the old oem spark plug "myth"

[brettsdad]

i recently changed my spark plugs on my 96 j30. the local parts store didnt have the oem plugs and i wanted to do it that day(hard to find time with a newborn). so i went with the ngk iridium plugs. iridium is supposed to be the best anyways, so, why not? i'll tell you why not. because there are several j30 owners on this forum that speak of numerous horror stories with anything but oem. i havent actually read a horror story. just rumors of horror stories. what gives guys? apparently my spark plugs are going to explode and damage my pistons and/or cylinders. well, i'm an auto service tech and i see nothing special about the j30 that would cause these cars to damage my iridium plugs 10.5 isnt that high of a compression, especially if you use recommended 91 or higher octane. i plan on browsing the 300zx forum to see how the iridium plugs work on a z32tt. probably just fine. lets stop spreading rumors guys.

[brettsdad]

just as i suspected. the guys on the z32 forum both na and tt tell the same story ONLY ITS A DIFFERENT PLUG OMG!!! come on guys its the same motor!

[yodawill2000]

NGK Iridiums will suffice ..

Throw some low end champions in there and see how she runs :O)

I believe the heat range is the issue.
Modified by yodawill2000 at 7:54 AM 2/26/2009

[brettsdad]

i wouldnt do that to any of my cars. i dont own any chevys.

[yodawill2000]

Yup That's what was in it when it left the showroom.

[colincliff2]

Yeah the horror stories sound a little far fetched to me too. I did observe a marginal difference between plug brands in my J. I had Bosch Platinums & then switched to the NGKs and it smoothed out noticeably. Somehow I doubt that Iridium plugs will cause the catastrophic damage mentioned above.

[yodawill2000]

I did see a thread in the q45 forum awhile back that showed a Bosch four prong plug that came apart.. Luckily he shut it down before it destroyed anything.

My point was the proper plug makes for a smoother idle and optimum MPG.

Modified by yodawill2000 at 1:03 PM 2/26/2009
Modified by yodawill2000 at 1:04 PM 2/26/2009

[brettsdad]

i have three daily or almost daily driven cars and i maintain all of them (100% do-it-yourselfer) one of them sees almost 8000 rpm almost daily. its remarkable to me that this myth has been going around since 92. i cant believe it.
Modified by brettsdad at 6:09 PM 2/26/2009

[yodawill2000]

I'm confused.With all due respect.And I mean that.You disagree that OEM spec plugs aren't best ??Every maker , Domestic or Import has one.Please Clarify.Once again with all due respect.

I would luv to have a shop like you do.

[brettsdad]

iridium plugs weren't around when the j first came out in 92. they weren't even around when the last one rolled off the line in 96. the iridium plug IS better and yes i believe its better for the j. its the exacts same as the oem plug with one difference, the core is iridium. copper is a better conductor than steel, gold is better than copper, platinum is better than gold, and iridium is better than platinum. better conductor=better spark. which means more complete combustion. more power, better fuel mileage, cleaner egr, cleaner motor, cleaner exhaust, your motor will last longer with less carbon deposits, your cats will last longer too. bad things happen when your gap is not right or you're out of your heat range. i've heard of iridium plugs burning holes through forged pistons before. wrong heat range. thats probably where all of the horror stories come from, or from going with lesser than oem plugs. help any?

[yodawill2000]

Yup ..Thanks.

[brettsdad]

would someone only put tires made in 92 on thier car? if your car came with mid-grade pirelli tires would that stop you from putting high end yokohama tires on. oem recommends conventional 10w-30. how many guys on this forum swear by synthetic? the stock battery in the car had 585 cold cranking amps. the red top optima i put in has 700. is that a bad thing? im not saying everything newer is better for your car. but, some things are. i'd never use synthetic oil in mine. i like my oil to stay in my motor. never use synthetic gear oil in your diff with this car either.

hope this helps

[yodawill2000]

I put Synthetic gear oil in my Diff a few years ago.Why would that be a bad thing ?

I know about the switch to snyth motor oil in an older engine. Seal leaks and such.

[J30inthe sun]

... i'd never use synthetic oil in mine. i like my oil to stay in my motor...

Could you elaborate on that? I was just thinking of switching to synthetic myself.

[brettsdad]

there are two kinds of synthetic gear lube the bad one is very rare but it will eat all seals but one specific type. we wont waste time talking about it. the other more common type, that u buy at your local parts store will still eat the seals of your differential. only differentials that come with synthetic gear oil have seals that will hold synthetic gear oil. i use 80w90 valvoline GL-5. i have learned this lesson,(regretably) on customers cars. chevy trucks to be exact. i do not kno the results of synthetic gear oil on a viscous limited slip(in our cars) since it requirs heat (viscousity) for the couplings to mate together. synthetic has a higher tolerance to heat. i use what oem recommends in this case.

[yodawill2000]

Point Taken.

[brettsdad]

the insides of a motor are smooth except for the places where there are seals. this is the place where most of your grime and dirt and the really sticky sludge builds up. synthetic oil has detergents in it that clean your motor. in theory not a bad thing. except in older motors the dirt in the seals is the only thing keeping the motor from leaking. also, synthetic being man made as opposed to dinosaur made the molecules are smaller, so synthetic is much more likely to find leaks that conventional might just flow past.

[J30inthe sun]

I was talking about synthetic in the motor as in switching to Mobil 1 engine oil. I already changed my resr diff 4 months ago with OEM recommended.

[Rex]

When it comes to the Q45/VH45DE, it's not all hypehttp://forums.nicoclub.com/zerothread?id=35940

[the converted]

copper is a better conductor than steel, gold is better than copper, platinum is better than gold, and iridium is better than platinum.

I'm nitpicking but of all those elements, copper is the best conductor. Platinum and Iridium are actually horrible conductors. They are used because they are more durable elements and can last 60k miles without being replaced. If you look at all the tuner cars, all of those guys love copper plugs because they make a better spark, and they are cheap enough to throw away after every trip to the track.

[brettsdad]

thanx for clearing that up but, which makes a better spark platinum or iridium? if copper is the best why are all of my audio/video cables gold plated? aesthetics?

[J30inthe sun]

if copper is the best why are all of my audio/video cables gold plated? aesthetics?

Gold does not tarnish like copper will, that is why it is used. I believe the tarnish will interfere with the conduction. The best conductor is silver but that tarnishes also.

[yodawill2000]

uh ..Let talk about melting points

I have a workshop foundry and gold melts at a very low point.copper is around 2300 and aluminum is aroung 1800.A gold plug would be a problem real quick

[J30inthe sun]

What would you estimate the internal tempurature of the cylinder on our J's?

[yodawill2000]

Thats way over my level of knowledge.But i would imagine its above golds melting point under heavy use ???

Gold melts at about 1832FGive or take depending on the caret above melting point is pure


Modified by yodawill2000 at 8:23 PM 2/27/2009

[brettsdad]

im confused. why did we go away from copper plugs? laziness?

[the converted]

Mostly. If you look at engines like the fwd vq's you have to take the manifold apart to change the rear plugs, so I guess it helps there.

Also with the gold video cables, it's only microns thick so it won't effect conductivity.

[RustspecS13]

FYI all nissan VLSD's are sealed. Their viscous internals have their own super special fluid. So you can put whatever you want/doesn't eat your seals. My clutch type kaaz diff is a different story.

And as for plugs, my aunt had autolites in her e30 bmw. Yea....bad idea. About 6 months later there was a hole in her piston, and the spark plug bits broke off the intake valve face and jammed two holes into the head as well. From what Ive read that was the most extreme case but its happened to others as well.

My nissans get NGK only. My first maxima had bosch's and when I switched to NGKs it smoothend out. I do know some people that have had coil pack problems with bosch plugs, they are just built differently IDK.

~Alex

[the converted]

I doubt the plugs were really the cause of that. How many miles were on the engine? Sounds like it was probably burning some oil which can cause knocking and take other things out.

[95-J30tt]

the 300zxtt uses NGK (PFR6B-11C) colder spark plugs, but they are different than the J30's plugs (BKR5EIX-11)

any spark plug for a turbo application (or any air induction for that matter) would be completely different in materials selection than the naturally aspirated plug.... dont use a turbo spark on an NA, you would be wasting your money and time (it's not worth it, and the turbo plugs are much more expensive)

i used the NGK BKR5EIX-11 for the J30's engine and they worked very well.... when i took out the VG30DE out of the J 3 years ago, it didnt have any problems what so ever.

with some experiance with materials selection, i can say that copper is probably the best conductor for a spark plug (i could be wrong), but the problem would be that you would have to change it every 3000 miles or so depending on your driving habits