Anybody Running NGK BUZHW-2 Plugs?

[Texasmark]

I had my boat out yesterday, after all the repairs and as usual it was wimpy till it warmed up. Once it did the performance, all over the rpm range was stellar.

Called NGK yesterday and talked to their tech guy. Really impressed with this man and I told him what I had for an engine and what I was running for plugs and my problem. The plugs I was running were recommended in the own man. He informed me that I had a Z missing in the part number and by adding this Z you got an inductor resistor (coil of wire, not a purely resistive element as in a conventional resistor plug) in the plug which helped, especially at cold temps to get the plugs firing correctly. Said that the RFI (Radio Frequency Interference) generated when the plug fires gets picked up by the triggering circuits and confuses them. No ifs, ands, or butts. He was very frank in his answer and had a positive no nonsense answer to every question I asked. I was impressed.

Having spent my career in the area, just a different application, I fully understand the functionality of having that coil there and it makes sense. Didn't know plug mfgrs. had done that much research on CDI engines, in particular marine 2 stroke CDI ignitions, to solve what could be (and I think is for me) a big problem. There is info on the www that tells the story and it is made for my application.

Called the local home town auto parts store and he said the warehouse had them and that they would be there this am. I'm on my way. Can't wait to run them. If this solves my initial running, cold engine, nuisance, my engine will be perfect and I will be absolutely thrilled.

Mark

 

[sutor623]

Re: Anybody Running NGK BUZHW-2 Plugs?

I love NGK plugs. Their build quality far exceeds any other manu. that I have seen. Hope to hear some good results! My '67 Merc has no thermostat from the factory, and on cold days it seems that the NGK's are the only way that I can idle and start up without any issues.

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

Did the driveway muffs test. When compared to the same plug without the Z the results were impressive. I am looking forward to the first outing with them and that is weather dependent. For $25 worth of hot dog plugs, if this solves my last issue with this engine, I will be a happy camper......heck, you can't take your sweetie out to eat (and drink tea and water) for $25.

 

[Moody Blue]

Re: Anybody Running NGK BUZHW-2 Plugs?

Interesting discovery. What motor are you using the plugs in?

 

[donaldboyer]

Re: Anybody Running NGK BUZHW-2 Plugs?

Wow, interesting stuff!

I have an '88 Merc 90hp. Will the above apply to my engine also?

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

Wow, interesting stuff!

I have an '88 Merc 90hp. Will the above apply to my engine also?

I had an 88 tower. It too had the CDI ignition. So based upon that, I'd say so.

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

In case you are interested:

From the NGK www, Design Symbols: Spark Plugs

B = 14mm thread dia, uses standard 13/16" wrench for removal

U = Surface gap (among other things)

Z = Inductive Resistor Type (coil of wire). I measured one of mine and it measured 50 ohms, cap to center electrode. The same plugs I had in the engine without the Z, the ones listed in my old repair manual, and my newer Seloc manual (BUHW-2) measured a short circuit. Regular resistive plugs, like for radio interference that have been around for 50+ years are supposed to be around 2k as I have read. The thing about the inductor vs a resistor is that the higher the frequency (fast rise time 40kv ignition pulse), the bigger the resistance (Inductive reactance), but to the current that makes the spark, the "dc" component, it is a very low resistance so you get your interference blocked but still get a good hot spark (smack). I cranked mine outside the engine with jumpers on the grounds and these plugs do produce a "snap" and very thick blue spark.

H = 12.7 mm (1/2") thread depth

W = Tungsten electrode (That's why you can run them for years and the center electrode doesn't wear off.)

-2 = I don't know what this stands for on this particular plug. Normally the - number at the end is for the gap. On current standard conventional plugs, that you would run in your truck with CDI ignition the gap is about .040" (1.0 mm....was on my Dodge 4.7 and 5.7 Dodge trucks) and a -10. I measured across the surface gap and it measured .072". Wow! That's why one gets such a huge arc across the SG. The larger the gap, the higher the voltage rises before it breaks down the gap. Since energy in the pulse follows the voltage squared, energy delivered goes up really fast, like the SG is almost double the width of the conventional gap and that's 4x the energy. That's what ensures your fuel air mix in your combustion chamber ignites and makes you GO! I'll take that.

HTH,
Mark

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

Interesting discovery. What motor are you using the plugs in?

'02 90 triple.

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

In case you are interested.

Been doing some more thinking about this RFI (Radio Frequency Interference). Recalling automobile wiring, whereas you are cautioned to not allow spark plug wires to cross one another, and the OEM's put all these plastic clips along the wires to route them nicely; they do that to keep a wire from the firing plug on one cylinder from RFI-ing a pulse into the wire of another cylinder and firing it at the wrong time, hence unstable operation of the engine. Sometimes you can see the effect at night, when things aren't properly dressed. You can see the blue glow (ozone) from the radiation. What you see is the physical effect of the voltage ionizing the air, not the associated electromagnetic wave that is transmitted from the wire and gets into your sensitive electronics.

With the high voltages and fast rise times of CDI ignitions, this became a problem that didn't exist back in the days of the coil/condenser/points. Today they run 40kv vs maybe 18kv in the old days. Course the rise time and the plug gap set the height of peak voltage of the pulse but those numbers are the unloaded max outputs. The current rise time is in the order of 4 millionths of a second(4 microseconds) whereas the old point systems rise time was in the milliseconds....a difference of 1000 times faster. The faster the voltage rises, the higher the frequency components and the easier it is to be radiated....hence shared with other wiring/circuits that aren't the least bit interested in getting it.

My 2 cycle triple fires every plug every rev. at an angle of 120 degrees. That says that when one cylinder is firing normally, another is 120 degrees into the power cycle (should be passing the exhaust ports and opening them by then) and the third is 120 degrees into the intake cycle (should be passing and closing off the intake ports by then). So, it's not hard for me to see where RFI from one of my cylinders could get into the circuits of another cylinder, especially the one on the intake stroke, and trigger it causing the plug to fire.

If the plug fires, you have not completed the compression stroke and you just have a 14.7:1 blob of combustible gas. Boom, engine misfires, big blob of white/blue smoke belches out the prop exhaust and the engine staggers. That is exactly what my engine does (did). I'm assuming 2 stroke 4 cyl. engines wouldn't react as violently as the strokes are 90 degrees apart and the fill/dump cycles haven't progressed as far as with mine and the intake probably isn't sealed off so if a bang, it wouldn't amount to much.

Just fooling around, I may wrap my high voltage leads going to the plugs with alum foil and wrap a bare wire around that, cover with elect tape to keep the elements out and tie the wires (individual wire from each plug wire) to the plate where the CDI modules are mounted (called single point grounding). That will absorb any radiated energy from the plug wires and return it to the same reference point as the sensitive low voltage circuits of the trigger circuits and if the new plugs don't completely solve the problem this should. Your 6 cylinder Continental aircraft engine has all the high voltage circuits enclosed in metal for this reason.

I don't tinker with my stuff any more, but having nothing else to do till planting season, and not being a big problem to implement, and really wanting to get this solution perfect, I think I will do that today. I just don't like my engine to cough and belch when first launched......it's embarrassing. Grin

Will post back with the results.

Mark

 

[RogersJetboat454]

Re: Anybody Running NGK BUZHW-2 Plugs?

Interesting read Mark.
If you feel as though shielding the wires makes a difference, and you want something that looks a little better than Reynolds Wrap on your wires, you may want to consider the following option;
http://www.ebay.com/itm/Accel-8011B...Parts_Accessories&vxp=mtr&hash=item3cbd3011ae

Of course this wire set is made for a V8, so you will have a bunch of extra wires, but they look good. I have used this set on a friends car that I did an engine swap to. It comes with stainless ground straps too.

 

[donaldboyer]

Re: Anybody Running NGK BUZHW-2 Plugs?

Can you take a series of pics as you do this? Would love to see how you do it!

Also pics of your lead routing

 

[bunker108]

Re: Anybody Running NGK BUZHW-2 Plugs?

I just bought a set of the "BUHW" but I am gussing that since I don't have CDI on my 72 1150(or do I) it won't make much a difference. But the firing better at cold temps thing had me intrigued. I havn't intalled these yet so should I take them back and get the "Zs"?

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

I have some pics I want to upload and show you folks some things, then I will answer any questions that occurred today while I was doing all this "Tech" stuff....yeah right. I have one more pic that I want to upload and seems the site software will only allow me to upload 5 pics. So I might just make another line item to include it.

Today was good and bad. Now you have to understand that this is a 2 stroke engine on muffs; no back pressure, no load on the engine. Things are different when you move to the two items I mentioned.

I did the foil and got it all grounded and all and it was really a waste of time. Running the engine with the new plugs thoughout all the testing today told me that the coil in the plugs (the Z thing) did as much as all the shielding I added. That was enlightening. That is cheap and no "rigging" to get-r-done.

The thing that made the biggest impression on me was the tilt angle and smoke from the engine. Keep in mind that yesterday I disabled my oil pump and I am running straignt 50:1. Testing that I am referring to in this case is at idle, engine warm. Notice the exhaust in the first two pics. I changed nothing other than tilt angle which you can see and look at the difference in the unburned fuel.

On my mod I still had a periodic sneezing, seldom but still there. Later in the testing when I took the first two pics, I had no sneezing in either instance, course as I said, the engine had warmed up.

These tests are in muffs without a load on the engine as would be had in the water.

In short, do the plugs, forget the shielding; proved nothing, add your sea foam, and when idling around the dock/no wake zone, tilt her up a tad to keep fuel from puddling at the rear of the cylinder.

Remember this can be an issue. White then black fisherman Mercs that were slanted for the lower unit to slide over logs and all and also to keep fuel from puddling at the rear of the cylinder....Merc's words, not mine.

I took all my testing material off and still have the Z plugs. First time I get out with them on "real water", I'll get back and tell you how it went.

HTH,
Mark

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

Testing. Ok, here are the other two pics I took. Apparently you can only upload 5 pics at a time. Sorry about #2. Looks like I had the shakes. Oh well.

Mark

 

[Timestep]

Re: Anybody Running NGK BUZHW-2 Plugs?

Said that the RFI (Radio Frequency Interference) generated when the plug fires gets picked up by the triggering circuits and confuses them.

I seriously doubt Mercury would let this happen. Have you tried the boat on the water, starting from cold with them fitted?

Dave (my 100th post in almost 10 years!)

 

[Faztbullet]

Re: Anybody Running NGK BUZHW-2 Plugs?

There is very little RFI on a CDM equipped engine as the module and coil are one unit, you could say each cylinder basically has its own switchbox. Once the plug fires the resistance comes into being as the coil cannot get rid of its energy in the shortest possible time due to the resistance. This reduces current flow in the spark and it takes quite a bit longer until the energy in the coil has expelled itself via resistor and the spark gap (air gap is also a resister) This results in a longer spark but however the spark is somewhat weaker due to energy loss from the resistor. The reason why the resistor helps to suppress RF is the resistor sort of stabilizes the rate of current flow , resulting in "flatter" edges on the voltage vs. time curve . This implies less high frequency components of the signal in the cable feeding the spark plugs. So simply the RI plugs just make the resistance high so coil saturation is longer thus resulting in a higher voltage to fire the plug, the result is the longer spark time which may result in better combustion. Also certain testing without backpressure on engine is not to reliable.

 

[Texasmark]

Re: Anybody Running NGK BUZHW-2 Plugs?

There is very little RFI on a CDM equipped engine as the module and coil are one unit, you could say each cylinder basically has its own switchbox. Once the plug fires the resistance comes into being as the coil cannot get rid of its energy in the shortest possible time due to the resistance. This reduces current flow in the spark and it takes quite a bit longer until the energy in the coil has expelled itself via resistor and the spark gap (air gap is also a resister) This results in a longer spark but however the spark is somewhat weaker due to energy loss from the resistor. The reason why the resistor helps to suppress RF is the resistor sort of stabilizes the rate of current flow , resulting in "flatter" edges on the voltage vs. time curve . This implies less high frequency components of the signal in the cable feeding the spark plugs. So simply the RI plugs just make the resistance high so coil saturation is longer thus resulting in a higher voltage to fire the plug, the result is the longer spark time which may result in better combustion. Also certain testing without backpressure on engine is not to reliable.

Agree on the RFI comment. I was just curious about the leads radiating. Course they are away from everything which helps. Wasn't doing anything yesterday and thought I'd just see if it made any difference....it didn't.

As I mentioned, the coil's dc resistance was only 50 ohms. Don't know what the inductive reactance is at the rise time (frequency) of a 4 usec pulse.

Yea verily on the muffs testing being unreliable.

I'm about through fooling with it. It's in pretty good shape right now and I think it will work ok.

Mark

 

[MassillonBuckeye]

Re: Anybody Running NGK BUZHW-2 Plugs?

Any updates?

 

[Dick Bacon]

Re: Anybody Running NGK BUZHW-2 Plugs?

Just removed and cleaned the carbs on my 88 70hp 3 cyl for a poor start problem and wimpy until warm problem. Would these plugs work for me for this problem. Would there be any harm to the motor in trying them ?

 

[dandreye]

Re: Anybody Running NGK BUZHW-2 Plugs?

Hi Mark,

Wondering how BUZHW-2 spark plug testing went under load back then? I've got exact same engine and thanks to your thread have just learned the difference between BUZHW-2 and BUHW-2 as far as engine performance impact is concerned. By luck I've always had BUZHW-2 ones installed and keep on board a set of 3 spare BUHW-2 ones, which are apparently a lot cheaper. My outboard still doesn't always start perfectly when cold although there are clearly other reasons for it to behave so (in particular compression in one cylinder being significantly lower than in the other two and also no proper water separating fuel filter installed). But once warm it starts and runs great and just has rough idle, which as we know is the nature of the beast.

Thanks in advance,

Dmitriy