spark plugs

[madtodaimax]

i am thinking about replace my spark plugs on my 22re. i was wondering if there is a real advantage to spending for iridium plugs over the "standard ones"

[humanoid]

In a NA vehicle, I think the advantages are negligible (i.e. not noticeable).

[Mushroom_Toy]

Just get a nice Japanese made plug, like NGK or Denso. Japanese things play well with other Japanese things. Just get the one to two dollar NGK's they work great, don't waste your money on the iridiums.

[rpmspeedyBlue]

usually if your standard plugs are not lasting or being fouled up I would up grade.

[JackMHigh]

I work at an autoparts store (i know...nothing special) from my own personal experience and customers...Unless you have a turbo or a hi performance big block you won't notice a difference. The only difference between copper and platinum is platinum last longer and "supposedly" gives you better mpg. Iridium isn't going to do anything special....especially in a toyota. Stick with NGK v-power's....or bosch+2 if you want platinum.

[ffpmlex]

I have a 96 Tacoma, 4-cyl w/ 3RZFE...got the iridiums and didn't really notice a difference...only cost me about $15 extra though!

[RAV4Don]

Iridiums last a long time, much long than plats from my experience. I changed wifeys RX300 iridiums at 117k miles believing that they should be worn out long ago. Not! They looked good so I decided to check their gap. Darn, they gapped the same as the oem recommeded gap. If I hadn't don't the work myself I wouldn't have believed it. If you want to install a set of plugs and forget them Denso or NGK iridiums are the ticket!

I still run NGK coppers in my performance vehicles because I change them frequently, but for my stock daily drivers I will be using iridiums.

[Bernd]

Vehicle: 1994 Toyota Caldina Wagon, 2 liter 3S-FE engine 140 HP

Application: family car, town&country driving in Japan (not racing, the main goal was fuel economy and a bit more accelerating fun)

Not tried: platinum or iridium .

Stock Denso plugs: thrown out after 13,000 km becasue of rough idling. Gap edges were worn round.

Splitfire, gapped to 1.1mm (0.044 in): proper idle restored, a tad more pulling power. After 21,000 km still going strong, replaced with...

Bosch 4-electrode: power comparable to Splitfire, just more expensive. Eager to try something new, affter just 6,000 km I read about ...

DirectHits capacitors on non-resistance plain $2 Bosch plugs: did not trust mfg claims, frst tried out principle on my bench with an old spark coil and cable, a leftover high-voltage 470 pF cap and makeshift gap and contact. Without cap, a normal spark as we know it outside the engine. With cap: bang. So they got my bucks.

Price/Delivery: ~150$ for the kit with wires, got non-R plugs locally (Bosch). First kit had wrong boot covers, (round, needed the square ones), got replacement delivery prompty and courteously to my overseas address. Nice. Installed on 2001-11-01 with 1.1 mm gap (0.044 in).

Performance: noticeable better engine response. Fuel economy not clearly evident on the log, because of variation in driving pattern and driver. My wife seems to use 10% more fuel than me, the savings from Directhits effects on my car does not show up clearly. If you are looking for raw power gain, there may be other mods with more bang for the buck but then this was not an expensive upgrade and provides the reliability needed for a family vehicle .

Value: Did I get my money's worth? Likely yes, however, we do not drive that much and can only estimate the gain. If the fuel savings are in the 5% range, this amounts to 200$ (regular in Japan has been about 5$ per gallon, now inching to 6), if it is 2% we only had the savings from not having to replace the plugs (they look good for another 25000 km) and our small fun in acceleration and reduced emission (idling CO measured below 20 ppm).

Validation: preparing to sell the car I removed the DirectHits kit and spark plugs. At 25000 km the cheap Bosch plugs look less worn and run better than the stock Denso plugs after 10000 km (replaced stock with Splitfires because of idling problems). SF had improved response a little. Back to the SF and stock cables now, some of the pull is missing and exhaust noise is noticeably more when climbing or accelerating. Less of the fuel burns in the cylinder, more in the exhaust. Idling CO still at 20 ppm, so the plugs do little at idle. . I cannot use my small pocket meter while driving.

I also installed the smaller DirectHits caps in my motorcycle (400cc 4-cyl Kawasaki) . Noticeable power gain but misfiring on hard accleleration. Had to reduce the gap a little. A hot starting problem remained, the engine had 2 coils each firing 2 gaps, the voltage when the coils got hot was not enough in this configuration.

Our next car will have a 1AZ-FSE 2L direct injection engine with one ignition coil per cylinder. Unfortunately, it seems there is no DirectHits kit for it.

[smasheromalley]

I always get a chuckle when I hear of someone replacing worn out plug with splitfires and then claiming they were worth the extra money. Replacing a bad plug with a good plug, splitfire or not, is going to make it run better.

And a warning about claimed 100k mile plugs. The problem usually isnt with the electrodes wearing out in that time, the problem is with threading steel into an aluminum head and leaving it there for 100k miles. If youve ever pulled the threads out with the plug or, worse yet, broke a plug off in a cylinder head you'll know what Im talking about.

[RAV4Don]

Originally Posted by smasheromalley

And a warning about claimed 100k mile plugs. The problem usually isnt with the electrodes wearing out in that time, the problem is with threading steel into an aluminum head and leaving it there for 100k miles. If youve ever pulled the threads out with the plug or, worse yet, broke a plug off in a cylinder head you'll know what Im talking about.

I use high quality antiseize on plug threads in alum heads and never had any problems such as you mentioned. But you point is well taken that there is risk from leaving any plug in any head for a very long time.

[Bakemono]

The Iridium plugs will not wear as quickly. However, on a stock engine I dont think they will make a huge difference. They also cost about 3 times as much as standard plugs, so you have to factor in the added cost as well.
I would not buy Bosch sparkplugs (junk), go with NGKs or Densos. Dont get cheap plugs though, they wont last. Go with double platinum.
My advice to you would be to go with OEM plugs. They were designed for your engine and they will work the best in that engine.
Cap'n

[Bernd]

Originally Posted by smasheromalley

I always get a chuckle when I hear of someone replacing worn out plug with splitfires and then claiming they were worth the extra money. Replacing a bad plug with a good plug, splitfire or not, is going to make it run better.

And a warning about claimed 100k mile plugs. The problem usually isnt with the electrodes wearing out in that time, the problem is with threading steel into an aluminum head and leaving it there for 100k miles. If youve ever pulled the threads out with the plug or, worse yet, broke a plug off in a cylinder head you'll know what Im talking about.

Right you are, switching from old plugs to -any- new one, I might have fooled myself on the power impression. The trend on my fuel consumption log is not clearly up, either, only clearly not downward. However, as the non-OEMs last twice as long or more, I still get my money's worth.

I get a chuckle out of the statement of the plugs being "designed" for the engine: size and heat rating have been "designed" and tested - fine, but the maker puts in the cheapest plugs he can get that fit the specs and will not fail unduly within his warranty. He does not pay for the gas, he has no savings from putting in better plugs. We the owners/drivers do, and we share our personal observations. You choose whom you trust and whay you try out.

Thanks for the tip with the antiseize. Getting the plugs out after 30,000 km is more stress than after 13000 indeed. Don't use silicone, it can foul up oxygen sensors.

[nofear4189]

yea, i had to use a darn impact wrench to get my old plugs out at about 130 ft/lbs Every cylinder. I dont know if they were cross threaded, or jsut in there forever. I didnt use anti-seize on the new ones, but i should have. Oh boy, i cant wait until i have to take them out again. The new ones went in easier than the olds came out, but not as easy as they should. Im thinking the threads are screwed up in the block.

-Adam

[RAV4Don]

Originally Posted by nofear4189

I didnt use anti-seize on the new ones, but i should have. Oh boy, i cant wait until i have to take them out again.

-Adam

Always, and I mean always, use a premium antiseize when two dissimilar metals are in contact for long periods under pressure. By quality I mean a "nickel" type antiseize (that includes nickel, alum, and graphite in a heat resistant high pressure lubricant.). Most heads are made from alum now and all spark plugs that I see are steel. These two metals don't behave well together for long periods under pressure and the result is corrosion, gauled threads or seriously stripped threads due to seizing. One brand that works better than the ordinary stuff at the chain parts stores, is SAF-T-EZE. Goofy name but they sell the premium nickel version. There is also a much more expensive type called "Nuclear"or something, that is formulated to much higher standards not needed on street vehicles. I have only heard of it but never seen it.
Also, there is no need to apply high TQ on the spark plugs. On all the heads that I have worked on the recommended spark plug TQ is only about 15lbs. Most over TQ the plugs needlessly and that can be bad news. So take it easy on the installation of new plugs.

[Bernd]

just found out my next car with the 1AZ-FSE engine (D-4 direct injection) comes stock with iridium plugs . After what I read on this board, these may remain in placce for a long time. THis thread suggests 100-120k miles. http://www.toyotanation.com/forum/t94425.html
Can we expect similar mileage from Ir's fired by a single coil per cylinder?

Does the factory use antiseize? (I don't want to find out in a few years, I'd rather soon take out the plugs and add the asz.)

How I know about the Ir? I went to an Autobacs and checked the spark plug catalogs, NGK and Denso both identify the plugs for the 1AZ-FSE se as Ir plugs - for $20 apiece. And the Splitfiires catalog lists the car and engine and no SF plug for it.

Also there are no Directhits for this engine. Tinkering on the plugs may be not gainful any more, the stock plugs and ignition have been upgraded.