Iridium spark plugs

**fastbuff** · 11-28-2006, 05:03 AM

hi is anyone here running the AC delco iridium spark plug i know they come gap at 040 do we have to change the gap or not and what gap do our cars use im basically stock
Thanks

**MattZ28** · 11-28-2006, 05:57 AM

Should be fine. I think stock gap is like 0.44. My NKG's came pre gaped and I delcos should be the same.

**Fedge** · 11-28-2006, 07:49 AM

Originally Posted by fastbuff

hi is anyone here running the AC delco iridium spark plug i know they come gap at 040 do we have to change the gap or not and what gap do our cars use im basically stock
Thanks

you know...i have the same plugs and changed it to the stock .060 gap...wonder of that's why my power is down. i don't know shit about spark

what happens when the gap is too wide?

**fastbuff** · 11-28-2006, 08:00 AM

Hey i just got an e mail from AC delco and they told me not to change the gap on the spark plugs

**Fedge** · 11-28-2006, 08:04 AM

Originally Posted by fastbuff

Hey i just got an e mail from AC delco and they told me not to change the gap on the spark plugs

oh crap. wonder why they tell you on teh box to follow factory specs?????? ugh. changing the plugs is a bitch in these things and i did them when the motor was out of the car!

**Fedge** · 11-28-2006, 08:11 AM

just got off the phone with them. I'm NOT happy at all. now i hafta regap all of my plugs. crap. they need to change the directions on the effing package from 'follow factory specs' to DO NOT GAP

**Too Fast** · 11-28-2006, 03:49 PM

Correct. Iridium or platinum plugs should never be re-gapped. Just inspect them to make sure they have not been damaged on the electrode end during handling.

**Fedge** · 11-28-2006, 04:48 PM

Originally Posted by Too Fast

Correct. Iridium or platinum plugs should never be re-gapped. Just inspect them to make sure they have not been damaged on the electrode end during handling.

it still bothers me that right on the box it said to gap to factory specs, but then contradict themselves by telling me to keep it at the pre-set gap. well, that was a 60 dollar lesson learned. i pulled a plug and it was ooglay. I'm just gonna put the Delco Plats in there and call it a day...till I go FI

**Steve Crowe** · 11-28-2006, 08:25 PM

I'm not a big fan of Iridium plugs, I still prefer the AC 41-9xx series properly gapped or, if you're highly modified, these engines do tend to like Autolite plugs.

Somewhere I have a reference to the AC heat ranges, if I recall it goes like this:

41-921 = 4
41-932 = 3
41-919 = 2-1/2
41-913 = 2

The numbers have changed on some of these but they can still be found if you call around. The 41-932 are a good all-around plug set at 0.060

**Fedge** · 11-29-2006, 08:56 AM

thanks for the info...i'll pick up the 41-932s Friday morning

**Orange SS** · 11-29-2006, 10:07 AM

Originally Posted by Steve Crowe

I'm not a big fan of Iridium plugs, I still prefer the AC 41-9xx series properly gapped or, if you're highly modified, these engines do tend to like Autolite plugs.

Somewhere I have a reference to the AC heat ranges, if I recall it goes like this:

41-921 = 4
41-932 = 3
41-919 = 2-1/2
41-913 = 2

The numbers have changed on some of these but they can still be found if you call around. The 41-932 are a good all-around plug set at 0.060

colder steps ?

**Steve Crowe** · 11-29-2006, 12:32 PM

Yes, on GM #s the lower is the colder, in other words I wouldn't run 41-913 in your engine unless you really push it on a regular basis.

The 41-932 is similar in heat range to an NGK TR5 but it has a wider "cleaning range" so it tends not to foul out if you end up driving in a lot of heavy traffic, likewise it'll put up with spirited driving.

I'll find that chart when I get time, kind of interesting. Matter of fact there's an entire discussion on this one of my past partner's worked up on plugs, you'd be surprised at how poor some are and how bad some cross references tend to be.