I know this topic has been brought up before, but I thought I'd put this out there.

I decided it was time to change plugs - since I'm at 41K (non-compensated for 33s) and still running the originals.

So I stopped at my local dealer (since I had the Encore $25 thank-you card) to pick up the plugs and I was given 6 Densos. When he handed me the plugs, Yotatech came to mind and I recalled discussion a while back about the two types of plugs - I asked and the parts guy said it wasn't the case.

I went home, found Mark Griese's write-up, (thanks Mark) and became curious.

Well, the plugs came out today, and as Mark mentioned, there were NGKs on the passenger side and Densos on the Drivers side.

Has this ever been explained?

What I noticed is that the NGKs looked great. The electrode was intact with hardly any wear. The color was great and the gaps were almost spot on for all three.

The three Densos, on the other hand, were wasted. The electrodes were worn badly and the gaps were huge and the color was poor for all three.

Well, I'm running 6 densos now and I'm not too thrilled.

Any ideas why one side differed so much from the other? Are the NGKs just superior to the Densos?

BTW: I forgot to say that I have an 02 4Runner 3.4

 

i run the ngk v power in my truck becasue its actually what my fsm says is a suitable replacement... i have no dis towards denso... it jsut seems to me that ngk is more of an aftermarket company and denso is mroe oem.... both types are listed in my fsm, denso and ngk...

 

That is really weird. Are you running the 3.0 or 3.4 v6? I have a 3.4 v6 runner, but never encounter different types of plugs in my truck. I use DENSO and NGK plugs all the time on all my cars and they have been pretty good. They are better than Bosch. You should be oki.

 

On the 3.4 as long as its a dual electrode ngk or denso you should be good. Im using 6 Denso k16tr11's which is the ones my stealer gave me so far so good. Thinking of going Denso Iridiums when the money is right.

 

you know that for the price of the iridiums, you can do about 5 changes of the regular plugs....

 

Yeah, but his Iridiums will last 5 times as long = four less times he pays/labours to change his plugs. (roll eyes)kerry people just don't see the Whole picture.

 

I went with NGK Iridiums, after trying 3 other types of plugs


* 1st set I do not even remember

* Regular Denso

* Bosh Platinum +4

I will stick with the NGK Iridium plugs from now on and their wires are great too - Nice Blue Color .

 

Denso Iridiums are about $12 each IIRC. I think the manufacturers spec them in some newer engines because plug access is so poor. Like FWD transverse engine cars with the plugs facing the firewall.

 

I have always believed that with a Japanese engine, one should run Japanese plugs. NGK's have been my mainstay for GNCC(dirtbike) races, and there the only plugs I've run in my 2.7. just my thoughts....really weird to hear about having half denso's and ngk's!

 

i've got my truck im about to change the cap+rotor and spark's,

is it better with NGK platinum or just regular?

 

[IMG]crazydog[/IMG]

 

Go with Platinum or Iridiums!!!!


My 2 cents...

 

About your observation that the driver side plugs were wasted while the passenger side plugs were fine…

It’s not the spark plugs that are the problem. Your vehicle having different plugs installed on just one side is probably that just those three have been changed once already without you necessarily knowing it (15-20K ago maybe, by dealer?).

Unfortunately this ‘wasting’ of one side before the other is actually ‘normal’. It is a side affect of firing two spark plugs at the same time in series from a single ignition coil. The same thing happens on my Tundra (3.4, 5VZFE) & my Subarus, which fire their plugs the same way.

When fired in series the spark travels across two gaps. On one plug the spark jumps from electrode to ground but on the other one it jumps from ground to electrode. The spark plug under the ignition coil (passenger side) wears normally while the plug at the end of the spark plug wire (driver side) wears prematurely. Apparently spark plugs handle only one direction of current flow well.

On my Tundra (3.4, 5VZFE) I use the OEM Densos, but the double platinum version (PK16TR11), which alleviates the issue. I also use the Denso double platinum in my Subarus. They have a platinum center electrode and platinum on the ground straps. They wear VERY slowly and easily last more than 50K miles.

I tried Bosch Platinum Iridium Fusion once in the Tundra but they were hugely worn after only 7500 miles. I’m not much of a fan of iridium as far as longevity goes. Platinum does a noticeably better job of resisting electrical erosion. The iridums do give you a finer electrode point, which is better from an ultimate performance standpoint but I have never known them to be particularly long lasting. Maybe it’s just Bosch?

As far as NGK goes, their platinum plugs are not all ‘double’ platinum. Some are and some aren’t, depends on the specific part number. Make sure you check the actual plug – the platinum disc on the ground strap will be visible. If you don’t see it, it’s not there.

Bottom line: I (highly) recommend the Denso double platinum over anything else I’ve ever used (or pulled from other’s vehicles).

 

Uhh, you responded to a nine year old post. All 3G 4Runners came from the factory with NGK on one side and Denso on the other; the heads were made in different factories with different plug suppliers. I have used the stock NGK's since 30k miles and they work fine--and I'm at 170k now. I like changing plugs every 30k; it gives a quick check of the health of your engine when you look closely at your old plugs. Plus, I live two miles from a NAPA store and they carry NGK.

 

I remember old threads like these. I remember being a 16 year old kid with wild dreams of actually being able to do amazing mods to my truck. 10 years later and I've made little progress on it and can't even drive it now that the motor died.

 

I *think* that Denso are slightly cheaper than than NGK too (profit margins might explain while dealers sell those), but both are OEM equivalents. I think NGK's are slightly higher quality however. And NGK really focuses their business on ignition components, while Denso does a bit of everything.

 

Since these old posts come up and often have useful information for those of us keeping the older ones alive, I figured it would be useful to attempt to answer the original questions asked by the thread.

This one asked why the difference in plug brands and why the driver side was wasted but not the passenger side. Neither of these questions were actually answered.

I didn't know about the different suppliers for the two heads. Interesting.

Also, I do not ever recall any thread, Toyota or Subaru, actually explaining the reason that the plugs wear at differing rates from side to side with these ignition setups (or even noticing that there is a consistent pattern to the difference).

I keep my vehicles pretty much until they are ready for the junk yard (I've never sold a vehicle) and I mechanically maintain them rather meticulously with detailed written records of symptoms, observations, speculations, and repairs made. When I review 100K-150K of records some interesting information and patterns often emerge.

Thought it helpful to pass on some experience of years so the next generation can actually understand deeper than just trouble codes and advertising claims.

 

I just thought I'd chime in since I started this post umpteen years ago.

3 Densos, 3 NGKs is how it came from the factory. I bought the truck new and that's how it looked at the first change.

My 4R has 120K+ miles and still runs great. I've been going with 6 NGKs (factory spec) every 30k or so and haven't had an issue.

 

How did you read my suggestion nine years before I posted it?

 

- Purchased new as well.
- Removed 3 Denso plugs & 3 NGK plugs at first change
- Replace my plugs every 25k with the correct NGK version
- Currently at 285,000+ miles



Andreas