standard vs platinum electrode sparkplugs. Opinions?

[Nos4r2]

In my years running bikes on a few occasions I've used Bosch platinum tipped plugs. These are horribly expensive but make a he11 of a difference to certain brands but none to others.<br /> When they work they improve MPG, reduce misfire rate (with a standard plug you have something like a 10% misfire rate as standard when the engine's running right-it's just that you don't actually notice it<br />They improve throttle response an enormous amount. For example on my tatty old Suzuki GS850 they make the engine change from sounding like a tourer to a sportsbike. They do however mean that the engine has to be spinning a bit faster to start, even when push starting. Thats using a direct equivalent plug but platinum.<br /><br />At 4x the price of normal plugs though it's an expensive experiment, so I'm wondering if anyone's tried them in any outboards and found a difference?<br /><br />To clarify, I'm talking about the platinum tipped plugs with +ve electrode like a thick needle and a -ve electrode that comes to a sharp point too.

 

[cobra 3.0]

Re: standard vs platinum electrode sparkplugs. Opinions?

I couldn't tell the difference on my 3.0 with NGK platinums, so I went back to the GM plugs specified in the manual.

 

[Nos4r2]

Re: standard vs platinum electrode sparkplugs. Opinions?

I found the same with the NGK's-they don't make a lot of difference in my bike. The bosch do though.

 

[BillP]

Re: standard vs platinum electrode sparkplugs. Opinions?

Never tried them in a boat but I ran Champion and Bosch platinum types in three bikes and yes there was a notable difference in performance and especially longer life...900 Kaw, 750 & 1100 Suz. The only engine I've had good performance with NGKs is a 2 stroke 38hp Kaw engine in an ultralight plane.

 

[TwoBallScrewBall]

Re: standard vs platinum electrode sparkplugs. Opinions?

I agree, and it is in fact hit or miss. <br /><br />Tried them in a few cars, the most noticable was when I put them in a 1994 Escort GT with a DOCH 2.0L inline 4cyl. Huge difference in idle, throttle snap, and they did improve MPG though nothing drastic, maybe 2-3MPG on a car that got 34 all the time. <br /><br />Never tried in a boat, but would be an interesting experiment, though expensive. <br /><br />Would be nice to hear from some folks who did.

 

[Nos4r2]

Re: standard vs platinum electrode sparkplugs. Opinions?

yeah my thoughts exactly. I'm tempted to try it next change as the decreased gas consumption would pay for them quite quick IF it works. It'd be nice to know in advance though.

 

[Perfidiajoe]

Re: standard vs platinum electrode sparkplugs. Opinions?

I've used NGK's in my 225 EFi Merc, & saw little or no difference from the Champions, Even though the dealer said the NGK's were better. Seems to be a case by case thing.

 

[WillyBWright]

Re: standard vs platinum electrode sparkplugs. Opinions?

I personally have never noticed any differences between sparkplugs in performance except when changing between surface-gap and conventional sparkplugs on conventional motors. In the new DFI's the right plug is very important. Otherwise, Platinums tolerate fouling better, but that' about the only advantage. And with today's oils, fouling isn't much of a problem anymore. In the 60s and 70s, Dang Straight!

 

[dajohnson53]

Re: standard vs platinum electrode sparkplugs. Opinions?

Originally posted by WillyBWright:<br /> I personally have never noticed any differences between sparkplugs in performance except when changing between surface-gap and conventional sparkplugs on conventional motors. In the new DFI's the right plug is very important. Otherwise, Platinums tolerate fouling better, but that' about the only advantage. And with today's oils, fouling isn't much of a problem anymore. In the 60s and 70s, Dang Straight!

Is there an inherant performance difference between surface gap and conventional? <br /><br />My '82 V6 main engine original specs called for surface gap, but now the spec is for a conventional plug. I don't know if it's because things changed in the past 20 years or because when it was remanufactured in the mid-90s, different ignition parts were put in (I know it's got different ignition parts, but don't know if that's the reason for the change in plug).<br /><br />My little kicker, 30 years old, is all original (except for the coil I replaced yesterday - what a difference two cylinders makes!). It called for surface gap and that's what I'm running. <br /><br />Just wondering why some call for surface gap, some don't - and how a guy would decide which conventional to swap in for an experiment, if that would make a difference, etc.

 

[WillyBWright]

Re: standard vs platinum electrode sparkplugs. Opinions?

Good questions.<br /><br />It's easiest using Champion numbers when determining what can be substituted. L76V and L78V are very popular surface gap plugs in both Mercs and Johnnyrudes. A close conventional equivalent to both is L77JC4 which is also very common on Johnnyrudes. L is the thread size and depth, the number indicates the heat range, and the suffixes denote the electrode(s). The first letter has to be the same, the number has to be close. The rest depend on what kind you want.<br /><br />Conventional sparkplugs work best in low RPM 2-strokes and all 4-strokes. Surface gaps work best in high revving 2-strokes.<br /><br />I generally prefer conventional plugs in pull-start motors, but that's just me.

 

[Nos4r2]

Re: standard vs platinum electrode sparkplugs. Opinions?

What sort of performance/fuel economy improvements do you see with surface gaps? I've only ever seen them once in a '67 red band I bought but never ran. Our local OB repair shop doesn't stock them but will order them-he's on a river with an 8 knot speed limit so I guess there's very little call for them.

 

[dajohnson53]

Re: standard vs platinum electrode sparkplugs. Opinions?

Thanks WillieBWright. That makes sense. I'll ask you a related question. My little kicker calls for surface gap L77V. When I bought it (very used) last fall it had some conventional plugs in it (can't remember which one). I replaced with a surface gap plug the local Merc dealer said were the right plugs - a NGK BUHW-2. No huge difference with the plugs that were in it - both worked OK (considering the engine had a bad coil and dirty carb - both now fixed). I find out now that the BUHW-2 is more like a L78V, not 77 (the NGK "equivalent" to the L77V would have been BUHW). Today I tried to find some actual Champion L77V and the autoparts store said "our computer shows they've been superceded by L76V." And that's what they have.<br /><br />I'm thinking that there's not a HUGE difference between L76V, L77V, L78V, and I should probably just run the two options that are available locally - the NGK BUHW-2 and the L76V - and see which one works best for my trolling set up. Is what they told me true (76 replaces 77), and/or is it worth while making more of an effort to come up with the actual exact spec'd plug?<br /><br />Would I even be asking these questions if I was doing what I should be - out on the water (probably satisfied, not questioning the plugs I have).<br /><br />Thanks.

 

[WillyBWright]

Re: standard vs platinum electrode sparkplugs. Opinions?

BUHW-2 is equivalent to L78V and BUHW is equivalent to L76V. 77 is close to both and the supercession was probably a flip of a coin. They're awfully close. You can stay within 5 numbers (two up or down, and the right one) and still be close enough to run without any worries.<br /><br />As far as performance improvement with surface gaps, idle will be higher but top end won't be terribly noticable. Surface gaps typically last much longer if they don't carbon-up. That's where the higher RPMs come in. Mileage is going to be too close to call.

 

[dajohnson53]

Re: standard vs platinum electrode sparkplugs. Opinions?

Originally posted by WillyBWright:<br /> BUHW-2 is equivalent to L78V and BUHW is equivalent to L76V. 77 is close to both and the supercession was probably a flip of a coin. They're awfully close. You can stay within 5 numbers (two up or down, and the right one) and still be close enough to run without any worries....

Again thanks for the spark plug info - it's a learning experience for me and I appreciate the information. So...<br /><br />To reiterate, my 9.8 Merc calls for Champion L77V. Currently readily available (apparently - haven't searched far and wide) are L76V and L78V. If I were to tell you that this is a trolling motor pushing a boat that weighs loaded about 2500lbs, which direction would you go, since the exact recommended plug is not available? Would this advice change if I was using the motor to push a small skiff at planing speed and WOT type situations? I'm guessing it doesn't make a huge difference either way, but am curious which direction you'd go if deviating from the exact spec'd plug.