Spark Plugs AGAIN!

[Joe Lynch]

MJ--BNASPLT is right!! DON"T run those platinum plugs with the juice!! And don't run a warmer plug if it runs fine with the 12s on the street. Put in a set of AWSFA-12C or the IT22s before the next dyno session.

Joe

 

[maoun]

Originally posted by BNASPLT
In your instance I'd definitely go IT22, and depending on what boost level you have, you should use a gap of .032 to .038.

okay, so i'm running just the stock boost....so what gap? i'm guessing towards the lower .032 or .034??

thanks again!
marwane.

 

[BOOOOST]

Originally posted by maoun
okay, so i'm running just the stock boost....so what gap? i'm guessing towards the lower .032 or .034??

Marwane, I fully believe you'll get away with .038 easily. These plugs are so easily changed, so if that doesn't work you can always gap them down.

Remember, Densos are delicate to change, so you must use the proper tool to gap them. NEVER EVER EVER use a coin gapper. That will break the tip almost every time. This is the proper gap tool to use (wire type guage):

I would check the actual gap with feelers, though. Doing it this way is important.

Here's some info from the Denso FAQ:

Q. Do I need to set the gap?

A. Generally, no. The DENSO Iridium Power plug comes pre-set with a protective sleeve over the firing end, to protect the gap from accidental alteration. DENSO Iridium Power’s ultra-efficient firing power compensates for normally recommended gap settings that are smaller than the pre-set value. In the cases of vehicle modifications (nitrous, turbo-chargers, super-chargers, high power ignition systems, etc.), some adjustments may be desired. Or, if you prefer to remain consistent with factory specifications, you may adjust. However, please be careful not to place any stress on the fine center electrode during adjustment. You could accidentally break off the very hard, and therefore brittle, tip.

Remember, though, that although they say they come pre-gapped, it will be rare that they are all the same gap, from personal experience, and many other's experience.

 

[maoun]

thank you very much! i'll gap them to .038...how will i know if it's "not working" too well? i will order them and the wire type gapper

thanks
m.

 

[Jim Vaccaro]

Originally posted by maoun
thank you very much! i'll gap them to .038...how will i know if it's "not working" too well? i will order them and the wire type gapper

thanks
m.

I gapped my Denso's @ 38 and with 13lbs boost it runs awesome..no spark blowout and good idle..


jim v.

 

[94SVT Coupe]

Originally posted by BNASPLT
Yeah, I should have clarified that statement. I'm thinking "Cobras" in general here. I just cannot see where there would be any significant gains in doing such, and do not like the fact that they can raise the plug in the cylinder, which allows less thread depth (this is especially an issue on the pre-'03 2v's where they only had approx. 3 to 4 threads to work with. There are MANY a cases of Lightnings and Harleys spitting plugs out because of the poor thread depth they have (luckily Ford has decided to fix this on most of the '03s).

OK, and the big question. Does the 03 Cobra only have 3-4 spark plug threads? I've been trying to find out, but nobody seems to know or is willing to look. Might have to look myself I guess.

 

[ntechnic]

Today I fiddled with my stock plugs. They're the AGSF22FM1's. On the dyno, there were signs of blowout above 5,500, idle wasn't bad, but it did feel a little rough at top end.

Gap as they came out of the car was >0.050 on 7 of 8 plugs! I also noticed that the Autolite design basically shrouds the center electrode. If you look at the photo in the first post of this thread, you can get a hint of it--the angle of the photo actually doesn't show just how much the ground electrode juts out beyond the OD of the center electrode. With the TR6's you can see that the end of the ground electrode is just about justified to the edge of the OD of the center electrode.

So I got out the small die grinder, and the gap tool. I cut the ground electrodes back to unshroud the spark. Quite a bit of metal to remove actually, the dang spark was all but hidden. I rounded the ground electrodes a little, and made sure all edges were radiused and smooth. I used to do this on race cars back in the day when all plugs sucked, no matter what brand.

I gapped them to .035-.038 and put them back in. HUGE difference. The Cobra idles glass smooth now, every bit as smooth as my Navigator. I mean, "Is it even running?" smooth. And the top end is just as smooth, engine pulls a little harder, revs a little quicker, and did I mention that the top end is smooth?

So I'm wondering how much of the TR6/Denso advantage is due just to having an unshrouded spark? Oh well, I'm very happy about the results...and can't beat FREE for price.

BTW, you don't have to have the heads off a car to index the spark plugs. If you know the head design, you know where the valaves are and where you want the plugs to point. You just make a small mark on the plug's insulator were the ground electrode points, and start swapping in plugs until you get one that points where you want it to.

 

[JP DEMOLET]

Edited by L.L. Cut it out. :rollseyes

 

[mjchip]

Originally posted by Joe Lynch
MJ--BNASPLT is right!! DON"T run those platinum plugs with the juice!! And don't run a warmer plug if it runs fine with the 12s on the street. Put in a set of AWSFA-12C or the IT22s before the next dyno session.

Joe

Thanks guys BUT I've been running NGK BR7EFS plugs since I installed the nitrous and upped the boost. They are copper plugs with stock heat range. I would never run platinum plugs with nitrous or very high boost, that's just asking for problems IMO.

MJ

 

[Joe Lynch]

Well in that case..........as you were!

Sorry, I just had a panic attack thinking you were running cool but platinum plugs. The ones you are running alredy are equivalent to the Motorcraft AWSFA-12C. I think.

So........go test that thing.

Joe

 

[BOOOOST]

WHEW, me too Joe Ain't MJ, let's see you slam dunk that mofo and come up with some vicious times!

Hey, how did this weekend turnout? Yah or nah?

Later!

 

[f4sfed]

Okay! You all lost me! What about the Platinum-Iridium Alloy in the AGSF12FM1's? Are these bad plugs to run in our modded cars (2.93 pulley, Basanni exhaust, etc)?

 

[03DOHC]

Originally posted by 94SVT Coupe
OK, and the big question. Does the 03 Cobra only have 3-4 spark plug threads? I've been trying to find out, but nobody seems to know or is willing to look. Might have to look myself I guess.

It has more. Here's a pic I just took.

 

[BOOOOST]

Originally posted by 94SVT Coupe
OK, and the big question. Does the 03 Cobra only have 3-4 spark plug threads? I've been trying to find out, but nobody seems to know or is willing to look. Might have to look myself I guess.

Actually, he's right in his assumptions. Although the sparkplugs have about 10 threads, only about 4 of them are used in our heads. Luckily, we do not have the blow out (not spark, I'm talking about them stripping and popping out from cylinder pressure) issue that the pre-'03 2V heads have.

 

[2F2F]

f4sfed: Good to see you in this thread =>)

 

[J. Mihovetz]

OK, here's the bottom line. Denso Iridium plugs IT 20 up to 12 psi IT22 for 12-16 psi and IT 24 for more than 16 psi boost. This is the final answer in spark plugs as I have tested them all in the real applications as welll as an MSD spark plug chamber. When someone else on this board can make over 1550 hp with a 4.6 then there might be something to discuss , until then followthese simple guidelines and you can't go wrong.

John Mihovetz

 

[f4sfed]

Originally posted by ox03
f4sfed: Good to see you in this thread =>)

Thanks. I figured I'd give you a break from me. ;-)

...and yet still no one has answered the original question. What about the Motorcraft Platinum-Iridium Alloy plugs?

 

[BOOOOST]

Originally posted by J. Mihovetz
OK, here's the bottom line. Denso Iridium plugs IT 20 up to 12 psi IT22 for 12-16 psi and IT 24 for more than 16 psi boost.

You got it! It's what we've been saying for quite some time now. Thanks for reiterating that.

As for the rest of your post... :rollseyes

 

[BocaCobra]

Well I still have my stock plugs in and dont feel a problem as of yet...With my mods and hard driving how often do you guys suggest changing out the plugs?
Thanks

 

[03DOHC]

Originally posted by J. Mihovetz
OK, here's the bottom line. Denso Iridium plugs IT 20 up to 12 psi IT22 for 12-16 psi and IT 24 for more than 16 psi boost. This is the final answer in spark plugs as I have tested them all in the real applications as welll as an MSD spark plug chamber. When someone else on this board can make over 1550 hp with a 4.6 then there might be something to discuss , until then followthese simple guidelines and you can't go wrong.

John Mihovetz

John, my IT20's are headed back your way and George is sending me the IT22's in their place.

Not sure if that last comment was really necessary......then again, I am taking your advice, so I concede that you know more than I on this subject. There you go.