Best plugs for a 2110 Stroker, mild cam, dual Dell 40's Magnaspark ignition system?
NGK 7912 D7EA ?
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In my 2110 I use NGK 7512 Standard Spark Plug - D6EA.
I have 12mm plugs also, but use NGK DP8EA9(now I use DPR which is the same thing except resistor). The P is a projected insulator, gets the tip a bit further into the combustion chamber, ground electrode is longer too.
Most aircooled engines use a 6-8 heat range, lower number is hotter for NGK.
Here's a link to the NGK chart so you know what you've got or are ordering:
Señor @Panhandle Bob
From my service manual (What? You think I can remember all this stuff??) Remember that I also have a 2,110 with a MagnaSpark II
The spark plugs are NGK B6HS, recommended by BOTH Dave Hoagland at Blackline Racing and Pat Downs at CB Performance. They are ½” reach threads. The Magna-Spark recommended plug gap is .032” These are not RFI resistance plugs because the plug wires are RFI resistant, instead.
What would be the best NGK replacement plug for the Bosch WR8AC +Super that is no longer available. My engine is a 1600cc, with a Compufire electronic ignition and EMPI dual HPMX.
Thank you, Michael
Bob - Found this by accident when I was setting up a facetime call with the kids and thought you could use the info:
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@Gordon Nichols You found it by accident? This link was posted in my response above.
Must be popular..... I spotted it in my iPad photos from God-knows-when in the past.
Didn't even look at your link til now, so great minds think alike! 
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Just a quick tutorial in case you were asleep in shop class, had a teacher who didn't know in shop class, never took shop class, or went to shop class 5 decades ago, and the information is rattling around somewhere in the bottom of your RAM bucket with the winner of the 1973 Super-Bowl, how to figure the area of a rhombus, and the name of your 3rd grade crush.
Choosing a spark-plug for a modified Type 1 is not a matter of universal "recommendations" or specs you'll find in a book. The heads can be cut for a lot of different spark-plug threads, which means you need to know what you've got before you can do anything else. Most modern aftermarket heads (and all CBP heads, if I'm not mistaken) are cut for 12 mm long-reach plugs. That gets you in the "D" family in NGK, but older performance and stock VW heads are generally cut for a different plug (14mm, or "B"), so pay attention to what came out and try to make sure it was right to start with.
The length of the threads, and the type of seal (is it a taper or a crush gasket?) is also important, and a part of the chart above.
There's the matter of the tip of the plug, which Danny touched on above. Everybody's got a different take on what's best - but generally the plug you take out will probably be a standard tip. Projected tips (as @DannyP referred to) get the tip of the plug further into the head, which puts the spark closer to the center of the chamber, which is a nice thing. There are a couple of reasons everybody down't automatically do this, but if you can, the pros definitely outweigh the cons in giving this a try. Just make sure it doesn't hit anything inside the chamber - rotate the engine a few times by hand and take the plugs out to see if they are being "kissed" if you're unsure.
Then you need to decide if you want resistor plugs or not. I've pretty much always run resistor everything, but I'm rethinking that. Resistor plugs and wires cut down on RFI (that's "Radio Frequency Interference"), so you can listen to the radio without a buzzing that rises and falls with RPM. I'm unsure how RFI interferes with MS or Speedunino modules if you go with EFI, but a standard ignition is unaffected by it. Resistor stuff greatly diminishes the electrical energy delivered at the spark-plug, and that's why I'm rethinking it. Non-resistor plugs and wires (if you can even find them since Taylor went out of business) connected to a new-style coil and a CDI box deliver crazy spark, which is a good thing.
So, in the preceding paragraph on resistor or not, I answered nothing. Here's the short answer: when in doubt, resistor is the safe bet. If you want a bigger, fatter spark, those resistor components are doing you no favors.
Which gets us to the least understood and most important part of spark-plug selection: the heat range. Every chart everywhere has different numbers going from "colder" to "hotter". Most American and German plugs numerical designation gets bigger as the plugs get hotter, but NGK and Denso get smaller as they get hotter. So a DR7EA (a super-common plug) is hotter than a DR9EA.
So what exactly does "hotter" and "colder" mean? It makes sense that you have a "hot" engine, and you'd like "hot" plugs, yeah? The very name of it ("hot") seems to indicate that a hotter plug delivers a more robust spark.
Actually, no. A "hotter" plug doesn't have a bigger spark, and is not necessarily a better thing, especially not in an air-cooled engine. Actually, in my opinion, you want the coldest plugs (that won't foul) that you can get away with. The heat range indicates how long the plug tip stays hot after the spark. The purpose of this heat is to burn off any unburned fuel or carbon that might be inclined to build up on the tip, so that by the next spark-cycle, the plug is clean and ready to fire. But an overly hot plug is a hot-spot in the combustion chamber, a glow-plug if you will, ready to pre-ignite the mixture in a chamber that is already hotter than optimal (due to the fact that is isn't cooled nearly as efficiently as a conventional water pumper). Increased compression only increases the tendency to pre-ignite, so that glowing little cigarette tip ready to give you an uncontrolled explosion is about the worst thing that can happen.
Pre-ignition is no bueno. It's one of the reasons most engines are built with about a full point less compression than would be optimal. That ACVWs run hotter than optimal, and that Speedsters in particular have horrible airflow management making a hot-running engine even hotter only adds to the problem.
So yeah, if you have an 8:1 1776 with a W120 cam, then running a DR6EA plug is probably not going to hurt anything. But if you are running something more unconventional (say, a twin-plug 11.7:1 2276 with a FK7), you'll want plugs more in the NGK "8" or "9" heat-range. A "normal" 9:1 2110 with a W120 will be happy in the "7" heat range, but I run mine with 8s. NGK plugs go up to the "9" heat range before you get into the more exotic racing plugs with pricetags many times that of a standard DR7EA.
You may need to get several sets of plugs and do this a couple of times before you arrive at "optimal". Or maybe being "optimal" - and anal - is not your goal (I'm looking at you, @MusbJim) - in that case, just start with a resistor plug in the "7" heat range and buy your motor oil on sale.
Of course, any time you change anything else (hotter coil, going to non-resistor wires or plugs, adding a CDI box, going to crank-fire), you'll need to start over to be optimized - and if you are doing this kind of stuff at all, you care about being optimized.
Keep in mind that this is all part of the Madness - and that we're all just prisoners here, of our own device. Welcome to the PCCA:
The "Plastic Clown-Car Cult of America"
Great tutorial, Professor.
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Than you all!
Now, about engine oil........just kidding!
Yeah, that is GOOD stuff.
RE: Speeduino
I haven't tried non-resistor plugs, but from what others discovered on the Speeduino forum, RESISTOR PLUGS ARE RECOMMENDED. Some guys had some electrical interference issues with crank and/or cam VR or Hall sensors. So I just chose to go resistor plugs and wires off my VW Golf coilpak. I've had no issues at all.
Voltage is much higher, as is dwell time(half as many sparks per revolution as a coil/distributor) so the resistor elements aren't hurting you for spark delivered.
I never thought there was 15 paragraphs worth of things to talk about regarding spark-plugs... but I (apparently) like to hear myself talk.
... and there's a LOT more I don't understand that what I do. The question of the moment is whether or not I can use solid-core wires and non-resistor plugs with MegaSquirt.
@DannyP? @Michael Pickett? @LI-Rick?
So much to learn. I feel like I'm running out of time.
When did Taylor go out of business? CB Performance still shows their wires.
I have Magnaspark II wires (without Magnaspark). I believe they are resistance wires.
I have always thought one didn't need both resistance wires and resistance plugs.
Great summary, Stan. Ditto on what Danny says above about EFI interference from non-resistor setups. I run both resistor plugs and wires and a hot coil.
For comparison sake, I run NGKs in the "7" range in my 9:1 compression 1776 and they are closer to being too hot than to being exactly right.
@Stan Galat posted:The question of the moment is whether or not I can use solid-core wires and non-resistor plugs with MegaSquirt?
I think you'll have interference problems on your crank position sensor with no resistors between the coil and the plug tip. Just like fiddling with the rabbit ears on our childhood TVs, it depends on a lot of situation specific variables (coil location, wire routing, effectiveness of shielding on your crank/cam position sensor(s) wiring, Hall effect sensors vs inductance sensors, location and shielding of the Megasquirt box, etc.
I've ended up being very conservative (imagine that) on keeping the sensor data as noise free as possible and still end up with a medium level of signal filtering at the software level to fully avoid any sync losses (Speeduino). I had similar experiences when I was using Megasquirt units on the turbo.
My conservative approach: hot coil, resistor wires & plugs, Hall effect sensors (stronger signal at the source), properly shielded & grounded signal cables and distant (inside driving compartment) location of the ECU.
The sensor signals are the heartbeat of an ECU. If you give up anything on spark (and I don't think you will), you'll get it back in spades on accuracy and tunability.
Good luck!
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Stan, it looks like you learned more in auto shop than I did in half the college classes I took. In the 50 years since, there have been relatively few situations where I needed to know Avogadro's number.
After my engine was a few years old, I decided to put in new plugs because, well, the plugs must have been a few years old by then, too, so maybe they had gotten puffy or moldy or something. The old ones that came out looked about the same as the new ones I put in, but changing plugs is something guys do to feel more like guys.
I got the same plugs the engine builder put in because I figured he would know, right?
One thing I did learn over the years, though, is that you should check the gap on new out-of-the-box plugs. It's another thing that makes you feel more like a guy.
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Most of the time, plugs right out of the box can be all over the place with gaps. So you both "feel like a guy" and make sure they're right before you put them in. And if you have a Magna-Spark or a "hotter coil" (over 40K volts) you can run a slightly wider plug gap. I was running platinum tipped plugs in Pearl for years from my snow-mobile days and only changed to regular plugs because two people I trust (a.) told me to and (b.) they had no experience with platinum-tipped plugs in VWs. I thought the Platinums were great.
Many after-market VW distributor rotors are resistor rotors. In fact, I had to look a while to find a non-resistor rotor. If you look at the top of the rotor and there is a solid metal strip going from the center of the rotor top to the end that rotates around it is a non-resistor rotor. But not always - The seller should tell you if it is a resistor type or not. Most of those at Aaircooled.net look the same, but they tell you which is which.
EFI coils (like the Magna-Spark I and II and a few others like the "hot" MSD) can blow that rotor resistor out and you'll be dead on the side of the road.
So, the rule of thumb I've always used on non-computer-controlled cars is; Straight-through rotor, not a resistor type, with Resistor plug wires (so-called "Spiral Wound) and non-resistor plugs. If you have resistor/low-noise plug wires you probably don't need resistor plugs.
OTOH, if you have resistor plugs then you probably don't need resistor wires or rotor.
On the other, other hand - If you're running one-a those fancy-schmancy, E-Lec-Tronic engine control systems with lots of little transistatators in 'em, I would probably resistor the heck out of everything and use grounded metal shielding (boxes) for the computer-y stuff and run external wires through grounded metal conduits. Overkill, maybe, but it should work.
I don't get RFI noise on either FM/CD/Bluetooth with just resistor wires and the MagnaSpark module seems to be OK, too, and that's the extent of transistors in the engine compartment.
DO NOT RUN CONDUIT in a car, please. You'll create a massive antenna and ground loop at the same time.
IF YOU USE SHIELDED cabling for a VR(variable reluctance) crank pickup:
The shield is grounded ONLY at one end, which should be the ECU end of the wire. All grounds should go to the same point. My relays and ECU are grounded at the same point, the crank sensor shield is grounded at the ECU(the ECU has a half-dozen pins connected together on the board, as a ground buss).
On the other end, the shield is carried as far to the sensor as is possible, but left unterminated at the far end. VR plus, VR minus, and shield are all carried through the 3 pin Deutsch connector.
And about spark plugs: the last number of NGK plugs is the gap, and I've found them to be right on the money so far in about 6 sets. I use -9(DPR8EA9), which is 0.035" but open them to 0.040" to 0.044" due to the coilpack I'm using.
@Michael McKelvey posted:When did Taylor go out of business? CB Performance still shows their wires.
2/26/21 - acquired by PerTonix.
I assume the Taylor wires still for sale are leftover NOS.
It looks like Pertronics is selling wires under the Taylor name.
"...or maybe being 'optimal' - and anal - is not your goal (I'm looking at you, @MusbJim)" - @Stan Galat
Thanks for the 'props', my brutha! 
You lost me at "tutorial"...
I have NO idea what spark plugs I'm running in my Speedster....I just keep driving it! 
I thank all that have contributed. This is a wealth of information. I had recalled years ago many of you mentioning its best to know the correct plug reach or else the plug will hit the piston head and its all over.
Thank you very much, again.
Michael
@MusbJim posted:"...or maybe being 'optimal' - and anal - is not your goal (I'm looking at you, @MusbJim)" - @Stan Galat
Thanks for the 'props', my brutha!
I have NO idea what spark plugs I'm running in my Speedster....I just keep driving it!
Jim, I looked up "cool" on wikipedia and they had your picture.
I thank all that have contributed. This is a wealth of information. I had recalled years ago many of you mentioning its best to know the correct plug reach or else the plug will hit the piston head and its all over.
Thank you very much, again.
Michael
That's not a very likely occurrence in a VW. Flat-top pistons and a well-recessed plug between the valves usually leaves ample clearance for the plug tip. Unless you're running something like 11.5:1 and a VERY small chamber I wouldn't fret about it.
Stock heads are 14mm thread and 1/2" reach, most aftermarket/modified heads are different. These latter heads either have more material cast in or welded to make them 12mm and 3/4" reach. I certainly wouldn't recommend a 3/4" reach in a 1/2" reach head though. Then you can get either a painful and expensive metal-on-metal collision, or a hot-spot on the exposed threads. This is not good: detonation usually results, and even it doesn't you'll get carbon on the extra threads that can strip the head when the plug is screwed out.