awesome info. from a business perspective, why would they tell you 100k if it wouldnt last that long or at best last that long? potentially damage the car thus hurting the reliability reputation? as far as service goes, i always thought they over did the service interval to bring you in more often to service your car and pay more money when not needed.V6 i VTEC said:For a long time car companies just used copper plugs, because it was cheap. Copper plugs didn't have a really high life span. As cars became more technologically advanced i.e. combustion temperatures got hotter for better combustion and lower emissions, copper plugs couldn't cut it. Platinum plugs are harder than copper alloy plugs, and can with stand about 1600 degrees and last 3x longer than copper, so car companies eventually went with a platinum plug for increased spark plug life durability. Iridium plugs are even harder than platinum, so naturally they were durable. Iridium has one feature up on platinum though. Since it's so much harder than platinum the center electrode could be made micro small for a hotter spark, in turn providing even better performance and lesser emissions and last just as long as platinum. Even though platinum and iridium will out last copper, and most car manufactures have these "100,000 Mile Tune-up intervals" ... in a real world they're not gonna last that long. That's a stretch and they do it as a selling point. I would probably give them 70-80k miles.
Something new that I have noticed on the horizon is titanium plugs. I know nothing about these, so I have nothing to say about them. I guess we'll have to wait and see how these perform.
Like I said earlier...they use long intervals between major services as a key point to selling a car. Most people now want cars that don't require alot of maintenance, so that's why you see things like long life coolant, 100k mile tune ups, and 5000-7500 mile oil change intervals. This may be possible for cars that's just cruised along down the highway 90% of it's life, but that doesn't happen in a real world. I'd recommend using your better judgement on how often you service different components of your vehicle. As for faulty plugs causing engine damage, I really couldn't see that happening ... unless the plug separated and feel in the cylinder causing a piston to break. Something I have seen before though, is a plug that wasn't firing causing a catalyst convertor to melt down because of the raw fuel it was recieving.speedlife said:awesome info. from a business perspective, why would they tell you 100k if it wouldnt last that long or at best last that long? potentially damage the car thus hurting the reliability reputation? as far as service goes, i always thought they over did the service interval to bring you in more often to service your car and pay more money when not needed.
also are you saying that iridium will last as long as platinum?
if they say change at 100k but you wuold think 70 or 80, how do you know when to really change it then? decrease in performance? etc?
how bout the wires, dist cap and rotor. change that too?
Unburned fuel is going to go two places. Out the combustion chamber mostly, or down pass the piston rings as blow-by. You would have to run this engine for a loooonngg time with a fouled out plug to damage an engine, and I do mean a long time. You're more likely to burn up a catalyst convertor 1st before damaging an engine. I'm not saying it's impossible, just highly unlikely. If a person couldn't notice that thier car was running on one or two less cylinders, then maybe they shouldn't own a car.showgunz said:Denso recommends replacement at 30K. It sounds a bit too quick to replace them, but I rather not be sorry so I'll go by their recommendations. Iridium in itself may last as long as platinum, but Denso Iridium spark plugs are recommened for replacment at 30K miles.
And bad plugs can and slowly damage your cylinders. Can you imagine fouled plugs causing a lot of deposit to form in that chamber and eventually seize the piston and/or connecting rods? Believe me, you want ignitability to some degree in each cylinder. When you have plugs that don't fire, you're inputting fuel and air that doesn't get combusted. Where does that unburnt fuel and air go, hmm? Explain that and maybe I'll be convinced that the engine won't sustain damage.
Blow-by is any type of gas that escapes around the piston rings. Pistons have three rings. At the very top is the 1st compression ring, under that is the 2nd compression ring, and the 3rd is an oil control ring which is a combination of 3 rings by itself but has nothing to do with holding compression in the engine.showgunz said:True. But the blow by is usually for small amounts of fuel not burnt off by normal combustion. The gap around the piston ring is very small. When a spark plug doesn't ignite and the unburnt fuel is mixed around the cylinder, I wouldn't call that a blow by.
You're not to clear here, but I'm gonna assume you're referring to me talking about unburned fuel melting a Catalyst Convertor. You'll have to remember that when fuel is drawn in and not ignited, it's still there. So when the exhaust valve is open whatever is in the cylinder will be forced out. whether it be exhaust gases, or unburnt fuel.showgunz said:Besides, the exhaust valves are not big enough to let fuel out of the combustion chamber. The valves let out air, remember that. .
I agree with you on this, but it would take alot of driving with a dead plug to cause major wear to the piston or cylinder wall.showgunz said:And if the unburnt fuel leaked through the gap around the piston rings, believe me, your pistons won't last long.
Do it at 60k, if you don't see a service interval for it. They may last longer than that, but I've learned not to push the reliabilty of distributor type ignition systems and thier corresponding components.speedlife said:so when do you change plugs guys. my car has 52k on it. my manual doesnt say when to change the wires, dist cap and rotor