Spark plug mod to eliminate hesitation + free a HP or 2, quicker rev

[Bushwick]

This mod isn't exactly "new", but it was never embraced initially by the plug companies until more recently, but they still leave some on the plate in the less expensive plugs and aren't exactly doing it correctly. This mod works on ANY standard plug. 

 

History: About 15 years ago I was reading through a vintage (mid 1970's) drag racing magazine where the writer was trying to get his 65'-66' Mustang with a 289 to run as fast as possible in the 1/4 mile. He did a series of mods, 1 at a time, then did several runs to see if an improvement occurred or not. Being the the 70's with manual fuel pumps and carbs, getting an extra 1-2 sec in the 1/4 wasn't easy w/o engine swaps, etc. A mod that stuck out was this plug mod. I think he picked up a 1/10th of a second in the 1/4 or thereabouts with the V8. This mod can free up around 5hp on an 8 cylinder engine, so figure roughly half that on an NA 4 cyl. engine that's running correctly and in good tune. MPG is a touch better as is throttle response. Engine will just climb through the revs as it's getting quicker access to the spark. Hardcore racers will index their plugs so they all sit exactly the same way and face the incoming charge, this is essentially the same effect in that the charge has direct access to the spark w/o trying to get around the bulky ground strap.

 

I've done this in all my cars since, from a 10:1 compression 306 Ford, to more modern DOHC 4.6L Ford, to 20+ psi in my Saab, to lawn mowers and my Legacy. Spark never "blew out" so to answer the thought, the spark won't get "blown out". Interestingly enough in the 4.5hp push mower with a new blade, it'd bog on 6" to 10" of high grass (even with 93 octane). The plug mod in that allowed it to cut right through the grass, every time, which backs-up my real world driving experiences. It's like removing clogs from a water line where the water can flow correctly or like giving the engine caffeine to where it's just more alive. This also works on motorcycles.

 

Basically, the ground strap the electrode arcs against is often too long and bulky and shrouds the spark heavily. When the incoming charge hits the plug, it has to go around this large obstacle before firing. This causes a minuscule delay with the combustion event from having to get around it, and the square edges of the ground strap cause small amounts of turbulence, which can also hinder the time it takes to fire off the combustion event.

 

 

Newer plugs like the stock NGK, Autolite, etc. that are meant for our Exxx series, have finally shortened the plug's ground strap, much like how the "mod" from the 70's was done. Autolite terminates the grounding strap a little long. I found on the NGK "V Power" plug, they shortened the grounding strap even further, by about 10%, BUT they still leave the squared edges on the ground strap. The "V Power" also has a small "V" channel groove in the electrode tip, that runs through the center and in the direction of the grounding strap. After using this NGK "V Power" plug with the corners manually filed off the grounding strap and the strap overhang brought back from 10% to roughly 15%, the improvement was night and day with my EJ22. Even with a bunch of weight in the car (talking 200 pounds throughout plus another 165 for me), the car just pulled. No hesitation.

 

I originally hadn't bothered doing this with the Legacy Wagon as it was just a no-power commuter. I promised to do a quick video for a member and went ahead and got another set of plugs and decided to replace them. The results were so positive I figured I'd share considering a free hp or 2+ the complimentary MPG bump were worth spreading. And the fact the engine is climbing quicker than previously, it's worth passing along. I'm very happy with the results from this engine.

 

 

http://i1211.photobucket.com/albums/cc425/Ryan__Smith/Sparkplug%20Mod.mp4

(sorry, it won't embed the link as a pop up)

 

 

Take a fine mill file (couple bucks at parts store) and carefully round the edges OFF the ground strap edges. Think of it as filing a fingernail. Make sure the angles are smooth and flowing and even. Consistency counts! Try and leave the flat edge alone and focus on the edges. No need for heavy force either as the metal is mild steel. I suggest inserting a small section of cardboard like in the video in between the gap to protect accidentally slipping and nicking the electrode. Once the plug's ground strap is "rounded" like in the video, move on the next plug, using the 1st one as a template. If you want to shorten the strap a tad more, focus on the edge I told you to leave alone. From aside profile, I suggest making sure the strap covers at least 75% of electrode. The NGK V's I mentioned are already at about 90% coverage. Plugs like copper Champion, I've see the ground strap go BEYOND the electrode by as much as a 1/4" in the past. Most extend by at least 1/16"- none of which helps the engine run better.

 

Any questions, just ask. Slipping the cardboard between the gap will also help keep shavings off the ceramic. Remember to clean/blow off before installing. Also, any ridges on the bottom-side of the groundstrap that occur from the filing, need to be knocked down. You can do this when gapping the plug as it'll clean that off. It's worth the the 5 minute per plug time to try. Do NOT bend the ground strap or weaken it by constantly regapping and closing. Yes this will help and work on turbo'd cars. Running 91 octane will net best results, but 87-89 is fine too. Post your results as I'd like to hear your reaction.

Edited November 16, 2014 by Bushwick

[TKFlight]

Very interesting. I'm ordering the plugs and wires shortly and will post back with the results.

[Bushwick]

One other thing, this compliments a freer flowing exhaust and intake design nicely.

[bluedotsnow]

man love the mod but please make a better video it was so low quality on my end that I couldn't really see any difference in the ground strap. I plan on doing this but I'm going to use a dremel tool and a vice with a piece of tin guarding the electrode.

 

I was wondering if there was any real reason why my car seemed to run better on iriduim plugs now I know

[Bushwick]

Sorry on quality as it was don'e quickly on the phone. Other camera isn't much better. I upconverted and that was best it got. But gives you the idea on what needs done.

 

I wouldn't use a dremel. Stick with a mill file. The ground strap isn't hardened steel. You can knock a corner down with 5-6 strike with the file. From there, it's just blending the contour and evening out. Think of it as filing a fingernail. The same exposed area of the fingernail is what gets removed. Also, a dremel with a grindstone or even a sand drum will eat the material WAY too fast and will be very hard to control, and you'll still need to go back over it with a file or buffing wheel in the dremel to remove all the grind marks. The file keeps the surface smooth enough you don't need to rehit it. Most mileage I put on a set of modded plugs was 40k. They looked as if they were factory, even after all that time, but the electrode had normal wear. Don't want to leave deep scratches that can build up carbon deposits. If your plug's strap is the variety that hangs out 1/16" past the center of the electrode, just knock the flat edge down to the right length, then round the corners. G/L

 

 

EDIT: Careful how much pressure you apply with the file (especially in a vice) as you can force the ground strap into the electrode or close the gap beyond what it'd take to get the gapper in there. The 5-6 strikes to knock the edge off is with a new file and light pressure. Usually I'll hold plug in one hand, then file in other. Very easy filing work and the 5 minute I suggested is a first timer. Takes me 2-3 minutes a plug with the NGK V Power with the shorter strap.

 

 

But yeah, the other benefit is getting more from your normal style plugs for less money. I suppose if NGK and the like did this with their entry to mid level plugs, no one would buy the overpriced ones, unless they were looking for some sort of extra long life-span.

Edited November 16, 2014 by Bushwick

[OLsubedrivr]

Very cool, I remember that NOW, as an ol-school street racer, that was a trick the pro stock boys were doing. thanks for "jarring" my memory. Time for new plugs, just the past few days I am getting some of that " bogging" on my 04 Fox X, mostly in 1st & 2nd unless I keep the rpm's up and accelerate harder than usual. I'm gonna try the V grooves. THANKS agin!

[Bushwick]

You are welcome. Wish I had the old magazine still as the articles were priceless.  

[bluedotsnow]

I have ALOT of experience using a dremel tool, I use one to sharpen my chain saw.... bushwick you referenced caution on pressure with a file... a dremel does remove material quickly but requires little pressure.. so both methods have their pro's and con's if your new to rotery tools I would use a file but if you have ever used one to carve wood or stone for art sake its a good bet you have the skill... as for deep grooves I have many bits that include polishing bits so I could hone it smoother than factory, no need.... but....

 

cheers!

[spazomatic]

In catalogs like Jegs or Summit or probably lots of places on the net, you can find plug indexing washers. They're pretty handy for getting the plug pointed in the direction you want.

[Bushwick]

I have ALOT of experience using a dremel tool, I use one to sharpen my chain saw.... bushwick you referenced caution on pressure with a file... a dremel does remove material quickly but requires little pressure.. so both methods have their pro's and con's if your new to rotery tools I would use a file but if you have ever used one to carve wood or stone for art sake its a good bet you have the skill... as for deep grooves I have many bits that include polishing bits so I could hone it smoother than factory, no need.... but....

 

cheers!

 

 

I'm on my 2nd dremel after the 1st gave up after many years in a quick pop and release of smoke so it was retired and replaced with a unit that didn't have as much torque ;( Was just giving a heads-up as the material is soft. I'd suggest practicing 1st on your old plugs you are pulling and see if you terminate the overhang to stop around 75% of electrode coverage with a perfect radius blend where the square tip used to be. 

 

Also, try and keep the area getting rounded 100% vertically straight. It's possible to "cant" the edge, so the bottom edge closest to the electrode gap extends further than the top of the  

 |````\

 |___\  ( <- rounded edge with a canted angle)   

      |```|  (<- Electrode)

 

ground strap like so ^. Doing that might affect the incoming charge to get thrown a bit as it hits the ramping (speculation as I don't know where the incoming charge hits on these heads). If the air/gas enters the head on top of the that is. If someone where to take the strap back to to say beyond the middle 50% coverage point, to something like 25%, the angle might actually help if the incoming charge hits directly from above. Again, purely speculation and probably doesn't matter, but worth considering if you are the type to make up several sets of plugs, then run them back to back on a dyno to see if any hp/tq changes occur and if the mixture leans out  or the spark gets weaker or something in the higher revs. Furthest I ever tried was around 45% electrode coverage with the rake on my old 4.6L DOHC Ford. Don't think I'd go back to that short considering the NGK V's are responding so well as-is.

 

 

Anyone tried this yet? Would love to hear your impressions. Only person I ever had try this was a Harley owner and he really liked it. His reaction to me was funny as he was skeptical at first

 

 

This is smarter:

 

 `````|

 ___|

     |``|

Edited November 19, 2014 by Bushwick

[Bushwick]

Has anyone tried this with their car yet? Hoping to hear how your car's fared with the better spark and less hesitation

[Aluxes]

Im gonna give this a go. Also considering that I have the MSD coil mod and Magnecor wires I may get better than average results. It wont be till this weekend though.

Thanks for the tip on this easy mod Bushwick!!

[uniberp]

_{I notice that my car runs better, gets better gas mileage, and is quieter and smoother after I wash it.}

Edited December 10, 2014 by uniberp

[CNY_Dave]

_{I notice that my car runs better, gets better gas mileage, and is quieter and smoother after I wash it.}

 

Stone the unbeliever!

[Fairtax4me]

I still have intentions to try this but, have had too much school work and other stuff to deal with. Car ate a wheel bearing over the weekend. No noise Friday night when I drove home. Drive to the store on Saturday and it was fine going there. Leaving the store it starts growling. By the time I got home (3 miles) it was starting to grind the brake rotor on the caliper bracket. No noise at all, to 1/4" of wobble in 5 miles. I've never had that happen on any car.

 

My 96 isn't road legal because of the exhaust falling apart, which I also have not had time to fix. So I'm in the GFs 95 that's been castrated to 2wd because of a bad u-joint.

 

So MAYBE next weekend, after finals, weather permitting.

Edited December 10, 2014 by Fairtax4me

[Bushwick]

Im gonna give this a go. Also considering that I have the MSD coil mod and Magnecor wires I may get better than average results. It wont be till this weekend though.

Thanks for the tip on this easy mod Bushwick!!

 

Can you do us a favor? Try timing a 0 to 60 before and after on the same stretch of level road. I suggest running premium 93 or at least 91, and say a 1/3 of a tank of gas, while leaving everything in/on the car exactly the same before/after so the results aren't artificially altered. If you have a camera, try setting it on the top of the steering column so it records the speedo and tach, as that'll be the most accurate way to compare the speeds against an online stopwatch, which is more accurate than a video player's time. Would love to see what the measured difference is. Never dawned on me to try that before as I already it made a difference, but in lieu of a dyno, it's the the next best way to pop the finger at the disbelievers

 

_{I notice that my car runs better, gets better gas mileage, and is quieter and smoother after I wash it.}

 

This "mod" is tried and true, and it's been around for 40-50+ years. 

 

I still have intentions to try this but, have had too much school work and other stuff to deal with. Car ate a wheel bearing over the weekend. No noise Friday night when I drove home. Drive to the store on Saturday and it was fine going there. Leaving the store it starts growling. By the time I got home (3 miles) it was starting to grind the brake rotor on the caliper bracket. No noise at all, to 1/4" of wobble in 5 miles. I've never had that happen on any car.

 

My 96 isn't road legal because of the exhaust falling apart, which I also have not had time to fix. So I'm in the GFs 95 that's been castrated to 2wd because of a bad u-joint.

 

So MAYBE next weekend, after finals, weather permitting.

 

I've never heard of a wheel bearing going out like that either. Usually bearings go out rather slowly, and give plenty of notice they are giving up the ghost.

[CNY_Dave]

My opinion- the mod will help a higher-compression engine, but if in general it gave mnore power and better mileage cars would come with plugs shaped like that.

 

Any car company would love to bolt in a mileage improver.

[Bushwick]

The cheaper NGK and other plugs have already shortened the length of the grounding strap over some other brands (Champion comes to mind). Judging by the crude marks to cut the straps to fix them against the threading, they aren't putting the money into anything but a square tip, which isn't ideal for air flow and the spark has more area to deviate on. Also, plugs might be forced to keep costs down in production and might have to consider an emission impact.

 

Anyways, like I said, it's already been proven so I'm not going to waste the time defending it.

Edited December 12, 2014 by Bushwick

[Bushwick]

I was skimming through a Mustang forum on plug issues on blower cars and found this: 

 

 

I can't quite tell, but it looks like It might be a modded plug as the top corners were half-assed and rounded slightly. This is TOO far to bring the ground strap back! As you can see, there is arc scorching on the side of the electrode which needs to be more in the center of the top of the electrode. The particular plug was apparently pulled from an older V8 Mustang running pump gas and too lean with a blower.

 

Either way, I posted the link to the pic as it shows how the ground strap's position can alter where the spark hits (all those little dots are where the spark was moving to, and some are pretty far out there!), and obviously that plug's ground strap is just too far gone. Conversely, it also shows what happens when the ground strap is too long, (ideally you want a straight up 12 and 6 o'clock spark; if the arc is forced to the 1 or 2 o'clock position, it'll slow the combustion event x 4 cylinders as it has to reach out further), it'll arc against the strap at different positions randomly or "wander" more, as well as the delay from the mixture having to move around the ground strap. Talking minuscule time delays, but the HP freed up and the quicker rev response is the reward and very noticeable from a before/after. Engine also sounds smoother and stronger when revving. 

 

Also, if anyone wants to try this plug mod (correctly that is) on their car but isn't comfortable filing the ground strap, PM me and let me know. If you buy the plugs and pay for round-trip shipping, I'll file them back for you and round the edges correctly, and gap them too, then ship back no labor charge. Once you have them, I suggest practicing on your old ones with mine in hand to compare and keep the one that comes out the best. In 40-60k miles when the time comes to replace again, you'll be able to use it as a reference

Edited December 16, 2014 by Bushwick

[Aluxes]

Can you do us a favor? Try timing a 0 to 60 before and after on the same stretch of level road. I suggest running premium 93 or at least 91, and say a 1/3 of a tank of gas, while leaving everything in/on the car exactly the same before/after so the results aren't artificially altered. If you have a camera, try setting it on the top of the steering column so it records the speedo and tach, as that'll be the most accurate way to compare the speeds against an online stopwatch, which is more accurate than a video player's time. Would love to see what the measured difference is. Never dawned on me to try that before as I already it made a difference, but in lieu of a dyno, it's the the next best way to pop the finger at the disbelievers

I didnt get to it this weekend, too many other car things took up my time. Ill be out of town for the next two weeks, but will try to get to it after. Sounds fun!

[CNY_Dave]

As an aside-

The spark will jump wherever the gap is 'electrically' shortest.

Electric fields/charges are greater at sharp corners.

 

Of course in that case the corner was the shortest distance...

[Bushwick]

As an aside-

The spark will jump wherever the gap is 'electrically' shortest.

Electric fields/charges are greater at sharp corners.

 

Of course in that case the corner was the shortest distance...

 

By "greater", do you mean more intense? Or do you mean more focused? Judging by those scorches, I'm assuming more intense as the top of the electrode never seems to get those scorches, which might have some sort of short term benefit with a more intense spark. But then again, the actual ignition coil wasn't referenced with the pic, so it's possible the person was running some really high voltage coil. Either way, if the really far out arc spots aren't painfully clear, if that occurred at high rpm, it'd probably register as an engine miss as the combustion timing would have been slowed.

 

I wonder what would happen if they made electrode longer and added a 90 degree "L" bend so it's tip was facing the edge of the ground strap? So it'd be more like a "bridge arc"? The incoming charge mixture would hit the spark head-on.

 

Oh well. Would love to see a modern 4, 6, and 8 cylinder on a dyno after the mod. The more pistons, the better the HP bump, but it'd be nice to have a modern graph visual to show how spark can affect the way an engine responds. With the advent of turbo'd 4's and less than stellar aftermarket support for true mechanical HP adders like better heads, cams, etc. in favor of just adding a bigger turbo, all these old "tricks" for making a few extra HP/TQ are disappearing, which is a real shame.

[mikaleda]

This reminds me of the E3 spark plugs I used to see in racing magazines. They were short lived for a reason, all they are doing is giving you a slightly hotter spark and its not going to give you any noticable increase in horsepower. You could get alot more horsepower by disconecting your ac and power steering pump.

[Bushwick]

This reminds me of the E3 spark plugs I used to see in racing magazines. They were short lived for a reason, all they are doing is giving you a slightly hotter spark and its not going to give you any noticable increase in horsepower. You could get alot more horsepower by disconecting your ac and power steering pump.

 

Those E3 are pretty bulky and with all that metal being forced into the combustion chamber, it probably artificially bumped the compression ration slightly. I always thought those were too gimmicky tbh and too pricey.

 

The actual modding I laid out (obviously NOT the pic above if that's what you were thinking) takes 15-20 minutes and you get better MPG, eliminates hesitation, and few HP are freed up. That's NOT gimmicky. It works, has worked for ages, and will work for those that actually try it rather than bash it w/o trying for themselves.