Iridums or Copper?

[f00g00]

Well the choice was clear for me today. During boost my car started missing and had a bad miss at idle with some smoke coming from the tailpipe. Upon inspection of the spark plugs (Denso iridiums) the number 6's porcelain completely separated as shown in the second pic.
Put the old NGK BKR7E's back in and its running fine again.

 

[hvyman]

I like coppers. There cheap and tough.

 

[Suprapowaz!(2)]

I rock Autolite 3922's. Copper for me. They around $1.00 a piece from Rockauto.com. Whenever I need to order parts from them I make sure to add a set of plugs for the Supra, so it can come in the same box as the other part.

 

[f00g00]

Yeah Rock Auto is good and you get the cool refrigerator magnets with the cutomers cars on them.

 

[seoul4korea]

I use Ngk coppers myself

 

[Radial]

Irdium and platinum sparkplugs is one of the worlds most stupid inventions IMO. The core itself lasts forever, but everything else fails around it causing you to replace them anyway...lol, at an insane price ofc.
Copper for the win, always

 

[tlo86]

i dont touch autolite ive sold enough to say their consistency with the plugs suck, get denso copper or ngk. i dont like ordering parts online.. especially when you wait for shipping for a 1$ plug when every parts store sells em =/ just sayin. any parts store sells the fram plugs for less than 2 bucks and for 50 cents more you'll actually have a good plug.

radial thats exactly how i feel - excessive heat only speeds up the process. ive run iridiums for 8 or so years in my tundra but anything that sees boost gets copper.

 

[MNBmk3T]

NGK BKR7Es for me. Cheap as hell and work great for our cars!

 

[Poodles]

Irdium and platinum sparkplugs is one of the worlds most stupid inventions IMO. The core itself lasts forever, but everything else fails around it causing you to replace them anyway...lol, at an insane price ofc.
Copper for the win, always

Don't know your history well, do you?

While copper it a better conductor, it also wears fast. In fact, the Wright Flyer used platinum for the spark electrodes because of that very issue.

Iridiums are great, if the car is designed for it (they easily go 100K miles on modern cars that are getting them stock). Copper is cheap, hence why people tend to use them. Myself, I run NGK platinums because changing plugs sucks. Miata gets coppers because it came with them from the factory and they're easy to replace.

 

[Dirgle]

The increased ability of coppers to dissipate heat is one of the reasons they are preferred on high pressure boosted applications. On extended high power pulls the tip of platinum and more so the fine tip of iridium's can become a source of detonations and even pre-ignition. It is the reason you sometimes see cracked porcelain and damaged electrodes when used in these situations. Coppers can, by design conduct this heat away better than other materials. This has the added benefit of being able to run a heat range or two hotter copper plug if you have to deal with frequent below zero cold starts, or your tune and driving habits cause the fouling of spark plugs. The down side to this is that coppers degrade quicker than the other two especially in high energy ignition systems. Luckily they are cheap to replace.

 

[IJ.]

I had an issue at High Boost/Rpm with a misfire, only thing I could nail it down to was the fine electrode gloplugging with IR's, changed to Copper it went away, as for the OP's broken plug I'd be thinking Detonation..

 

[f00g00]

I had an issue at High Boost/Rpm with a misfire, only thing I could nail it down to was the fine electrode gloplugging with IR's, changed to Copper it went away, as for the OP's broken plug I'd be thinking Detonation..

I had just installed my in cabin manual boost controller and it was adjusted too high. Under boost it shot past 25 and had some crackling. I was mistakin about it running good. Yes the idle is fine but it also blew the pcv valve so oil smoke constantly. Went to the dealer to get a 2J valve which will be in tomorrow so temporarilly installed a landcruiser valve. Now it smokes on engine braking so I think my engine is screwed.

 

[IJ.]

Might have broken a ring land, run a comp and leakdown test on it F...

 

[f00g00]

On the way home from work this morning it was pretty smokey in boost, revving, letting off, will do a comp test this week and if its bad Ill source another motor.

 

[f00g00]

Results of compression test done engine stone cold.
1 = 140
2 = 140
3 = 135
4 = 140
5 = 140
6 = 135

#1 and #2 at first would go up and down to 0 then would hold. I'm thinking once they got oil it stayed.
Some would slowly leak but the tester I have has an oring on it and since the plugs are recessed in the head I couldn't get the best seal, only hand tight.
I know there could still be cracks in the ringland which would allow more blowby and still check ok for compression. Next step is get it to a mechanic for a leakdown test.

 

[seoul4korea]

Results of compression test done engine stone cold.
1 = 140
2 = 140
3 = 135
4 = 140
5 = 140
6 = 135

#1 and #2 at first would go up and down to 0 then would hold. I'm thinking once they got oil it stayed.
Some would slowly leak but the tester I have has an oring on it and since the plugs are recessed in the head I couldn't get the best seal, only hand tight.
I know there could still be cracks in the ringland which would allow more blowby and still check ok for compression. Next step is get it to a mechanic for a leakdown test.

I wonder if you might have blown a valve stem seal or something.

 

[IJ.]

Numbers are very low was the throttle open during the test?

Valve Stem seals stop Oil being sucked into the Intake ports and running down into the exhaust ports they have nothing to do with compression or lack of it

 

[CajunKenny]

I had just installed my in cabin manual boost controller and it was adjusted too high. Under boost it shot past 25 and had some crackling.

This isn't the first time I've heard this story... So far, they all had the same ending...broken ring land. One was on a fresh rebuild where the tuner specialized in DSM's and he ran that 7M to 21 psi on 91 octane. My buddy was not happy. Of course the tuner blamed the build.

I had a similar experience of my own; but, didn't blow anything. I had increased my wastegate pressure from 12 to 14 psi and forgot to turn down my boost controller. I knew something wasn't right when the car went sideways in third. According to the boost controller, it peaked at 22 psi on 91 octane. Luckily, I had was able to back out of it quick enough.

Pulled like a mamma jamma for about 3 seconds though! :biglaugh:


Oh...and I run cold coppers. It's more boost friendly than Iridiums.

 

[f00g00]

Numbers are very low was the throttle open during the test?

Valve Stem seals stop Oil being sucked into the Intake ports and running down into the exhaust ports they have nothing to do with compression or lack of it

No didn't hold throttle down and the engine was cold.

 

[IJ.]

Explains the low numbers then