Changed all plugs today.

[toddt]

About 19.5K miles.

Old plugs looked good, gap varied by about .005.

No noticable change in performance.

Gapped them to .038

Easiest car to work on I've ever seen.

Past major jobs:
Rebuilt AXOD auto trans, 88 Ford Taurus
Same car, full top/bottom end rebuild.
Tie rod end swap, many, many times.

85 Kawasaki 900 Eliminator, Replace broken timing chain. Full engine rebuild. Valve adjust many many times.

88 Ford Mustang, full coolant system redo, pump radiator, etc.

93 Ford Aerostar, 4.0 all plug swap.

96 Chevorlet Camaro Z28, LT1, Blower install/uninstall. Transmission Rebuild and upgrade. Valve body upgrade.
Injector upgrade. Suspension upgrades (didn't do springs)

Among all those vehicles, VIPER IS NUMBER 1. By a LONG SHOT with the exception of the moto. (duh)

I've NEVER changed FOUR plugs in the time it took me to change these 10.

Viva Viper. I'm 100% sold on this car.

 

[99 R/T 10]

What kind of plugs? Most use champions, I put some in about 3000 miles ago and they are working great. I do want to try the Splitfires though because of the better burn capability.

Mike

 

[toddt]

I used Autolite cheapos.

I can guarantee the performance is the same as splitfires.

(search the group for splitfire to find out more)

 

[99 R/T 10]

Autolite cheapos?! I heard the splitfires add 20 HP to the rear wheels! J/K, I did the search, found one short thread. I might try them when I go to the dyno in a month or so. I'm thinking of doing two pulls and then switching the splitfires in just to see what happens.

Mike

 

[genXgts]

Keep us posted on the results if you dyno pre/post spiltfires please!
In the Mustang world they did dyno around 5 or 6 at the tires in repeated tests with Spiltfires, but this board didn't seem too keen on them, so I didn't go with them on the GTS, did the RC12LYC at 2 bucks a pop.

 

[toddt]

If anyone can demonstrate a performance increase with JUST going to splitfires without indexing or changing anything else, gap .038, I will lovingly perform you next plug change FOR you, and buy all the plugs. Hell, I'll even change your oil and buy THAT for you.

 

[99 R/T 10]

Well,
I don't know if I will get any performance gain, but it will be interesting to see what the results will be. toddt, if your offering to do all that if it does show a gain, what happens if they drop HP?

Mike

 

[Ron Hickey]

Some Viper owners have used platinum plugs and even the Bosch Plus 4's and are satisfied with them. However, the consensus on this board has always been to stick with the stock Champions. A search for "Spark Plug" should yield some interesting reading. As far as the Split Fires go, in 4 years on this board I've never seen anyone recommend them -- all posts have been negative, like this one . I've used the stock Champions on my Vipers.

Replacing the wires is a must. The stock ones are OK, but they won't last as long as the Mopar Performance ones or aftermarket products like MSD or Magnacore.

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by wilddude:
what happens if they drop HP?
<HR></BLOCKQUOTE>
I guess you'll have to learn to shift faster to make up the difference.

 

[joe117]

I always thought that the spark plugs job was to start the fire. If it starts the fire then it's job is done. If the fire doesn't start then you have a miss and you can feel it. If there is no miss there isn't much more that a plug can do for you. The plug can't start half a fire. I guess you could have a hot plug that might cause pre-ignition, but of course you would notice the knock caused by that. Vipers do not have high compression engines compared to a race car or a hot car from the 6os. I don't think Vipers are ******* their plugs and I don't think there is anything to be gained by changing them before they need it. What does it say in the book?
As far as the split fire plugs, I'm not sure that you would get more than one spark from them anyway. One side of the ground member is always going to be an easier path and in an engine under load all the spark will jump to that side.
I think people keep messing with their plugs because it's something they can get to without much trouble. If there was any performance gain to be had with a trick plug, why would a big company like DC not put it in the car to star with?

 

[99 R/T 10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Ron Hickey
all posts have been negative, like this one . I've used the stock Champions on my Vipers.
<HR></BLOCKQUOTE>
I did read that one post(was the only one I found on the splitfires), I happen to get some of these plugs cheap and figured I would give them a try. I was going to go to the dyno anyway.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by toddt
I guess you'll have to learn to shift faster to make up the difference.
<HR></BLOCKQUOTE>
Ha, I shift so fast now I miss shift. Hey toddt, I am heading to Cali tosee family and will be hooking up with Tomer on the 13th, maybe see you there?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117
As far as the split fire plugs, I'm not sure that you would get more than one spark from them anyway. One side of the ground member is always going to be an easier path and in an engine under load all the spark will jump to that side.
<HR></BLOCKQUOTE>
I think its the quality of the spark that it is suppose to improve, don't really know for sure myself, but it will be interesting to see the results.

Mike

 

[Ron]

<FONT face="Comic Sans MS">Not sure what wears a plug, the spark itself or the combustion process, but remember our engines fire the plug twice per complete cycle. One for it's own power stroke and one waste spark while it's sister cylinder combusts.

If it's the spark itself that causes the electrode erosion, I'd guess that our plugs would last 1/2 as long as other engines. Regardless, the manual states the recomended mileage interval.</FONT f>

 

[Mike Brunton]

The wear a plug sees is mostly caused by a tiny amount of the electrode vaporizing when the spark occurs.

Copper is actually a BETTER conductor than platinum is, the thing is that platinum plugs just lose much less of themselves due to vaporization. This is why platinum plugs can go for 100k miles and copper plugs are not rated for this long.

The only benefit to a splitfire plug would be that it would expose a bit more of the spark surface to the combustion mixture, although I think the benefit would be negligible.

A copper plug, gapped correctly, with a good wire giving it adequate power will produce as good a spark as anything.

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by wilddude:

Ha, I shift so fast now I miss shift. Hey toddt, I am heading to Cali tosee family and will be hooking up with Tomer on the 13th, maybe see you there?

Mike

<HR></BLOCKQUOTE>

Yeah baby! Actually, I talked to tomer on the phone the other day and told him I'd set up a friday night with the danville/san ramon guys.

And I will, too...soon.

So let's all hook up when you get out here.

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117:
I always thought that the spark plugs job was to start the fire. If it starts the fire then it's job is done. <HR></BLOCKQUOTE>

Joe--

I don't claim to be a combustion scientist, but I've studied the issue a little.

The short version is this: When the spark occurs, a flame front starts. That flame front moves progressively through the charge.

The quicker the flame front consumes the charge, the more power you will make.

The MOPAR HEMI became scary famous becuase Dodge was able to patent a method for putting the plug tip RIGHT IN THE CENTER of the chamber. In this case, the flame front would reach all points faster than ANY OTHER POSSIBLE plug location.

This is why that for a given engine size, the HEMI outperformed all other designs. It's also why you will find the exact same hemi design in every top-fuel dragster.

So essentially, all I'm saying is that you are right!* Only the position of the plug really matters. And we don't have a choice there, except to index. Even here, I'm convinced that the position of a plug will only hurt you if the ground wire is between the electrode and the center of the piston. Every other position of the plug doesn't hurt or help you.


*EXCEPTION: The enormous charge densities present in supercharging and turbocharging can actually PREVENT a spark from successfully burnning through the charge. ("your spark's blowin out, dude!"). This is why you ALWAYS need a high voltage MSD type system in those cases.

 

[joe117]

The modern high power ignition systems have so much more power than the old points and coil systems that the plugs will now fire properly without so much dependance on the state of wear of the plug itself. I think plug wear is caused by the hot combustion gasses and not the spark. Again, IMO, the plugs in a stock Viper engine will do their job to perfection for many tens of thousands of miles and changing them before they are truly worn is just adding to wear and tear on the threads in the head. The improvement that might be gained by changing plugs after 10k miles, in a stock engine that shows no problems is probably mythical. The possible damage to the threads and plug wires is very real.
The idea that a plug with more than one electrode or some kind if a split fire arrangement giving a bigger spark and starting a bigger fire in a stock Viper engine, is probably a good marketing idea and nothing more.

 

[Butch The Snake]

I like the Champion plugs, I am switching over to them.

 

[Mike Brunton]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by joe117:
I think plug wear is caused by the hot combustion gasses and not the spark.
<HR></BLOCKQUOTE>

This is simply not true. The only difference between a platinum plug and a copper plug is the platinum plug has a tiny disc coated in platinum on the end of the electrodes. The rest of the plug is the same a as a standard plug. Copper will vaporize moreso than platinum will - which is why copper plugs must be replaced more frequently. Check NGK's website for a lot of info on this - plugs wear due to sparking, not because of the hot combustion gases.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Again, IMO, the plugs in a stock Viper engine will do their job to perfection for many tens of thousands of miles and changing them before they are truly worn is just adding to wear and tear on the threads in the head. The improvement that might be gained by changing plugs after 10k miles, in a stock engine that shows no problems is probably mythical.
<HR></BLOCKQUOTE>

Vipers tend to run lean in some cylinders. When I removed my plugs after about 15k miles, the right side plugs looked like they had 100k on them - the electrodes were charred, worn and noticeably reduced in size, whereas the left side plugs looked fine. I drove the car hard though. After replacing (with stock plugs), the idle was a bit better, and the car made a few more HP on the dyno.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
The possible damage to the threads and plug wires is very real.
<HR></BLOCKQUOTE>

I don't think there is a real danger of damaging your engine unless you do something really silly... just make sure you use anti-sieze, dielectril jelly in the plug boots, and be sure the plugs are not cross-threading (should go in more than 1/2 way just w/fingers).

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
The idea that a plug with more than one electrode or some kind if a split fire arrangement giving a bigger spark and starting a bigger fire in a stock Viper engine, is probably a good marketing idea and nothing more.
<HR></BLOCKQUOTE>

If they say it gives a bigger spark, it's an outright lie. The real benefit is there are multiple paths for the spark to jump between the center and ground electrodes. There will always only be one spark, no matter how many electrodes there are. however multiple electrodes would allow for a more exposed spark, and would overcome problems that might arise from gunk getting on part of one electrode.

Platinum plugs are great - but not for horsepower, just for longevity. Platinum plugs tend to run hotter at the electrodes, and can cause detonation and pre-ignition more so than regular plugs. This, and the fact that high cylinder pressures/temperatures can cause the platinum disc to become dislodged are the reasons these plugs are not recommended for nitrous/turbo/supercharged applications.

The only time to use platinum plugs is if you want to get 50k miles or more between changes. Spark plugs for the Viper are cheap, and very easy to change. There is no reason not to change them out every 20k miles or so.


P.S. ToddT, a trick many racers use is to 'index' the plugs so that the open side of the plug is facing towards the center of the chamber. It can be good for a few horsepower - if you have the time and inclination to do it.

 

[99 R/T 10]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Mike Brunton
P.S. ToddT, a trick many racers use is to 'index' the plugs so that the open side of the plug is facing towards the center of the chamber. It can be good for a few horsepower - if you have the time and inclination to do it.
<HR></BLOCKQUOTE>
So, isn't this the advantage of the Splitfires? They open up the spark to the chamber without having to index, right?

Mike

 

[joe117]

Mike B., Perhaps you are correct concerning the platinum tip plugs and electrode wear. I don't know the facts about platinum plugs. When I say that the spark isn't the wear factor, I'm thinking back to all the old worn out plugs I've seen. Not the kind that would come out of a Viper. I mean real worn out plugs that show obvious wear. It seems to me that they typically show wear on not only the point of spark but all metal parts, the entire electrode and the insulator too. That's why I'd say that hot gasses are doing the most wear and tear.
toddt, The way I remember the value of a hemi chamber was, like you say, that it provided the shortest distance from the plug to the edges. I'm not sure I buy the idea that you make the most power with a hemi because you burn the charge quicker. I thought that this short distance was an advantage because the flame front accelerates as it travels and if you let it travel too far it will become supersonic and at that point becomes a detonation. This limits the compression ratio you can use and you could use more with a hemi. The hemi also, I think, will let you have the largest pair of valves possible for a given chamber volume. Perhaps I remember this wrong. Could be.

 

[EXECMALIBU]

my experiance with spark plugs seems to conflict with the post about copper conducting as well as platinum! not in vintage 2 stroke racing motorcycles

when i installed a new ngk bp8e-s (copper plug) in vintage racing bultaco motorcycles the bikes are difficult or near impossible to start!
sometimes you can kick your *** off trying to start them when they are cold!

i once tried a used ngk bp8e-v(platinum) @ $5 per plug and the bike started amazingly on the first kick!!

i thought that maybe something was defective with the new bp8e-s (copper)plug so i tried another new one..kicked my as off! would not start!

i put the used bp8e-v (platinum) back in and it started on the first kick again!

just to make sure i was not going crazy, i tried the e-v plugs in 4 other bikes (2 and 4 strokes)
and they all are much easier to start with the e-v!


the same manufacturer (ngk) same reach and heat range bp8 but a different material! with radically different results!

needless to say i always use the platinums plugs in everything i own.

just my .02

 

[joe117]

I looked up the conductivity of platinum and found it to be only 15% that of copper. That being said, I still wouldn't say that there would be much difference between the overall conductivity of a "platinum" center electrode. In his post, above, Mike B said that the platinum plug has only a tiny disk of platinum on the electrode tip. This small amount of poor conductor in series with the copper would not change the resistance much. It would make sense that there couldn't be much platinum in the plug or they would be much more expensive than they are.
I would guess your experience with the hard starting dirt bike being plug sensitive was something other than the platinum. I myself remember bikes that were plug sensitive in one way or another. I'm thinking it has to do with a magneto that gives marginal spark at low rpm.

 

[Scott J]

toddt:

Let me know when the Danville/San Ramon guys get together, I haven't taken the car out in a while [newborn at home] and it needs the fresh air.

I'm at the end of Crow Canyon.

 

[JonB]

Remember, Im the guy who believes that electrical wire is manufactured from tightly-compacted smoke particles, pressed into a plastic sheath. I proved this theory simply by crossing most any 2 wires, and immediately see the smoke leaking out.

That said, CHANGE YOUR PLUGS EVERY 10K-15K miles! It cures a bevy of idle/miss/backfire-pop/misc ills. Some you did not even know you had till you changed plugs.

Not only is the visible wear of electrodes a factor, but internal plug breakdown appears to play a major role in our very high energy ignitions. MANY fellow Viper owners have stated how surprised they were by the smoother accelleration simply from installing new Champion plugs, and/or new wires.

OE spec "Long Reach" Plugs are essential. The plug must reach more deeply into the cyl for the best performance. Someone even suggested that a shorter plug was, in effect, adversely affecting the timing. While I dont necessarily believe this, he felt the better peformance was a result of the deeper-timed spark.

If you like ShytFires you probably like those 3-bladed Turbo razors? "The first blade stretches the whisker and before it can snap back.....etc, etc, etc." And don't forget to Lather, Rinse, Repeat. Hee Hee !!

 

[HP]

Platinum is used because it is one of the most stable metals.
Remember the Periodic Table from chemistry? It is less prone
to oxidize. Is a platinum plug better? Not necessarily, there
is more to a plug than the metal in the electrode. I just changed plugs on my Harley, because the Autolite platinum plugs
were separating at the ceramic-metal connection. One plug had
already separated to the point where I was getting blow-back
out the top of the plug.

 

[toddt]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Mike Brunton:
P.S. ToddT, a trick many racers use is to 'index' the plugs so that the open side of the plug is facing towards the center of the chamber. It can be good for a few horsepower - if you have the time and inclination to do it.

<HR></BLOCKQUOTE>

All I'm saying is that I don't think you don't have anything to gain by indexing. You only have to lose by not indexing. It is only when the electrode sits between the spark and the center of the chamber that you lose. (it may block the flame front from spreading as quickly to the center.

This is a very small angle we are talking about. If the center contact of the plug has line-of-sight to the middle of the chamber, you do NOT need to index, period. You will gain nothing.

I suspect that this is the reason why most people gain just that from indexing.

You'll only see a gain if, before the indexing, one of the electrodes was blocking line-of-sight to the center.

 

[Mike Brunton]

Todd,

I think we're agreeing with one another

You mentioned the idea, I was just saying you were right, it's something racers have been doing for a while to get the most advantage they can.

 

[Ron]

<FONT face="Comic Sans MS">Not having a cylinder head handy, is the center of the combustion chamber directly below (6 on a clock dial looking at the plug hole) the plug? </FONT f>

 

[schorvitz]

Sean Roe recommended I use Autolite 3923 plugs in my GTS today. I did a search for these plugs on the ViperClub board and found nothing. Could someone let me know about these plugs and if they are a good choice. From what I understand, these plugs are "colder" -- not quite sure what that's going to buy me

Eric

 

[v8huntr]

I used to have plus 4 in my car and all I can say is that they are great plugs. I don't recommend them to cars with NOS or force induction because it might cause detonation. throttle response is much better with Bosch plus4 then any other plugs I have tried in my viper.