Spark Plugs, Where to find them?

[SuperchargedSHOguy]

Ive blown apart Autolights in my nitrous Viper (very well tuned) and use NKG now and they hold up fine.
For the SHOs the autolights are the way to go IMO.

Jason, change out those Densos if you have not already!!! I just sent a message to Jessey to change them out if he is still running them in my old car.

 

[Titanium89sho]

Thanks for the headsup Chris. I will change them out before I drive it again. It has been parked for a while, and won't be out until next spring, but I am glad that I found this out.

 

[Lupo]

Has anybody ever tried the old technique of getting a bunch of spark plugs, and making sure that the electrode faces the exact way on each cylinder?
For example, making the electrode face away from the intake valves.
Kind of a pain, because you would have to try many different spark plugs per cylinder before you found the one that put the electrode in the proper place after the correct tightening.

 

[texantony]

Dont EVER EVER EVER EVER EVER use Densos. Densos are junk!!:cuss: I should have learned when the first 3 plugs failed on me. But no, I went ahead and installed new ones on my engine. Now I have a very expensive boat anchor I'm sorry if I recommended them in the past


I am using the same plugs Shomurph is running on his s/c sho.
autolites AR3911 (racing).
This morning they proved to withstand quite a bit and had no problems.

 

[yamahaSHO]

Jason, change out those Densos if you have not already!!! I just sent a message to Jessey to change them out if he is still running them in my old car.

I'm planning on changing them out. I haven't driven my car in a couple months, so I haven't really thought about it. I have to replace the starter (I think the original has a short) and I'll get the plugs at the same time.

Pat has used these plugs in the past and was happy with them. I'll have to make sure he's aware of the failures. Thanks guys.

 

[twr]

Guess I'll be pulling mine out too. I went with them because of Pat's experiences.

 

[yamahaSHO]

Terry, I didn't realize you were using them.

You going to be around today? I'm in town and I have some stuff for you

 

[twr]

Yeah, I'll be home around 5. Sucks - I just put them in a month or so ago. I just orded the autolites, should have them next week.

 

[SuperchargedSHOguy]

Dont EVER EVER EVER EVER EVER use Densos. Densos are junk!!:cuss: I should have learned when the first 3 plugs failed on me. But no, I went ahead and installed new ones on my engine. Now I have a very expensive boat anchor I'm sorry if I recommended them in the past


I am using the same plugs Shomurph is running on his s/c sho.
autolites AR3911 (racing).
This morning they proved to withstand quite a bit and had no problems.

Not your fault for recommending them in the past. They were supposed to surpass all the other plugs but we live and learn, some lessons are more expensive than others.

 

[SHOZ123]

How do the Autolite XPs hold up? Do they make some for the V6s?

 

[1slickRED89]

the Autolite XP for the V6 is XP3924. for the V8 it would be XP104

its a finewire double platinum, so holds up fine. for a nitrous or boosted engine it may be too hot. the XP line is really only for OE replacment, so they do not have lots of colder plugs in that line to choose from. but, you don't really need them anyway, a set would outlast a high-effort engine 3 times over. plus the required spark voltage drop you get from the finewire is about the same as a you would get from a NR plug. which is about 1,500 volts per plug or 3,000 volts for our DIS.

the coldest plug made by Autolite, that is finewire, is the motorcraft branded AGSP12FM1, its a conical seat with a resistor though.

 

[SHOZ123]

I use the XP 103s on my V8 FWIW.

 

[sho_sc]

Just for an update, while I got internet access to SHOForum:

I've been "lightly" driving around with Autolite AR3910 and it seems they are going to work out just fine. These plugs are nice, especially considering the price. The electrode is trimmed back so far that they were hard to gap, but I’m sure the spark is “nice”. For some of the comments earlier, I do believe that the AR3910s are one step colder than the AR3911.

Now a comment about the Denso plugs. Sure enough, nearly every Denso I have pulled out shows signs of coming apart. I can run them on the street using a very conservative timing curve, get on the SHO once or twice, and look at the plugs under magnification. They WILL show signs of chipping at the insulator.

 

[1slickRED89]

your right, the AR3910 is one range colder than the AR3911.

the side wire is extra thick and cut back because when you get into these really cold racing plugs the side wire becomes the hottest part of the plug, and it is more likely to preignite off of the side wire than the center electrode or ceramic body, which would normally be the case. you are giving up durability for performance though, because the side wire will have more arc erosion and will need to be periodically re-gaped. esspecally if your trying to hold it tightly to a certain gap, maybe every 20 hours of hard running or 4 weekends at the races, the gap will open a thousandth or two from erosion and will need to be nudged back in, especially with a high output ignition like ours that will fire the back three plug with a reverse polarity spark. or you can re-gap them once a year if you don't mind the gap increasing .005"-.01" a year.

 

[luigisho]

Anyone indexing their plugs or is that forced induction myth? Always wondered if that made any difference for hot spots and the like.

 

[yamahaSHO]

Not here.... Too much time involved and I'm sure the water/meth cools the 'hot spots' fine

 

[1slickRED89]

Anyone indexing their plugs or is that forced induction myth? Always wondered if that made any difference for hot spots and the like.

if you want to try it out I would stay away from steel indexing washers they sell in jegs or whatever. safer to over-buy and sort the for the clock postion you want. then post what you find!

 

[Lupo]

Anyone indexing their plugs or is that forced induction myth? Always wondered if that made any difference for hot spots and the like.

We'll see if it nets me anything tangible. I was able to index all 6 plugs by starting with 10.

 

[yamahaSHO]

I just got my AR3910 plugs today and I didn't realize they were just copper plugs. On the plus side, Summit sent me a razor with my purchase (Schick Quattro Titanium) .

 

[sho_sc]

I just got my AR3910 plugs today and I didn't realize they were just copper plugs. On the plus side, Summit sent me a razor with my purchase (Schick Quattro Titanium) .

That's all they are ... I got mine at Advanced Auto ( 1 day order) for , IIRC, $2.79. For that price, I change them out every 6 months and still come out ahead ...