Spark plugs.......

[Karl]

The word is:

Hard, cold fact: Bosch has discontinued manufacturing ALL Non resistor automotive spark plugs this spring. Whatever stocks are out there are only what's available until they're GONE. Airhead Parts has recently bought up as much of the Non-Resistor Spark Plugs as they could find and I'm sure outfits like Bug City and other are doing the same as the word trickles down from the warehouses. After that, it's resistor spark plugs from Bosch.

NGK still continues to market Non-Resistor Spark Plugs, but word from my sources is that these will be discontinued at the manufacturer sometime soon as well.

[skills@eurocarsplus]

the shop i work at deals with wordpac, save and some other wholesale companys. i will ask my rep's tomorrow if they have heard this. i find it a bit hard to believe, based on the fact that there are so may applications that don't require a resistor plug. but who know's.......

[djspn]

What's the downside of using resistor plugs in our buses?
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Peace
'71 Bus .....stock running gear [ex SVDA and pertronix]

[regis101]

Thinking the same about all that resistance.
There's resistance in the rotor, wires, and connectors. Now the plugs?

I just pulled out my first set of Autolites. They look good with little or no wear of the electrode. They probably have ~7k miles on them. These were cross referenced with the w8cc, IIRC.

I pulled them to put in a set of w7cc's in my stash since we're doing some extended highway driving for a weeks vacation.

I'm wondering if a VOM will tell how much difference from the older w8's to the new Bosch line up.

Main question is , Why the switch?
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Peace, Regis

[regis101]

I just checked a used w8cc from the stash. As thought it shows a dead short at the electrode. I have some of the new wr8cc's. They show ~6k ohms of resistance.

I don't know what a stock rotor reads because I don't have one. The bentley should have this info.

On the bright side, If the stock rotors are around 6k, then a modified rotor from AC.net will, (should would be conservative), bring the total resistance down to what we know.

Just some thoughts. I'm open for correction

Again, Why'd they change?
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Peace, Regis

[Wildthings]

The switch is probably due to low demand, but I can't say for sure. Many cars for decades have run both resister wires and resister plugs. There may be a down side there might not. Plugs have definitely improved over time in general. They last longer and take less voltage to fire so your points last longer. If running resister plugs gives problems we will surely hear about it soon enough.

[mygreenbus]

I also see that the Bosch WR8AP crosses with the W8AC.
From NGK:
Frequently Asked Questions

Q: When should I use a resistor spark plug?

A: NGK "R" or resistor spark plugs use a 5k ohm ceramic resistor in the spark plug to suppress ignition noise generated during sparking.

NGK strongly recommends using resistor spark plugs in any vehicle that uses on-board computer systems to monitor or control engine performance. This is because resistor spark plugs reduce electromagnetic interference with on-board electronics.

They are also recommended on any vehicle that has other on-board electronic systems such as engine-management computers, two-way radios, GPS systems, depth finders or whenever recommended by the manufacturer.

In fact, using a non-resistor plug in certain applications can actually cause the engine to suffer undesirable side effects such as an erratic idle, high-rpm misfire, engine run-on, power drop off at certain rpm levels and abnormal combustion.

From nology.com
Question:
So non-resistor spark plugs are better for performance?


Answer:
Yes. If you are looking for performance you want to use non-resistor spark plugs. A resistor is exactly what the word implies. When the spark crosses the point of resistance some of the spark energy is lost. A resistor is like an electronic obstacle and could be the cause for a weak spark. Non-resistor spark plugs deliver a more powerful spark.
Back To Top


--------------------------------------------------------------------------------

Question:
Why do car manufacturers recommend resistor spark plugs?


Answer:
One reasons is actually emissions. Since the resistor is an obstacle it forces the spark voltage to be higher, assuring combustion in a lean mixture. Also resistor plugs are MUCH cheaper to produce. You will never find resistor plugs in serious race cars, yet these cars use some of the most sophisticated engine management and data acquisition systems. But these cars have no EMI problems. Why? The spark happens inside the combustion chamber where he is completely shielded by the metal cylinder head. No EMI can escape the combustion chamber.
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Bosch probably just doesn't sell enough non-resistors to make it worth their while. I alwasy ran resistor plugs in my '60's American muscle cars to no detriment, I would think the guys looking for "performance" are mostly racers who are adding power incrementally.
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'72 Bus

[rneithammer]

Just applying a little basic electrical engineering (it's what I've done for a living for the past 30+ years) to this:

Figuring that coil primary current is about 10 amps, at 12V, that's 10 X 12 = 120 watts of coil primary power. The coil is a transformer, so power on the primary side is the same as power on the secondary (i.e., high voltage) side (except for losses, which are small and can be reasonably ignored). Figuring that secondary voltage is about 20,000 V, the current on the coil secondary (which is the current that flows through the spark plug) is 120 / 20,000 = 0.006 amperes. The amount of power lost in the 6 K (6000 ohm) resistor plug is 0.006 squared X 6000 = 0.216 watts. So, using resistor plugs instead of non-resistor plugs means I loose 0.216 watts of my total 120 watts of ignition coil power in the plug's resistance. That is about 0.18% of my available ignition power - not enough to worry about.

I say "fugetaboutit".

[busman78]

Bosch announced the non resister phase out around April of 2007, although it was not overly publicized. Buy them while you can!

[Wildthings]

[rneithammer]

Wild: Like I said, "Basic". And, I agree with everything you've said. My intuition tells me that added resistance, no matter whether it's on the primary of secondary, would push the circuit's dynamic response in the overdamped direction, thus faster spark decay, if anything. Also agree that actual testing results could be surprising.

I with you, I think that 6K of sparkplug resistance would not matter much in the face of megaohms of sparkplug gap and points gap resistance, so, I don't see how using resistor plugs makes any significant difference.

[PicklePickle]

I run WR8CC plugs in my 78. I have to clean carbon deposits off of them more often than I like. I suspect that having the non resistor plugs may alleviate that problem (at least some)--I'll know soon as I plan on changing them this coming week to W8CCs.

On a side note: I notice that some people switch back and forth between the W8 and W7 series. Why is that?
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"Aircooled VWs are like roaches in that if you let one in, they'll soon be nesting all around you in great numbers."
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1970 Yellow Beetle aka "Melbourne"

[phip]

http://www.ratwell.com/technical/FAQ/FAQContent.html#0144

Check out in FAQ Sections 1.44 and 1.45. Basically the W7CC runs a little cooler than the W8CC and so is recommended when the temperature is consistently over (25 C / 77 F).

[PicklePickle]

[regis101]

The system already has resistance built into the rotor, wires and plug connectors. Now we're gonna place more resistance with the new plugs.

Doesn't seem right.

Back in the day some US cars had a radio filter to eliminate the static from the ignition system.

VW did the same with the above mentioned items. So it seems that no coordination was met.

In theroy, I'm trying to eliminate the resistance for the cleanest path to the tip of the electrode at the brink of radio static. No radio? Use the iPod?
Get rid of all the built in resistance you can.
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Peace, Regis

[regis101]

Holy shiza. Did I say that.

Searched around for spark plugs. Came across this thread. I'm still of the opinion that the Bosch/VW ignition components for our use has enough resistance already built in. Don't need any more. Ratwells site has some good pictures/charts about the burn time etc with stock vs modified ignitions.

How to combat? Use one of AC/net's modified rotors. Use aftermarket wires
Find another source of non-resistor plugs.

So with this thought, The only ones I've found are champion N11YC. Maybe there are others?
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Peace, Regis

[SGKent]

I bought a whole lifetime supply on Ebay of NOS Japanese NGK really cheaply (we decided on NGK after reading the articles here and on RAtwell. You might try there. Some places still have the NGK - sparkplugs . com or something like that had both the Bosch and NGK about 2 months ago.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[SGKent]

I might add. The current flow of a spark plug is neglible. The resistance in the plug changes the spark timing slightly and also reduces the current just a little. That reduction in current results in less RF being produced. If that change affects your performance, it is either perceived or you have some other issues going on.

from Denso FAQ

"Q. Does the standard resistor have effect on the required voltage?

A. About 99% of today’s cars are equipped with resistor spark plugs. Most of the standard spark plugs and all the longlife and iridium power spark plugs have a built in resistor of 5k Ohm. This has no effect on the available voltage at the spark plug. Often people fear the word resistor because it makes them think the voltage and current is limited. The resistor that is fitted in the spark plug is 5k Ohm. This is nothing compared to the resistance of the air or the air/fuel mixture in an engine. There is no measurable effect on performance. The resistor is necessary to prevent problems with engine management systems, cellular telephones and datalogging equipment. The spark plug is the best place to put the resistor, because this is the closest you can get to the spark itself. The resistor value of a resistor spark plug and resistor leads and caps is less than 0.01% of the total resistor value of the air/fuel mixture inside the engine."
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[regis101]

Yeah. But one has to view the source. The required resistor plugs are part of ( today's) design that has little resistance elsewhere in the system. VW designed (our 30 yr old ) components with resistance built into them. The rotor has it. The wires have it. The bakelite connectors have it. All for the very same reason as the modern cars and their catch all phrase, "cars need resistor plugs".

The point is, if the VW Bus required resistor plugs , ALSO, they would've spec'd them. Back in the day, a radio filter was attached to distributor to ward off the noise. Until I was schooled on Bosch VW rotors, i never would of thought of a resistor in the thing. What the..?

I can't accept added resistance for a , Just because, answer. If someone was to swap them out as I slept, I would be none the wiser. But given the choice, I'd like to keep things normal. Adding resistance is like lowering compression.
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Peace, Regis

[regis101]

Anyway, I tried the NGK's. I ..don't..seem.. to like the way they wanted to screw into the head. Kinda like the pitch was off or something. Pulled it out to retry the used Bosch. It screwed in with fingers until seated. Maybe the Bosch plug kinda rethreaded the head, dunno.

I think i tried Champions in the past. Can't remember if I liked them or not.
As previously mentioned, the N11YC's are non-resistor.

Tried Autolite 405's with good success. I remember checking them with a VOM and finding no resistance. An internet site gave the Autolite 405 a resistor rating. Fired off an email. No response. After some miles, the Autolite electrode tip(s) were still square.

And the band played on...
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Peace, Regis