Question on Spark Plugs!!!

[white97ex]

I worked for a guy who owns his own foreign car repair shop. He has been working on foreign cars since he was in high school. He has worked for toyota dealerships before he owned his own shop. He wont even look at a foreign car if it has platinums. He has seen platinum plugs melt the wires because they burn too hot for them. I agree with everyone that says run NGK. if the manual recommends them then use them. Just like motor oil. if it recomends 5-w30 use it. hehe. i am almost 101% sure that honda knew what they were doing when they recommended that plug for their cars

[texan]

Originally posted by white97ex
I worked for a guy who owns his own foreign car repair shop. He has been working on foreign cars since he was in high school. He has worked for toyota dealerships before he owned his own shop. He wont even look at a foreign car if it has platinums. He has seen platinum plugs melt the wires because they burn too hot for them. I agree with everyone that says run NGK. if the manual recommends them then use them. Just like motor oil. if it recomends 5-w30 use it. hehe. i am almost 101% sure that honda knew what they were doing when they recommended that plug for their cars

So this guy is trying to tell you that the electrode tip material causes such a difference in heat at the opposite end of the plug that the boots melt? Does he also sell bridges? Tip material has NOTHING to do with how hot the plug gets, that is dependent entirely upon combustion chamber temps and spark plug heat range.

[white97ex]

well i am not an ignition system guru. But, the plug could be trying to draw more current than the wires can handle and they fail. the only time that he has ever seen a honda factory plug wire fail was when platinum tip spark plugs were used...he never explained why it happened. he never once implied that the electrode tip material burned to hot to melt the wire. he just said, basically, that the only wire failures he had ever seen was cause by the use of platinum tip spark plugs

[white97ex]

oh, could someone post the link to the post where i can get my posts back. i've done it once already but for some reason i got deleted and had to re-register...thanx

[5_LiTeR_EaTeR]

Texan.... On EVERY car I don't care what make or model, but all combustion chambers will burn at 572 degrees. Thats on every single car ever made that has a internal combustion chamber excluding rotary. I have had too much bad experiences with platinum plugs. They burn way too hott. Honda didn't spend thousands of hours testing in labs and what not to find out that Platinum plugs make a difference. They don't do jack shit but end up fucking shit up. Guess how much I bought my car for? $600. a 90 CRX with a blown head gasket. I bought it did the job myself at the Garage I work at. I talked to her and she said yeah I just got a tune up done like last week then I found it out was blown. She said she had it done at percision tune (a local tune up shop) and I just shook my head at the stupidity. they put Platinum plugs in my car and fucking blew the head gasket. If you want and think Platinums are good and the best then there is no problems with me. It will give me the chance in the future to make more post because you come back on saying something in wrong with the way you car is running. I have been working on car for 5 years and am 17 now... I have the knowledge of people who have been in the business for 30 years. take it from me... you don't want Platinums. Ak any real performance shop They'll say Platinum suck ass. Go NGK... I don't know about the iridiums....

[texan]

5_LiTeR_EaTeR- With all due respect, all of that is just not true. Where you got the 572 degree number is not clear to me, except that you may have heard it from nitrous applications. It is true that nitrous disassociates into free oxygen and nitrogen at that temperature, butthat's a LONG ways away from where average combustion temps are. Think about it, when was the last time you saw an EGT reading off your average modestly turboed motor? It should be around 800 celsius (~1450 farenheit) to be in the nice safe zone for combustion temps on premium pump gas. Which is a shitload more than 572, and the reason why engines make power from converting heat energy into mechanical motion.

There are a lot of things that will significantly effect combustion temps, inlcuding but not limited to...
-VE
-RPM
-ignition timing
-compresison ratio
-fuel type
-air/fuel ratio
-combustion chamber design
-mixture homogeny
-charge stratification

Beyond that, Honda DOES use platinum plugs on some of their best engines. All 5th gen Preludes for example have them (NGK's), in addition to the new RSX and countless other cars from very reputable manufacturers (Porsche, Mercedes Benz, Jaguar, etc...). And beyond that, the only thing platinums change is the hardness of the electrode material and their conductivity. Platinum is used becuase it is so much harder than everything (besides iridium) that the electrodes don't round off for at least 50,000 miles, which makes plug changes a rare issue and performance more reliable over long periods of engine use. And to state it again, the plug temperature has everything to do with it's heat range (a design feautre) and nothing to do with it's electrode material.

So with all due respect your car knowledge, please understand you aren't the only one who knos about them. I've got about triple the time in on you in wrenching on them, and grew up with a father who built race motors.

[Someguy]

As usual Texan is right on this one. I'll see exhaust tempatures well over 1200 F with out a turbo. The flash point of gasoline will very depending on its make up, but I believe its considerably lower then 572 F, which actually has little relationship to what tempatures a combustion chamber will experience. If it wasn't you'd have a hard time lighting a pool of gas with a match, and Mr. Science doesn't recomend you try that one at home. BTW, here's a link to a wonder site which sites the approximent tempature of when nitrous oxide breaks down:

http://www.howstuffworks.com/question259.htm

Anyway the tempature in the combustion chamber is a function of how much energy is released (in the form of heat, directly or indirectly) by the burning of the fuel over time, and how rapidly the surroundings dissipate that heat, which is a function of many things including what Texan listed. The flashpoint of typical paper is 451 F, but that doesn't mean if the paper is burning its tempature is 451 F.

Anywho, most of the real hardcore guys I know actually run copper plugs. They don't last nearly as long platniums or iridium plugs (or sound nearly as sexy), but depending on the application, actually have better performance while they do last.

[fritz_269]

texan - you're conclusions are correct, but it's not technically the 'hardness' of the material that makes the difference in the plugs (no matter what marketing says...). What matters is the melting point of the metal. Here are the melting points (in Celsius) of the common metals:
Copper == 1083
Steel == 1400-1500
Platinum == 1772
Iridium == 2410

The higher the melting point, the less electrode wear you'll get.

Someguy - copper plugs are great in high-compression, boosted, high-RPM, or any other high-heat engine. Because of the wide electrode, they do a great job at conducting heat away and preventing detonation causing hot-spots. But in a normal, cool street engine, platinum or iridium plugs (in a conventional configuration) should - in theory - provide a more reliable spark because of the sharper elecrode geometry; particularly at low-voltage and/or high-RPM conditions.

5_liter_eater - I'll just say I agree with texan and Someguy. Combustion chambers burn much hotter than 572 degrees F and can vary by thousands of degrees F between engine designs. Platinum plugs of the correct size and heat range will do absolutely no damage to a stock engine. And please take it easy on the cursing, this is a public forum.

Lots of basic info on spark plugs can be found in "Fritz's Treatise":
http://www.automotiveforums.com/vbul...threadid=13950