| [GMCnet] might as well change spark plugs [message #345649] |
Tue, 23 July 2019 17:59  |
Ek_Lektro
Messages: 167
Registered: March 2011
Karma: 2
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i’ve got some Bosch Platinums that look kinda burnt, last changed about 8 yrs (20,000) miles ago.
The burn might be because the distributor was gummed up, running too advanced (and for who knows how long).
((Sure, maybe these plugs could clean up OK, but a few of them look a bit borderline, with the tips looking a little pitted.
Anyway, I’m changing the cap/rotor and wires today, so why skimp on the plugs?))
The GMCMI parts digest lists a bunch of compatible plugs with .080 gap (for the ’76 455 engine).
So... should i buy a set of these and gap them at .045? .060?
or should i buy different plugs that are already gapped at .045?
Not sure if it makes a big difference, so any info appreciated, thanks!
Greg / SolarSonic / Los Angeles
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| Re: [GMCnet] might as well change spark plugs [message #345651 is a reply to message #345649] |
Tue, 23 July 2019 18:53  |
Chris Tyler
Messages: 458
Registered: September 2013
Location: Odessa FL
Karma: 7
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Check on the heat range, you may have a little too hot. Was it pinging under load?
THe original recomendations for HEI was 60 theoreticllay to help lean ignition [and in some applications a ridiculous 80 gap!] but thats hard on components.
I run 45 with a patterson setup. I believe thats wht he recommended.
76 Glenbrook
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| Re: [GMCnet] might as well change spark plugs [message #345654 is a reply to message #345649] |
Wed, 24 July 2019 01:11 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I installed a set of AC Delco #7 plugs about 15 years ago gaped at .040 which is what Dick Paterson recommended at the time. AC Delco changed supplier and he now recommends a different one made by the same supplier and the previous AC Delco #7s. I pulled a couple of plugs once just for grins and they look new. If someone does not post his new recommended plug #, I will go see if I can find it.
BTW, .040 is a lot easier on the the coil and module and no mater what plug you use I would use .040" or .045" gap on it.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] might as well change spark plugs [message #345667 is a reply to message #345649] |
Wed, 24 July 2019 11:10 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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I believe they are the NGK iridium IX.https://www.amazon.com/NGK-IRIDIUM-Spark-Plugs-7355/dp/B0043BIFZE
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
[Updated on: Wed, 24 July 2019 11:11] Report message to a moderator |
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| Re: [GMCnet] might as well change spark plugs [message #345683 is a reply to message #345649] |
Wed, 24 July 2019 16:24 |
Emery Stora
Messages: 959
Registered: January 2011
Karma: 4
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It makes a big difference. GM had recommended .080 because of some problems they were having with misfiring.
But .080 will burn up you module quicker.
Nowadays we use .038 - .040.
Emery Stora
77 Kingsley
Frederick, CO
> On Jul 23, 2019, at 4:59 PM, Ek Lektro via Gmclist wrote:
>
> i’ve got some Bosch Platinums that look kinda burnt, last changed about 8 yrs (20,000) miles ago.
> The burn might be because the distributor was gummed up, running too advanced (and for who knows how long).
> ((Sure, maybe these plugs could clean up OK, but a few of them look a bit borderline, with the tips looking a little pitted.
> Anyway, I’m changing the cap/rotor and wires today, so why skimp on the plugs?))
> The GMCMI parts digest lists a bunch of compatible plugs with .080 gap (for the ’76 455 engine).
> So... should i buy a set of these and gap them at .045? .060?
> or should i buy different plugs that are already gapped at .045?
> Not sure if it makes a big difference, so any info appreciated, thanks!
> Greg / SolarSonic / Los Angeles
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
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| Re: [GMCnet] might as well change spark plugs [message #345686 is a reply to message #345649] |
Wed, 24 July 2019 18:35 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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AC Delco R46SZ copper. No fancy platinum. (Platinum is useless as ground electrode still burns away gap widens . Only dual platinum are worth it as designed for new vehicles). Gapped at .038.
John Lebetski
Woodstock, IL
77 Eleganza II
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