Real quick spark plug question...

[smark]

From searching I see that I should get either Denso or NGK plugs when I do my tune up (just got the 85 P Type on Thursday) to replace the spark plugs, oil, antifreeze, etc.

One thing I couldn't find is any thoughts on standard copper Denso (1.69 at Autozone) vs. the platinum Denso (6.99 at Autozone).

I have no problem paying for the platinum if it is the best for the car and has more benefit than just not changing them for another 30,000 miles as I usually replace my plugs about once every year or so since they are so cheap (I run copper's in my Bronco II). The P-Type has 212K miles on it now and I don't expect to put more than 7,000 miles on it at the very.. very most in a year.

[SupraWes]

If youre already used to changing plugs once a year then you might as well use the copper plugs in the Supra too. They seem to work the best for me and several other members here.

[Phoenix]

Platinum last longer than copper.
Copper is higher performance than platinum.
Iridium is as high performance as copper and lasts as long as platinum and is the most expensive of the three.

I'd go with copper. Changing plugs more often is not necessarily a bad thing. You can use your plugs to diagnose the health of your engine.

[lechner]

Does it bother anybody that Toyota insists on platinum for these cars? Can anybody think of any reason for that other than just to extend service intervals?

[Phoenix]

Does it bother anybody that Toyota insists on platinum for these cars? Can anybody think of any reason for that other than just to extend service intervals?

LOL. :lol: No Lechner, that's the only reason!

[Dave A.]

Does it bother anybody that Toyota insists on platinum for these cars? Can anybody think of any reason for that other than just to extend service intervals?

LOL. :lol: No Lechner, that's the only reason!


I could be wrong, but I suspect that Toyota specifies the platinum plugs for a design reason. The individual components of the ignition system are probably all carefully matched together to provide the best service life and performance of *all* of the ignition system components. The resistance value of the platinum plugs may be optimized to help get the most bang for the buck while minimizing wear and tear on other parts, like the cap, rotor, and plug wires. Less arcing within the distributor cap from using the proper resistance plug for example.

[StanS]

finally hoppyjim has something good to say (if u can afford it). he recommends using iridium plugs for lifelong trouble free operation (assuming u don'y advance the timing from stock).

Neither autozone or strauss in nj carry the denso or ngk stock plugs. what a pita.

[Phoenix]

Does it bother anybody that Toyota insists on platinum for these cars? Can anybody think of any reason for that other than just to extend service intervals?

LOL. :lol: No Lechner, that's the only reason!


I could be wrong, but I suspect that Toyota specifies the platinum plugs for a design reason. The individual components of the ignition system are probably all carefully matched together to provide the best service life and performance of *all* of the ignition system components. The resistance value of the platinum plugs may be optimized to help get the most bang for the buck while minimizing wear and tear on other parts, like the cap, rotor, and plug wires. Less arcing within the distributor cap from using the proper resistance plug for example.

Heres what I see Dave ....could be....I suspect... are probably.....
Many of those decisions are made by bean counters and not by engineers. I havn't heard of copper plugs burning out the ignition system. Although, if you've heard otherwise I'd like to hear. 8)

[smark]

finally hoppyjim has something good to say (if u can afford it). he recommends using iridium plugs for lifelong trouble free operation (assuming u don'y advance the timing from stock).

Neither autozone or strauss in nj carry the denso or ngk stock plugs. what a pita.

You can get Denso Iridium plugs via the Autozone website for I believe 12.99 a pop.

[Phoenix]

finally hoppyjim has something good to say (if u can afford it). he recommends using iridium plugs for lifelong trouble free operation (assuming u don'y advance the timing from stock).

Neither autozone or strauss in nj carry the denso or ngk stock plugs. what a pita.

You can buy the NGK's direct from their website www.ngk.com

[StanS]

just went to ngk.com. they don't have (i couldn't find) a plug for 5mg but they have plug for 7mg with same gap. 7mg they have BCPR5EIX-11 (Indium) and BCPR5EP-11 (platinum). The 5mg plat plug is BPR5EP-11.
What does the extra C mean in the 7mg plug? Will the iridiums work correctly in a 6mg?

[Dangerous Ken]

Go to sparkplugs.com

Eventually, from 'Automotive' you get to 2.8L 5mge.

Iridiums for $6.95 each.

Ken

[smark]

I only saw Denso Iridiums for the 5 and they are 11.99 each.

[Phoenix]

just went to ngk.com. they don't have (i couldn't find) a plug for 5mg but they have plug for 7mg with same gap. 7mg they have BCPR5EIX-11 (Indium) and BCPR5EP-11 (platinum). The 5mg plat plug is BPR5EP-11.
What does the extra C mean in the 7mg plug? Will the iridiums work correctly in a 6mg?

Are you talking about NGK Coppers? Only platinums and iridiums are listed as being for the MkII. If you want copper you just need the part no.# If its NGK platinum or iridium you're looking for then I just saw them both there.



:3gears:

[StanS]

platinum and iridium. please post web page cause i got no plugs for 5mg. shouldn't we use 7mg plug for 6mg engine?

[Phoenix]

http://www.ngk.com/results_app.asp?AAIA=1278413

[StanS]

thanks. they have nothing listed for 85-86 supra.

[Phoenix]

No problem 8)

[Dave A.]

finally hoppyjim has something good to say (if u can afford it). he recommends using iridium plugs for lifelong trouble free operation (assuming u don'y advance the timing from stock).

Neither autozone or strauss in nj carry the denso or ngk stock plugs. what a pita.


Copper core plugs have been around for ages and are still a popular choice for high performance engines.

IIRC, Platinum plugs came on the scene somewhere during the early 1980's and this could be why Toyota decided to make use of a good thing and incorporate the newer technology into their ignition systems of that era. But, I'm not an engineer and can't prove any of this so it's all pure speculation on my behalf. Maybe Hoppyjim could elaborate on this?

Iridium plugs take the technology of the Platinum plugs one step further. They're expensive, last longer, and will last forever if you don't abuse them. The tips of Platinum and Iridium plugs can become brittle and more susceptible to damage from preignition and detonation. But all considered, we have to remember that the Iridium plugs came to be after the 1980's. That makes me wonder if Toyota would have used this technology earlier on in the 1980's as a replacement for the platinum plugs. Food for thought anyway. :-)

[SupraWes]

Get the BPR5EY stock #1233 plugs, its is a more commonly stocked plug, the only difference is it needs to be regapped before you install them, but you are checking the gap before install anyway right?

[StanS]

just found this site with lo prices for spark plugs
http://www.clubplug.net/retail_iridium_ngk.html

[RedP85]

just found this site with lo prices for spark plugs
http://www.clubplug.net/retail_iridium_ngk.htmlJust ordered some IX there.
This is a US and a Canadian site to it. No duties nor exchange rate surprizes there. :D