Spark Plug Gap

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bad86capri
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Vehicle Information: 1986 Capri 306, Twisted Wedge heads, RPM II Intake, Anderson B3 cam, 80Lbs Siemens Injectors, MAC Longtube Headers, G-Force T5, Spec 6 Puck Clutch, Ford Racing Aluminum Driveshaft.

Spark Plug Gap

Unread post by bad86capri »

So i was reading some of the write-ups on the homepage and came across the plug gaps. I'm running TW heads with the Autolite 3924 gapped at .045". The write-up said to gap at .050". My question is im planning on switching to a iridium plug, do you recommend the same gap?
decipha
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Re: Spark Plug Gap

Unread post by decipha »

I don't recommend iridium plugs.
Apex
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Re: Spark Plug Gap

Unread post by Apex »

decipha wrote: 2021 Jun 28, 13:56 I don't recommend iridium plugs.
Is this because copper has better electrical and thermal conductivity than platinum and iridium, or is there more reasons beyond this?
bad86capri
Posts: 163
Joined: 2021 Feb 16, 10:09
Location: Knoxville, TN
Vehicle Information: 1986 Capri 306, Twisted Wedge heads, RPM II Intake, Anderson B3 cam, 80Lbs Siemens Injectors, MAC Longtube Headers, G-Force T5, Spec 6 Puck Clutch, Ford Racing Aluminum Driveshaft.

Re: Spark Plug Gap

Unread post by bad86capri »

Apex wrote: 2021 Aug 04, 13:35
decipha wrote: 2021 Jun 28, 13:56 I don't recommend iridium plugs.
Is this because copper has better electrical and thermal conductivity than platinum and iridium, or is there more reasons beyond this?
I'm curious about this as well. A good friend of mine whos been in engine building and drag racing game a long time recommended the platinum or iridium plugs over copper core. he swears by them. even has dyno tests that shown a 7-10 hp difference at the wheels. But im always open to learn more and hear different points of views on subjects like this.
034v
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2019 Explorer Sport - 3.5L Ecoboost

Re: Spark Plug Gap

Unread post by 034v »

Tight gap iridium can work, but this all goes back to coppers being "gap-able" over the P/PP/Ir plugs I'm sure. With a good ignition you should be ok if that is what you wanna run.

My 03 cobra blew out spark on the iridium's, didn't on 764's or TR-6's gapped in.

Personally I stick with 764, 103 or TR-6 on pushrods, 2v and older 4v setups.
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