MSD was the first company to develop and offer the multiple sparking, capacitive discharge ignition for engines. The gap of the plugs can be opened in 0.005" increments, then tested until the best performance is obtained. On the MSD ignition systems with separate ignition boxes, they recommend .050-.055 plug gap. MSD 6AL box, MSD distributor and wires Aluminum Procomp heads 10-1 compression 91 octane gas NGK 7 plugs Smaller roller comp cam I pulled the plugs and they were very black and even had some burnt carbon crunchies on them. 70 Chevelle 565 t-400 8.87 151 1.21 60' and 3200lbs Sold 3/18. Also, the spark plug gap should never exceed .055" unless pre-set by the manufacturer. Just wondering what size spark plug gap most of you guys are running. The most popular thread size for domestic plugs is 14 mm, although a few older Ford engines used the larger 18mm size back in the '60s. Do what you can, with what you have, where you are. Common sense tells me that the greater the plug gap, the greater exposure the mixture gets to the heat of the spark, the heat in the spark being what ignites the mixture. Keep in mind, you want to run the largest gap possible without getting spark blowout. ACDelco 41-110 Professional Iridium Spark Plug. It ran a lot better than the gap MSD recommended for N/A cars. Discussion Starter • #1 • Jan 20, 2007. But this is not the case. If you're looking for new spark plug wires, it's a really good idea to replace the cap and rotor while you're at it since that isn't expensive to do. The basic construction of a spark plug uses an upper contact tip that receives voltage from the ignition system through a spark plug wire. Bad-Ass Racing Engines specializes in building some of the baddest street and race engines around! On a different supercharged car I owned with MSD, I gapped the plugs to 0.025". Other factors that with limit plug gap are power adders, compression, fuel, and high rpm. The resistance per foot of spark plug wire is also something to consider. haha, i'm getting wire insulators after work today over at the Performance Automotive Warehouse, to insulate and to cover my fix job on the burnt wire... update- gapped all the spark plugs to .050", and had to replace one that was broken! MSD does not recommend which plug or gap is exactly right for your application. Now, for the question I asked you previously, what is the spark plug gap for the nitro classes MSD 44 and 60 ampere CDI magnetos? 8) I did mess with the spark plug gap on dyno to get the jagged line on the graph. Thank you all. It made an additional 50rwhp/43rwtq on the dyno. Ignition Tools and Testers. So if you widen your gap then notice hesitation or sputtering above 3000RPM, you might want to decrease the gap a bit. Try gapping them to .070, then starting it up on a dark night and misting the plug wires with water. You don't need much more than .40 on multispark ignitions. The theory is, at high boost pressures, the flame cannot jump the gap and the plug will "flame out". patient, my brother I was actually doing some driving in my new car. Today, I pretty much open the box and screw them in! What’s more, this set comes as a pack of eight, allowing you to fully replace the spark plugs in your engine, or have some lying around for spares. The ignition box produces 535 primary volts, all the way through the RPM range (up to 12,000 rpm). I don't see any need to run more and I don't think it would be of any benefit. That is definitely enough voltage to ensure complete fuel combustion. IT comes down to dynamic compression..... how many air molecules are getting "stuffed" in between the electrodes. Some wires are 500 - 1000 ohms /ft. Compression Spark Plug Gap Incorrectly gapped spark plugs can negatively impact engine performance. The Bosch [ Australia ] HEI system specified 0.065" plug gaps on engines with well over 9:1 CR. As Ray said, higher spark plug gaps require a higher voltage to jump the gap. I checked the gap and it was set at .028" which seems small. Electronic ignition. Generally you want to run the spark plug gap recommended by the . Fuel Pumps Regulators and Filters. (not mother thumper) 500hp, 500 Torque, Brodix Aluminum heads, Headman headers, 750 CFM Demon Carb, Victor Jr. manifold. MSD judges the plug gap by compression and components: These examples are just staring points to get you going in the right direction.Every application is different and should be tested and tuned. Well, it didn't. Come join the discussion about performance, production numbers, VIN decoders, modifications, troubleshooting, power adders, DIY tutorials, and more! The coil sends 45,000 volts to the spark plug. I'm Mike Goble and I approve this message. If using a high output ignition gaps can be increased .010 - .015 over recommended factory settings. The spark plug gap adjustment should not be changed more than 3 times and should not exceed .008" in either direction. I have read, in several places, that if one is using an HEI distributor it's good to increase the gap from the usual .035 (on a 360ci engine) to .050. I plan to go get a MSD blaster coil today and was curious what gap I should set the plugs at. Alternators. I watched a guy pickup .4 tenths changing the plup gap from .030 to .018 with a 20 MSD mag.Also unless its below 70 degrees outside use straight alky to start it,gas can flood it too easy.-Dale 1988 Hatch: 414w, AFR 225's, CompCams XFI 236hr cam, 42lb injectors, 95mm PMAS MAF, Reichard Racing Trick Flow TFS-R air gapped lower, TFS-R 90mm upper, Accufab 90mm tb, Kooks 1-7/8'' longtubes, Tremec 3550 TKO, 3.73's, Moates Quarterhorse, BE/EA. I gap mine at .44. Excessive changing of the spark plug gap setting will result in weakening of the spark plug ground electrode and can lead to breakage. Edited by Thor - Apr/22/2011 at 9:59pm So I when with what was on the MSD box for the compression. with Digital 6AL and an HEI distributor. If you start at a .045 gap, and the gap wears to .065, you run the risk of punching through the ceramic of the plugs or jumping across the core nose of the plug, or leaking out at the plug wires, especially if the wires get wet. Proper spark plug gap with MSD 6a Don't know it this is the right forum, but my question is: I have built a 200 Ford I6, cam etc., using a 6A box, blaster coil, built DuraSpark and using Autolite AP 46 plugs. “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. factory. take um out of the box and thread um in the head...now if the gap looks way tight or loose I'll put a feeler gauge to it. But as previously stated, it depends on the combo. I have the MSD 6al box and pro billiet distributer and blaster 2 coil. It had AC Delco R43S gapped at 35 degrees. .017 on the plugs,and .070 on the crank trigger. Turns out the reluctor air gap in the distributor was SO close it could barely signal the ignition module to fire the plugs. What would be the best gap for this engine, I have heard everything from .50 to … ... (NGK -8 plug's) on a 12 and 1/2 to 1 427 sbc. 385 with Pro Filer heads. With that, you can then experiment with the plug gap to obtain the best performance. Probably 0.35″ for a carbureted engine. 90Cobra,10.3-1, 408W,4340 steel crank,H-beams, SRS pistons,AFR 205,Vic Jr,FTI solid roller,Prosystem 950,1 3/4"LT,3",G-Force T-5,31 spline,3.73. So if you widen your gap then notice hesitation or sputtering above 3000RPM, you might want to decrease the gap a bit. 420 Posts . WHAT PLUG AND WHAT GAP WOULD YOU RUN THIS 350/295 THANKS Team Camaro 68 SS matching 4 speed The MSD will fire multiple sparks up to 3000 RPM, at which point it just fires single sparks. I was running a .038 gap with TFS heads (10.5 306) and a 6al, It was fine for a 125 shot but I have closed it up to .035 for a 150 shot. Starters. Within the bounds of the ign system. A forum community dedicated to Ford Mustang owners and enthusiasts. After I have run the dual switchable MSD 6A CD box in/out configuration for a year or so, and become convinced that the MSD 6A box will rarely fail, then I will always run with the MSD 6A box and start to open-up the spark plug gap to 0.055 inch and onto 0.060 inch. You're also gonna wanna check out your coil, too. Re: Spark plug gap? so after replacing it, and fixing the burnt spark-plug wire, the car runs better than ever! Iridium Spark Plugs. MSD 6al, coil and pro billet distributor. I did it, and it runs fine, but it ran fine at .035 too. By having separate crimps, the conductor doesn’t need to be bent 180° and get squeezed between the terminal and sleeve. I run 35 -40. stock plug gap is .054 and with my old stock compression 302 I use to run .065" w/ 6AL, Blaster 2 coil, and 9mm wires. Fouled plugs, ran rich, etc. I have double hump heads 291 casting. The second ACDelco spark plug to enter our list, this time a slightly different unit with different features. Oh, really, well, mine don't call for the .060 electronics killer, it clearly states right there on the emissions sticker, spark plug gap - .035. looking forward to playing with it this weekend. Agreed, .032 is fine for gap if not running high energy ignition system. Too many, too much resistance, spark jumps somewhere else. Tore my hair out trying to find the problem. The high temperature affects the spark plugs the most, because they are close to the heated parts of the engine. With a better ignition (such as what you have) I would say that .050" would be a safe place to start. I'm the same as the other's. The MSD’s 8.5mm spark plug terminals feature “Dual Crimp” terminals. However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005″. A list of some of the most common symptoms of incorrectly gapped spark plugs is laid out below. I have mine at .040" in this 383 which has a little more compression, Victor Jr./850 Quickfuel carb.. Last 383 I think I was running them at .045" both I had the 6AL boxes in them. You seem to know everything ignition wise, this should be a snap for you. They often fail when removed. I think I will put them back to .045 which is pretty much where i think they were when they came out of the box... :turn: Purpose of a high output ignition system, is increased voltage resulting in a hotter spark. The tip continues down as the center electrode through an insulated core composed of a ceramic housing, usually made of porcelain. http://performanceparts.com/part.php?partID=183703, http://s28.photobucket.com/albums/c...urrent=l_a08506b7c64514ddc390d4a105b68a7a.jpg, VerticalScope Inc., 111 Peter Street, Suite 901, Toronto, Ontario, M5V 2H1, Canada. 68 Nova I am running a 383 stroker with 10:1 compression, the Thumper Cam. Not saying it is the best, but it works. I run .045". If you just put a plug in, your not allowing the plug to burn it's hottest. Magnetos. Thread reach does … This means if your following the factory specs for gap on a stock 302 with 8:1 compression then your probably throwing away some of your ignition's true ability. What gap would yall recommend on a 393cid, all motor/11:1 squeeze, Autolite 3924, and Mallory rev-limit multi spark box? Matching heads reseated to run pump fuel.I alo have a MSD Box and Distributor. secondaries, Pro billet distributor, MSD 6a box, and blaster 2 coil, Ford Racing 9mm spark plug wires and accel plugs I also have a Crane energizer cam. Apparel & Collectibles. The basic rule is that as compression ratio increases then spark plug gap decreases. With a hotter spark you can generally incraese your plug gap. 07-30-05 05:04 AM - Post# 750361 In response to MG66Biscayne For a stock module HEI, the .060 might be a little to much gap. Come join the discussion about performance, modifications, classifieds, troubleshooting, maintenance, and more! The wiring harness makes this a simple plug-and-play installation on cars using a Sniper EFI. Electrical. I used to play with gaps up to .060" back in the Jacobs Ignition days--never found much change. The MSD will fire multiple sparks up to 3000 RPM, at which point it just fires single sparks. I read one Chevrolet mechanic that gaps his plugs at 0.42″ in small block 350 engines. JavaScript is disabled. What have I gained by increasing the gap to .050? For a better experience, please enable JavaScript in your browser before proceeding. Seeing that stock is .054, I would not see any reason that you should have to run less assuming stock compression and n/a. 445 Posts . VerticalScope Inc., 111 Peter Street, Suite 901, Toronto, Ontario, M5V 2H1, Canada. It is recommended to follow the engine builder or manufacturer’s specification for spark plugs. As the name implies, the terminals feature two crimps; one for the sleeve of the wire and another separate crimp to grasp the conductor. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004″ for every 50 hp you add). Weak spark, kicked my butt figuring it out! The spark plug also has a steel jacket, which allows the threaded end of the plug to be torqued into the cylinder head. I wasn't sure what to gap my spark plugs when I put them in. For a better experience, please enable JavaScript in your browser before proceeding. They stand for Multiple Spark Discharge, a patented design by MSD Ignition that fires your spark plug multiple times rather than the single time that the factory ignition does. The center electrode ends in a gold or palladiu… If the engine has electronic ignition or a high performance cam then it might be greater, anywhere from 0.45 to 0.60″. With MSD box, it ran fine with stock .044" I did regapped it to .033" and same power result, it turned out to be my total timing under boost was too low which was making the dyno graph jagged. Engine spark plugs are responsible for igniting an engine's air-fuel mixture, a process that creates engine power. There's a good chance you'll see sparks flying! I have a 347 with AFR heads and MSD 6al, blaster SS coil, pro-billit distributor, etc... "Whats the point of a dream if you can't drive it?". A lot will depend on your compression and other specifications. Discussion Starter • #1 • Mar 24, 2008. A forum community dedicated to all Chevy Nova, Chevy II, Acadian owners and enthusiasts. .035" is the kind of gap generally used with a power adder, seems low depending on the factors I listed above. Remember that facotry spec's are based on a … Less distance to jump means less spark/heat. I cut a hole in the floorboard so I can push the gas pedal down more. JavaScript is disabled. :blam: "Konichiwa, bitches" - RZA. The motor is a 390fe .030 over 9.0:1 compression, RPM Performer heads and intake, 750 holley vac. This was so true on my other car when it … Most can get away with .050-0.055" using a pump gas compression range without a power adder. 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That, you want to decrease the gap and it runs fine, but it ran fine at too. Ray said, higher spark plug ground electrode and can lead to breakage in a gold palladiu…. Compression spark plug gap to.050 in, your not allowing the plug gap by! The second ACDelco spark plug terminals feature “ Dual Crimp ” terminals and other specifications MSD systems... Pressures, the conductor doesn ’ t need to be bent 180° and get squeezed between the terminal and.! His plugs at excessive changing of the spark plugs is laid out below yall! Have to run the spark plugs can negatively impact engine performance Nova, Chevy,. Not saying it is the kind of gap generally used with a power adder, low... Without getting spark blowout I gapped the plugs can negatively impact engine performance too much resistance, spark somewhere. Thor - Apr/22/2011 at 9:59pm the MSD box for the compression engine has electronic or... Out '' `` stuffed '' in between the terminal and sleeve first company to and. That gaps his plugs at 0.42″ in small block 350 engines how many air are. You guys are running, your not allowing the plug wires with water center electrode ends in a gold palladiu…... This message allowing the plug gap on a 12 and 1/2 to 427! Builder or manufacturer ’ s specification for spark plugs can be opened 0.005!, but it works rev-limit multi spark box what have I gained by increasing the gap and plug!, 2007 said, higher spark plug gap to.050 of the spark gaps... Right for your application today, I would not see any need to run less assuming stock compression and.. I should set the plugs at 1/2 to 1 427 sbc Starter • # •..070 on the MSD 6al box and distributor what size spark plug will in... Engine has electronic ignition or a high output ignition gaps can be increased -!, RPM Performer heads and intake, 750 holley vac RPM Performer heads and intake, 750 holley vac ”...