D7EA vs D8EA - What's the Right Plug?

[k]

I see both these plugs mentioned and used. What's the right plug?

 

[The Mighty Gryphon]

D7EA is the specified plug.  D8EA is the same plug but one heat range cooler. 

Heat range has a lot of strange ideas around it.  There are people who swear that a cooler plug will make your engine run cooler and a smaller group who will swear the opposite.

What heat range means is how fast the heat the combustion process puts into the electrodes is carried away to the surrounding engine and ultimately into the circulating coolant. 

The only things the heat range actually affects are:

Plug fouling.  A hotter plug does a better job of burning the carbon deposits from incomplete combustion or oil consumption.  If a plug is fouling going to a hotter heat range can help it run cleaner.

Preignition/engine knock.  A hot plug can result in the electrodes being so hot that the fuel charge is ignited by them instead of the spark.  In extreme cases serious engine damage can occur.  A cooler plug can reduce the electrode temperature to the point where preignition won't be a problem.

Accelerated electrode erosion.  High electrode temperatures can wear away the electrodes causing erratic spark operation and misfiring.  A cooler plug may help extend electrode life.

I run all my bikes with D7 plugs.  I have had no problem with preignition or plug life, plug reading show clean running.  I ride in a wide ambient temperature range up to as high as 115F at speeds of 75-80mph. 

As far as the cooler D8 range goes, I've not heard it recommended for stock bikes.  Perhaps there are aftermarket "performance" chips or exhaust systems that specify that range to accommodate a different stage of engine tuning.

One important point to remember about heat range is that each plug manufacturer has their own numbering system.  A 7 in an NGK is NOT the same as a 7 from Bosch or AC.

Plug trivia:  Champion and AC were both started by the same guy.  AC are Albert Champion's initials.

[k]

Thanks for the awesome answer. Somewhere way back, I got the idea that D8EA was the right plug, so I installed them in my 1985 K100, to absolutely no perceived ill effects. I've been running D8EAs for years, in two different Ks. I have four D7EAs around here. I'm wondering if it's worth the trouble to install them. It doesn't sound like I can expect much in the way of performance gains.

 

[The Mighty Gryphon]

Just save them for your next plug change. 

[k]

That's funny.

I'd have to remember when I installed the current plugs to know when I should change them. 2006? 2007?

[Chaos]

That's funny.

I'd have to remember when I installed the current plugs to know when I should change them. 2006? 2007?

I had a set of Beru RO-002's in for at least 3 presidents :eek: Finally changed them on general principles and put in Bosch or NGK's or something, hell, they've probably been in as long :mbird

[technostructural]

I've been running D7EAs for a while now with no issues.

They work a lot better than the fouled OEM ones I removed!

[beemrdon]

The NGK DR7EA plugs that I bought didn't have the end caps on them.  I had to call NGK and they mailed me 4 caps and told me to buy the "B" plugs.
The NGK DR7EB plugs already have the end caps installed, otherwise the same.

https://www.amazon.com/NGK-5469-DR7EB-Standard-Spark/dp/B009B43FQ2

[k]

Continuing the research into K spark plugs, today I swapped my plugs, and to my surprise, I pulled DR8EIX plugs out of my 1985 K100. Obviously, I thought this was a good idea some point in the past.

Nice plug, to be certain, but it's a resistor plug in a bike that doesn't take resistor plugs. It ran fine on these plugs, for years.

http://www.motorcycle-superstore.com/18646/i/ngk-dr8eix---iridium-spark-plug

Explain.

[Laitch]

Explain.

The resistor in the plug is to prevent interference with electronics, not to change performance in the combustion chamber. Stock, your bike had resistor cables and caps, already. Maybe your plugs were on sale. Iridium is an attractive word to many people. Maybe they were bought to match somebody's sunglass lenses.

[Chaos]

does resistance plus resistance hurt the revolutions?

[Laitch]

does resistance plus resistance hurt the revolutions?

Depends on whether it's anti-resistance resistance or pro-resistance resistance.

[Chaos]

Anti resistance is status quo.  not revolutionary at all.

[Shel]

The NGK DR7EA plugs that I bought didn't have the end caps on them.  I had to call NGK and they mailed me 4 caps and told me to buy the "B" plugs.
The NGK DR7EB plugs already have the end caps installed, otherwise the same.

https://www.amazon.com/NGK-5469-DR7EB-Standard-Spark/dp/B009B43FQ2

Searching these forums for 'NGK-5469',  beemrdon's post above was the only result that came up.  A cross-reference I came across matched it to the NGK DR7EB that The Mighty Gryphon recommended in his old post here.

I've found 4 sources for the NGK-5469 including NGK's website.  But the prices and photos vary pretty radically.  Can anyone confirm these are all the same plug?

NGK 5469 DR7EB Standard Plug $1.99
https://www.ngk.com/product.aspx?zpid=9740http://

NGK 5469 DR7EB Standard Spark Plug $14.83
https://www.amazon.com/NGK-5469-DR7EB-Standard-Spark/dp/B009B43FQ2

NGK Spark Plug  Part #5469 $1.69
https://www.oreillyauto.com/detail/ngk-4440/ignition---tune-up-16776/spark-plugs---specialty-16898/spark-plugs---industrial-power-equipment-engines-19474/ngk-spark-plug/5469/4535864?q=5469

NGK (5469) Spark Plug, DR7EB $3.51
https://www.walmart.com/ip/NGK-5469-Spark-Plug-DR7EB/50443386

O'Reilly is just down the street, but I find it hard to believe I'd be getting the same plug from them for my K75S that I'd be getting from Amazon.

[Inge K.]

NGK (5469) Spark Plug, DR7EB $3.51
R[/color]7EB/50443386]https://www.walmart.com/ip/NGK-5469-Spark-Plug-DR7EB/50443386

O'Reilly is just down the street, but I find it hard to believe I'd be getting the same plug from them for my K75S that I'd be getting from Amazon.

The ignition system on your model is designed for non resistor spark plugs, look for D7EB instead.

[Shel]

The ignition system on your model is designed for non resistor spark plugs, look for D7EB instead.

Yes.. but that was discussed and dismissed  that forum thread I linked in my post:

http://www.motobrick.com/index.php/topic,9254.0.html

I think they're both hard to find

[Laitch]

O'Reilly is just down the street, but I find it hard to believe I'd be getting the same plug from them for my K75S that I'd be getting from Amazon.  Can anyone confirm these are all the same plug?

They're all the same plug model, but they are individual units, unless all those companies are sharing an inventory :giggles

I think they're both hard to find

If one of them is right down the street at O'Reilly's, how is it hard to find? Is it hidden inside profiteroles or teddy bears?

[The Mighty Gryphon]

It's been a while since my conversations with the service guys at NGK, but if I recall, the D7EB is not made so you can't buy them.  On the other hand, they told me that the DR7EB can be used in it's place.  I was told that the extra resistance of the DR7EB won't hurt the coils or other components in the ignition circuit, it only reduces the current in the spark, but not enough to effect firing the mixture in the cylinder. 

Since the guys at NGK sent me a dozen terminal nuts I haven't had a reason to use the DR7EB in my K75's yet as I haven't had to change plugs in any of my bikes since getting them.  I am running the DR7EB plugs in Moby Brick with no problems, but that is the specified plug for the K100RS 16V engine.  I will probably throw a set in my K75RT when I do my winter service to see how they work.

Regarding the variation in pricing, my guess is that the $14 plugs are designed for the BMW price specification.  The cheaper plugs are for domestic and rice burner applications.

[Shel]

They're all the same plug model, but they are individual units, unless all those companies are sharing an inventory :giggles If one of them is right down the street at O'Reilly's, how is it hard to find? Is it hidden inside profiteroles or teddy bears?

The NGK-5469 is easy to find, eg those 4 urls I posted.  It was the NGK D7EB and  NGK DR7EB that seem to be hard to find

What I was asking was, are the plugs ranging from$1.50 to $14 in all those retailer websites all the same?

[Shel]

Regarding the variation in pricing, my guess is that the $14 plugs are designed for the BMW price specification.  The cheaper plugs are for domestic and rice burner applications.

Have you seen the DR7EB plug available anywhere that doesn't reference the 5469

Or have you seen the strictly DR7EB selling in the $2 to $8 range. 

I may order the 5469 from O'Reilly and see if they come with the tip nuts and different plating from the picture on their website

[Laitch]

The NGK-5469 is easy to find, eg those 4 urls I posted.  It was the . . .  NGK DR7EB that seem to be hard to find
What I was asking was, are the plugs ranging from$1.50 to $14 in all those retailer websites all the same?

5469 is the DR7EB. If that is what you want, go down to O'Reilly's and get it. What's in there now? Does it have a terminal nut or a bare screw?

[The Mighty Gryphon]

According to NGK, the DR7EB and 5469 are the same plug.  The 5469 number is an NGK part number used for inventory control through the distribution chain.  The DR7EB number is a "boxcar" number that describes the plug.  In most cases, the 5469 number is used on the backside of the parts counter, while the DR7EB is used at the customer side of the parts counter.  The "boxcar" number is what you would use at the parts counter to find a cross reference to another manufacturer's plug by matching threads, reach, etc.

All you need to order plugs is the DR7EB number.

[Laitch]

Or have you seen the strictly DR7EB selling in the $2 to $8 range. 

I'm not looking. If I need plugs I go get them locally if they're to be had—usually around $3–$4. NGK, Bosch, Beru, etc.—they'll all work. I don't thrive in the miasma of comparative shopping. :giggles

The Amazon price of ~$14 is for 3 plugs, not just one.

[Martin]

A local BM tech told me I should be running resistor plugs in my K75. I ran one set of DR7EA's and I could not discern any difference either way. So I went back to D7EA's. I can't run Bosch due to my leads needing not needing the caps which are built in on the Bosch plugs. Happy with the NGK.
Regards Martin.