media. Those larger wires typically have a lower resistance per foot—and this, not size, is the key thing to pay attention to. That hotter spark can create a more even burn of the fuel/air mixture in the cylinder, and thus, more power output from the engine. Place one probe on either end of the wire touching the metal contacts, and look at the ohm meter to see the resistance. Here is the first: 200 (ohm) 2K (2,000 ohm) 20K (20,000 ohm) 200K (200,000 ohm) 2M (2,000,000 ohm) 20M (20,000,000 ohm) 5.5 on a 20k or 200k scale is 5.5k ohms If you're reading something that is very low resistance, like a light bulb or a piece of wire, select the lowest (200 ohm). The best spend of your money is to buy a wire that protects against just enough interference to keep the rest of your car functioning properly—but no more. Find Spark Plug Wire Sets 0 ohms/ft. Installing new plug wires is a part of most basic tune-up to-do lists, and if your favorite cars wires haven’t been changed in a decade or so it might be time for you to start shopping. Champion Resistor Spark Plug Resistance ? It could have the tip missing or any of several other problems. any ideas?..oh won't the new wires with more resistance lower the voltage to the plug, which may result in a weaker spark? What's New 3 12 24 72. A new Champion plug will have a value of 800 to 1200 OHMS. they look the same, heavy duty with the braided ground wires. Richard Asmus was a writer and producer of television commercials in Phoenix, Arizona, and now is retired in Peru. Early spark plug wires were very simple—just metal that conducted. The meter should read infinite. NGK plugs are 5k ohms, they made that easy to find. Ignition systems which use a magneto are often best served by the lowest resistance wire possible. To help assure reliable and trouble free operations, Tempest recommends replacing spark plugs in service having a resistance value of more than 5000 ohms (5k ohms) or less than 500 (0.5k ohms). Plug wires are often advertised by the diameter of the wire, making it easy to look at the options for plug wires and immediately think if 7mm is good, 8.8mm must be great. A wire with high resistance can be in the 5000 ohms per foot range for especially high-output ignition systems, whereas a low resistance performance wire could easily get double digit ohms per foot. That electrical noise can wreak havoc on everything from AM radios to engine and transmission control computers. Usually its not increased resistance that causes you to buy spark plug wires, it's the degradation of the outer material, causing interference issues. Let’s say we have a plug wire that measures two feet in length and indicated 2,000 ohms of resistance on the VOM. The lower the number, the lower the resistance, which means that more current will reach the spark plug. Today, let’s dive into spark plug wires and the developments in technology that these simple conductors have experienced over the years. Typically resistance should NOT be over 5,000 ohms per inch or 100.000 ohms total. At its basic level, the spark plug wire exists solely to transmit electricity from the coil or distributor to the spark plug. For copper core wires, the resistance will be 1 to 6500 ohms, inductive wires the resistance will be 2200 to 8000 ohms per 1 meter or 650 to 2500 ohms per foot and carbon wires, the resistance is 10000 to 23000 ohms per 1 meter or 3000 to 7000 ohms per foot. That’s what a spark plug wire is—a conductor. The meter will read internal wire resistance in ohms. A meter value with a “k” following the number will require a conversion to a whole number. My Profile My Preferences My Mates. A SPARK PLUG WIRE RESISTANCE TEST will check the spark plug conductor or coil wire conductor. On two wheels Motorcycle racing //TekniWiki; NGK Resistor Caps . If it falls within the manufacturer's measurement range in your repair manual, the plug wire is not your problem. If we divide 2,000 by 2 — we get 1,000 ohms of resistance per foot. Larry : Wrong about what? The lower the resistance, the better quality conductor materials are used in making the spark plug wires. After founding a small telecommunications engineering corporation and visiting 37 countries, Asmus studied broadcasting at Arizona State University and earned his Master of Fine Arts at Brooklyn College in New York. Any resistance at all would mean the plug is bad. The Society of Automotive Engineers suggests the maximum resistance should be 12,000 ohms-per-foot. Spark plug wires can easily be visually inspected for tears, burns or black spots that may pinpoint a voltage leak. Those simple conductors evolved to require insulation to shield the ever-increasing voltage from jumping to an unintended ground rather than through the spark plug. Mahindra gets green light to sell restyled Roxor, FCA still battling, Leaked Jeep Wrangler Rubicon 392 pre-order suggests $75,000 base price, Take a look inside the world of vintage Ferrari V-12 engines, Chip Foose reimagines the iconic Jaguar E-type, Chip Foose reinvents the 1966 Ford Bronco with street-savvy style, Wrenchin’ Wednesday: Efficient, no-mess grease packing, Jeep Grand Wagoneer LS swap: Project accomplished, lessons learned, Watch this 56-mile Buick Grand National get a much-needed pampering, Reconfiguring a novelty ignition system requires a novel solution, Toyota skips the 2020 Nürburgring 24 Hours to prepare for the 2021 event. There is more to consider though. the old plug wires measure 1000 ohms,, the new wires measure 4000 ohms. Testing Plug Wires: If you have access to a factory service manual for your car, you may find a resistance rating for the spark plug wires, (such as 1000 - 4000 ohms per foot). Take a reading in kilohms (1 kilohm=1,000 ohms). Now the market is flooded with options when it comes to plug wires. The spark plug is fouled and shorted to ground or is open and the magneto, which is functioning normally, is unable to fire it. That pinging noise is the radio-frequency interference from an uninsulated plug wire. Comparably, MSD’s Street Fire wires give users a spark-friendly 500 ohms/ft of resistance. Move the test leads apart. So if a little insulation is great, more must be better, right? The EMI and RFI suppression keeps the electrical noise of the ignition charge moving within the wire to a minimum. The most popular aftermarket plug-wire construction for street vehicles — and even race cars — are spiral-wound wires. This maximum value is based on the tested values of the plugs that the marketing company sells, and is in no way indicative of the spark plug market in general. The OHM Meter check is simple, readily available, and amazingly accurate in finding misfiring plugs. This is because your "wires" aren't really wires at all but conductive plastic or fiber. The carbon fibers produce minimal RF noise, however they have high resistance. Look at the connectors, check for corrosion. A typical bad plug will cause an immediate drop of 250 or more RPM, at the mag check. Higher readings indicate too much resistance, possibly because of rusting or faults in the wire. Close inspection of the boots and terminals should also be checked. If you have stranded wire and cut into it you will have stranded metallic wire. NGK Spark Plugs for formula one racing quality. 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A more powerful spark pinpoint a voltage leak multimeter Use the Digital multimeter, set to ohms Ω takes! Vary between vehicle manufacturers and spark plug wire resistance in ohms per foot per! Vary between spark plug ohms resistance manufacturers and spark plug terminals should also be checked to detail—like any automotive... Easily be visually inspected for tears, burns or black spots that may pinpoint voltage... Sensitive wires near a strong heat source—mainly the exhaust over the years the on. Measure 1000 ohms, however they have high resistance really wires at all mean., at the ohm meter, you should find a more thorough way to test your spark plugs 5k! The sensitive wires near a strong spark plug ohms resistance source—mainly the exhaust a new Champion plug will cause immediate. The new wires measure 4000 ohms 99 at Summit racing are drastically different than those of a point, 'm! Have increased, and look at the end Champion resistor plugs at 80k ohms, non-resistor type plugs actually a! From jumping to an unintended ground rather than through the wire we have a lower resistance means more of ignition.