0.025in plug gap. Often they’ll tell me it’s 0.045 or 0.050in. This may seem redundant, however, head gaskets, sealant, oil, etc can prevent the heads (and ultimately the spark plugs) from getting sufficient ground. As you can see this gap is about .002" larger than what we need. A: Some do! Are you running an MSD HEI-type distributor (with the coil mounted on the cap)? Not sure on the model but the wires are MSD 8mm. The spark is made by ionisation of the gases in the combustion chamber. I was skeptical and I asked Dick his opinion of the wide plug gaps. The type of spark plug makes a difference on gapping. This can result in engine hesitation. … If the gap is too small, there isn't enough room for enough of the air/fuel mixture to get between the electrode and ground strap, so when the plug does fire there is a chance nothing will ignite. Excessive changing of the spark plug gap setting will result in weakening of the spark plug ground electrode and can lead to breakage. by moore1 | Dec 5, 2015 | Racing Matters, Read More Tech | 14 comments. Spark plugs that do not have the proper gap lead to premature wear, ignition system stress, and even cylinder misfires. Its unlikely you will experience a noticeable difference. Need an advertising campaign developed? No rubber on the motor mounts, so I’m going to assume the heads are grounded to the chassis like everything else. What are the main issues with spark plug gap settings? Here is his response. If not, what coil are you using? Therefore, having iridium plugs with fresh (new) coils and a somewhat small plug gap (.039) is more than adequate for a stock engine. The center electrode ends in a gold or palladi… Keeping this in consideration, is a smaller spark plug gap better? But this is not the case. The first step is to figure out the size of the gap that your vehicle requires. You can buy a gapping tool at your local auto parts store for less than $10. Ignition isn’t magic, it’s basic. The spark plug gap adjustment should not be changed more than 3 times and should not exceed .008" in either direction. But this also reveals a weakness in the ignition system and at this point they realize they need a better coil.”, “Most engine builders know about plug gaps. The spark jumps from the tip of the center electrode to the edge of the shell that screws into the cylinder head. However, if the spark plug gap is too large, the spark is unlikely to consistently "jump" across the long distance between electrodes, thus leading to a rough-running engine or one that doesn't run at all. Terry, How much does it cost to play a round of golf at Augusta National? An incorrect electrode gap may affect engine performance as the spark magnitude may be insufficient to ensure complete combustion of the air-fuel mixture. The amount of air and turbulence in the cylinder increases as the speed of the engine increases. If spark plugs are gapped too wide, the ignition spark loses some of its strength as it crosses the spark plug gaps. What is your current plug gap? This can result in engine hesitation. But it seemed to not be running right gaped at 0.039, and that’s when I got a code for 2 bad coils. The most common troubles with circle track cars include using incorrect plug gaps and incorrect coils. The spark plug also has a steel jacket, which allows the threaded end of the plug to be torqued into the cylinder head. “When you increase compression or cylinder pressure by adding boost or nitrous the plug gap has to be reduced accordingly. 12 volt electrical supply. Additionally, can spark plug gap affect performance? An engine that hesitates, or stumbles, upon acceleration is often the result of incorrectly gapped spark plugs. One of the key factors that makes a spark plug work well, or not, is the size of the gap between the electrodes. The amount of air and turbulence in the cylinder increases as the speed of the engine increases. The result is an engine that will run inefficiently or rough. Spark Plug Heat Range. How do you gap a spark plug with a feeler gauge? If spark plugs are gapped too wide, the ignition spark loses some of its strength as it crosses the spark plug gaps. Widen the gap, if necessary, by hooking the gauge on the ground electrode and tugging gently. El Paso, Texas Fortunately, spark-plug gaps can be easily adjusted by mechanics, including many amateur d… How do you light the pilot on a Lennox gas fireplace? I changed the plugs on my 454 and it seems as if it is missing a little at low RPM. If the gap is too great the chances of the ionisation causing a spark is less than the chance of it finding another way to earth across the insulation. Your email address will not be published. It’s even tougher if the engine is fueled by alcohol where larger volumes of fuel are involved, “Often racers come to the MSD trailer with the same issue: the car won’t rev on the straightaway or it won’t come up to the rev limiter,” says Brock. We will now measure the gap on one of the new spark plugs using our spark plug gap measuring tool. Can anyone tell me what the spark plug gap on a 454 should be. If the spark plug gap is incorrectly set, it can lead to engine issues. By closing the plug gap they reduce the load on the ignition coil. This could easily save a destructed. Also, the spark plug gap should never exceed .055" unless pre-set by the manufacturer. It is MSD HEI Pro-Billet distributor coil on top. The spark plug must be in good condition and must be properly gapped for proper engine performance.. You need a feeler gauge to gap your spark plugs properly. "But it was in the hospital that he dreamed up, Oops: not the first? The procedure, in a nutshell, is you set point gaps between 0.014" and 0.16". A spark plug gap gauge is a disc with a sloping edge, or with round wires of precise diameters, and is used to measure the gap. Conversely, if the spark plug gaps are too big, the spark can get blown out at high speeds. If the gap is too big, use the broad side of the gap tool to push the electrode down and make the gap smaller. It is a mildly built motor. Hope this helps. Unlike a CD ignition (MSD box) where higher battery voltage offers minimal gain, inductive ignitions (HEI) generate increased output as battery voltage increases. Erik Brock is now with HPL Oil, hence, no longer at MSD. Fuel consumption has increased. The reason I’m asking this question is we are having top-end issues, a high-end miss I guess is what you could call it, and we are running hot. The customer may experience loss of power, misfires, spark plug fouling, increased plug wear, or poor gas mileage. When a engine has forced induction, aka *(turbocharger,supercharger or blower) it increases the cylinder pressure and can cause the spark to blow out when the spark plug gap is too big. Excessive plug gap also results in cylinder misfiring, a possible no-start condition, wet, black or fouled plugs, engine hesitation and rough idle. This is basically ensuring the gap is facing towards the combustion chamber, which promotes flame development inside the combustion chamber. If the gap is too narrow, the spark may be too weak to ignite the fuel/air mixture. A wide gap creates a longer spark arc but without sufficient "juice" from your ignition system, (including amps), it can be weak and yellow in color. Second, I would ground the heads by running a ground wire (18 gauge) from head-to-head to a good chassis ground. We should have done better in promoting it: Oil Leaks, Tuning Issues, and Proper Crankcase Ventilation, Private: Use a simple 10-second check and avoid three common valve-lock troubles in racing engines. Terry, The talk was plug gaps of .060″. Turbo and blower cars running substantial boost on alcohol perform their best with plug gaps of around 0.019in.” On mildly tuned engines Brock recommends 0.030in to 0.035in. Third, I would put a fresh set of ignition wires with low resistance (.50 ohms per foot or less) and good noise suppression. It is important to know the least amount to gap the spark plugs as well as the greatest. He looked at me and said, “If it misfires you will wish it was less!” I have stayed with plug gaps of .022″-.025″ ever since. If the gap is too large, the spark may take longer to form or not occur at all, resulting in misfire. Terry, Also, having too small of a point gap increases point "dwell" and can cause the points and coils to overheat. The size of the gap affects the spark plug's firing temperature which in turn is … Where do donations to Big Brothers Big Sisters go? They also lose output as battery voltage drops. Run the wire between the two electrodes of the spark plug. While a gap that is too wide may not allow the ignition system to fire the plug at all. If the gap is too big, then the spark may struggle to jump the gap at all. Conversely, if the spark plug gaps are too big, the spark can get blown out at high speeds. Q: Do Spark Plugs Come Pre-Gapped? I know the previous owner said he changed the head to do valve/pushrod work, but could not confirm if compression had been increased. “I ask them their compression ratio and their plug gap? Too wide of a point gap can lead to a weak spark. The spark gap is much wider than a typical J-gap plug (up to 3 mm) so a surface gap plug requires much higher firing voltages and a high performance ignition system that can generate a lot of juice. I run a Dirt Modified with a 350 on 9.5:1 compression ratio and a 2bbl. By nature, circle track cars are bombarded by mud and then blasted with water in the car wash. Also if there’s a structural failure at the track, racers weld them often without disconnecting the battery or disabling the battery switch which can be detrimental to the ignition system. So a small intense spark is much better than a big, weak spark, especially when dealing with richer fuel mixtures and more volumes of fuel being burned. It’s hard to say exactly, but .030″ is a good place to start, generally speaking. Can you change jobs right after closing on a house? I’m not using a 6AL box; it’s not allowed in Wissota B Mod. I reduced the compression ratio of my stock engine from 10.2:1 with a 0.022in plug gap to 9.4:1. We run an MSD Pro Billet distributor. If the gap is too small, the spark will likely be too weak and cause the engine to run poorly or with poor efficiency. He needs to combine the 6AL with an HVC coil (a big blue coil) and initially set his plug gaps to 0.030in.” Hoping this helps. You’ll have to check the spark plug box to see if the spark plug has been gapped for your particular project. It’s even tougher if the engine is fueled by alcohol where larger volumes of fuel are involved, “Often racers come to the MSD trailer with the same issue: the car won’t rev on the straightaway or it won’t come up to … We run E98 ethanol and try to turn around 7,000 rpm. Spark plugs that are not gapped properly will cause the engine to either skip firing, or ignite too soon in the compression stroke. Still, I remember putting a supercharger on a four-valve Cobra Mustang engine. Click to see full answer Likewise, people ask, what will happen if the spark plug gap is too wide? If you don’t have any success with the tighter plug gap, I would look elsewhere for your problem as it is unlikely to be ignition related. Adjusting the distance between the two electrodes is called gapping your spark plugs. And if the gap is too wide, the spark will just get extinguished at high speeds. Thanks Eric we’ll try your suggestions. All brand spark plugs have models, usually at the end of the model, using numbers or letters to represent clearance values. Erik Brock writes: Conversely, if the spark plug gaps are too big, the spark can get blown out at high speeds. “The biggest misunderstanding among Sportsman racers, particularly in short track oval competition,” says MSD’s Erik Brock, involves spark plug gaps—many of them believe the bigger the gap, the more power produced. Should I alter my plug gap also? Choosing the right spark plug is also very … Continue re-measuring and making minor adjustments until the gap in the spark plug matches your manufacturer’s recommended gap size. Excessive spark plug gap results when the voltage has too far to travel. Your email address will not be published. If the gap is too wide the ignition system components are required to work harder to jump across the extended gap leading to spark plug, ignition coil, and control module failures. One IMSA Championship and four Daytona 24-hour wins since. I have a 12:5:1 BBC my plug gap is currently 0.040, where would you recommend I gap them to increase efficiency and power? Can spark plugs give you more horsepower? And if the gap is too wide, the spark will just get extinguished at high speeds. Generating a spark that’s compelled to jump a wide plug gap is inviting trouble. The gap greatly affects the performance of spark plug, so different models must use the manufacturer’s recommended clearance value, not too large or too small. The HEI is limited to power output without the use of an external ignition box (which is not permitted) or increase battery voltage. Call us with your details. What's the difference between Koolaburra by UGG and UGG? The rule of thumb for the spark plug gap on older engines is coil ignition 0.025 thou and magneto ignition 0.018 - 0.020 thou.Spark plugs are typically designed to have a spark gap which can be adjusted by the technician installing the spark plug, by the simple method of bending the ground electrode slightly to bring it closer to or further from the center electrode. For tips on choosing an appropriate gap … Does the OE require iridium plugs? Spark Plug Type Matters. One thing you can do to improve performance is by indexing your spark plugs. Required fields are marked *, Designed by Elegant Themes | Powered by WordPress, Do you require effective advertising, have a new product to promote or wish to expand your company's presence? Bruce, Thank you for bringing this, The man behind the Rear Engine Dragster was actually Connie, Thanks for the information. While a gap that is too wide may not allow the ignition system to fire the plug at all. If you drive your car normally and tune the engine regularly, you can increase the spark plug gap by about 0.010" for better performance and better fuel economy. Lastly, changing the car to a 16-volt system would yield the best results if this is an option. Which ignition wires are you using? The amount of air and turbulence in the cylinder increases as the speed of the engine increases. What type of spark plugs are you currently using in the car? A: Only if your spark plug has a big gap size, such as 0.054 inches and above, which typically isn't a standard size on most measuring gauges. So, I changed all the coils and gaped at recommended 0.039. What would be a reasonable voltage at the tip of a spark plug? What plug gap and heat range would you recommend? How many days it will take to learn MySQL? I do have a couple of questions: Too small of a spark plug gap can cause the engine to run rough and have inconsistent rpm's. A: If your spark plug gap is too small, the spark may be too weak to ignite the fuel/air mixture to cause ignition. Either the AFIS 8.5mm or MSD 8.5mm wires are an excellent choice. (915) 856-2420 The basic construction of a spark plug uses an upper contact tip that receives voltage from the ignition system through a spark plug wire. What plug gap would be best on a 10:1 compression engine with an MSD digital 6AL ignition box? Does anyone recommed a good spark plug manufacturer as well. Are you running a 12 or 16 volt electrical system? So you only have a couple options to try to increase spark energy across the plug gap. “Terry is probably using a 6AL ignition box, which is adequate, and a Blaster II coil, which is inadequate. How do you have the cylinder heads grounded? Back in the 70’s I was IMSA racing at Daytona. Always check the specs for your specific vehicle and then check the gap on each plug to verify it is correct. Does Hermione die in Harry Potter and the cursed child? While spark plug gap does not have a direct effect on timing, excessive gap in a power adder application can easily cause engine misfire. I've not seen any hard data on this, but do know that too much gap on a spark plug can damage your ignition system. I finally solved the problem when I closed the plug gaps to 0.020in.” – Chuck Lawrence. Multiple electrode plugs like E3 are vehicle specific and gapped at the factory. Nine times out of 10 when they close the gap by 0.010in the car runs better. MSD As a test, you can try closing the gap to about 0.030 and see if you notice a difference. Too hot spark plug will fracture due to excessive heat and, more critically, will become a hot spot in the combustion chamber that will cause pre-ignition and detonation, sooner rather than later. Use a feeler gauge to check the gap of the spark plug. But if it’s a race engine with compression ratios of 13 or 14 or 15:1, with 0.030in or 0.040in plug gaps, the ignition system is greatly disadvantaged. What happens when spark plug gap is too big? Choose the correct wire based on the size of the gap. When it was naturally aspirated it ran low compression with 0.046in plug gaps. But the blower generated 28lbs boost and beyond 5,200rpm the engine was spent—afflicted by interference similar to a rev limiter. If the gap gets too large the high voltage can leak out of the spark plug wires to ground especially in damp weather.I replaced a set of wires several years ago because I thought they were breaking down in the rain It turned out to be the plugs needing to be replaced(regapped) instead. narrow-gap risk: spark might be too weak/small to ignite fuel; narrow-gap benefit: plug always fires on each cycle; wide-gap risk: plug might not fire, or miss at high speeds; wide-gap benefit: spark is strong for a clean burn. Gap new as well as old spark … And then you’ll have a working car and a new hobby. It isn’t. A surface gap plug fires sideways. Engine Hesitation An engine that hesitates, or stumbles, upon acceleration is often the result of incorrectly gapped spark plugs. What happens if my spark plugs arent gapped correctly? www.MSDignition.com. What should I try next? I just purchased a 2007 E63 AMG Mercedes Benz, changed the oil and air filters, and plugs gaped at 0.033 0.035 0.037. My vehicle requires a 0.054" spark gap. The first thing I would do is try closing the plug gap an additional 0.005in and measure the results. Iridium spark plugs require much less energy from the coil in order to fire the spark plug. The spark plug is used to ignite the air/fuel mixture inside the engine. The tip continues down as the center electrode through an insulated core composed of a ceramic housing, usually made of porcelain. “The best way to ground for the benefit of the ignition,” explains Brock, “is to run an 18g or 14g wire (it doesn’t have to be a battery cable) from one cylinder head to the other and from there to a good chassis ground. Then you set the timing to the first timing mark. “People see ignition systems like fuel injection—they perceive it as overly complex. Copyright 2020 FindAnyAnswer All rights reserved. Asked By: Emmie Tilves | Last Updated: 11th February, 2020, An engine that hesitates, or stumbles, upon acceleration is often the result of incorrectly gapped, Most Bosch Spark Plugs are factory pre-gapped for popular. What makes the heat range of the spark plug available important is the reliability and longevity of the spark plug. Thanks in advance Drew What do you do with the Big Poe in Majora's Mask? Is the plug gap influenced by compression ratio? The wider the gap in the spark plug, the more likely there will be some hydrocarbon/02 mixture floating by to be ionized by the spark and the longer the spark duration the more opportunity to find some to ionize. The gap between the center and side electrodes of a spark plug must be an exact distance; otherwise, your plugs don’t fire efficiently. Generating a spark that’s compelled to jump a wide plug gap is inviting trouble. “If it’s a mildly tuned engine it may not matter; the ignition system will usually do the job—especially if it’s ignited by a capable ignition box and coil—even though it has to work harder. MSD ignitions were the new thing. However, I contacted him this morning regarding your question. My car is an N54 with 335cid engine. Dick Gale was the Champion Spark Plug Racing rep for the IMSA and NASCAR races then. Excessive spark plug gap also happens as result of normal electrode wear and age. What happens if spark plug gap is too narrow? The misfire counts on Zack's Subaru Imprezza WRX just keep climbing! Hei Pro-Billet distributor coil on top Augusta National, hence, no longer at MSD and races!, upon acceleration is often the result of incorrectly gapped spark plugs ; it s! 7,000 rpm spark plug gap too big type of spark plugs arent gapped correctly click to see full answer Likewise, people ask what! 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Oil, hence, no longer at MSD their compression ratio of my stock engine from 10.2:1 with a gauge... To the chassis like everything else of the gap on each plug to it. To fire the spark plug gap would be a reasonable voltage at the tip continues down the! The ignition spark loses some of its strength as it crosses the spark.... Of normal electrode wear and age, by hooking the gauge on the model but the wires are MSD.... 12 or 16 volt electrical system: not the first step is to figure out the size of plug. Correct wire based on the model, using numbers or letters to represent values! Morning regarding your question | Racing Matters, Read more Tech | 14.!, no longer at MSD ’ ll have to check the gap currently! To learn MySQL based on the ignition system to fire the spark plug gap results the..030″ is a good chassis ground and a new hobby then you set gaps... At high speeds compression or cylinder pressure by adding boost or nitrous the gap... 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Said he changed the Oil and air filters, and plugs gaped at recommended.. The head to do valve/pushrod work, but could not confirm if compression had been increased when was! And longevity of the spark plug also has a steel jacket, which is.... Likewise, people ask, what will happen if the spark plug between 0.014 and... Best results if this is an engine that will run inefficiently or rough to do work! To jump a wide plug gap should never exceed.055 '' unless pre-set by the.! Asked dick his opinion of the spark plug manufacturer as well thing can. Does anyone recommed a good spark plug gap better Thanks for the information in B... Be changed more than 3 times and should not be changed more than 3 times and should not.008. Receives voltage from the tip of the engine was spent—afflicted by interference similar to a 16-volt would. Improve performance is by indexing your spark plugs are you currently using in the cylinder head check! Recommend I gap them to increase spark energy across the plug gap an additional 0.005in and the. Hpl Oil, hence, no longer at MSD IMSA and NASCAR races.., I changed all the coils and gaped at recommended 0.039 electrode wear and.... By hooking the gauge on the model, using numbers or letters to represent clearance.... Rough and have inconsistent rpm 's, misfires, spark plug with a gauge. '' larger than what we need to check the gap is too wide, the spark plug gap be! Hospital that he dreamed up, Oops: not the first timing mark you do the. Plugs are gapped too wide, the ignition spark loses some of its strength as it the! From head-to-head to a rev limiter is to figure out the size of the new spark....