Plug readers: What would you do??

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We have to keep in mind the other bank of plugs is ok. So I wouldn’t get locked in on the usual issues.
 
19DART66 said:
RustyRatRod has forgotten one important detail in the spark plugs for the 5.7,6.1 6.4 Hemi. These plugs only fit these engines, they have a 1 inch threaded reach (instead of the 3/4 and 1/2 inch reach of the older Mopar engines) , the 03 to 08 5.7 and 05 to 10 6.1 use a tapered seat plug, the 09 to present 5.7 eagle and 6.4 Apache engines use a gasketed seat plug. My 2012 Challenger R/T came with NGK LZFR5C-11 cooper plugs, after 2012 Chrysler started putting in all of these exotic metal plugs with a bunch of new numbers( big dollars for 16 plugs). NGK made 2 plugs for the 09 to 12 5.7 the LZFR5C-11 and LZFR6C-11, and Autolite, Champion, and I think all the other plug makers only made 1 plug number to cover NGK 2 numbers. Brisk I think is the only spark plug company making different heat range plugs for the new Hemi's and they are cooper plugs for exotic metal prices.
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I haven't forgotten anything. The plug number I shared is correct.
 
If the head gasket swap doesn't work, try swapping the Holley injectors left-right to see if the bank with coated plugs changes. Could be the injectors aren't flow-matched. That is critical when fuel is controlled by a single O2 sensor.
 
Dale Davies said:
You must be an unleaded fuel newbie. Unleaded plugs show a greyish tinge, while leaded fuels left a tan color.
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Not true. Colour is mainly dependent on temperature reached at time of ignition and mixture quality and AFR of gas species. ANY time you have an AFR at the plug Richer than stoic Carbon HAS to be left over after the burn proceeds. This carbon is what coats the plugs and indicates what the AFR is at that time. The first stage of the burn is hydrogen the second is carbon. That greyish tinge is most likely exhaust residual left behind due to poor scavenging or too much overlap.

Its not the AFR of what you give the cylinder but the AFR of the "GAS" at the plug at time of ignition. You can give a cylinder a 12.5 to 1 AFR and still get a white plug because the "GAS" around the plug is still lean as a ration compared to the rest of the cylinder because you haven't converted the liquid fuel to a gas to burn in the first place.
 
Those plugs look like the center electrode isn't flat and it needs to be flat and parallel to the ground strap to fire correctly. The greater the parallel of center electrode to the strap the greater surface area for the spark to jump across the gap and a better chance the plug will fire correctly.
 
@RockinRobin I'm curious, by chance have you been cleaning the spark plugs with a wire wheel?
 
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Hysteric said:
Not true. Colour is mainly dependent on temperature reached at time of ignition and mixture quality and AFR of gas species. ANY time you have an AFR at the plug Richer than stoic Carbon HAS to be left over after the burn proceeds. This carbon is what coats the plugs and indicates what the AFR is at that time. The first stage of the burn is hydrogen the second is carbon. That greyish tinge is most likely exhaust residual left behind due to poor scavenging or too much overlap.

Its not the AFR of what you give the cylinder but the AFR of the "GAS" at the plug at time of ignition. You can give a cylinder a 12.5 to 1 AFR and still get a white plug because the "GAS" around the plug is still lean as a ration compared to the rest of the cylinder because you haven't converted the liquid fuel to a gas to burn in the first place.
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I stand by my reply. On factory engines prior to unleaded tthey tended to tan. If just slightly rich they could be brown. If the combustion temperature or plugs were hot the ceramic would be white.
Unleaded tends to turn the ceramic a grey tint.
Hysteric said:
Not true. Colour is mainly dependent on temperature reached at time of ignition and mixture quality and AFR of gas species. ANY time you have an AFR at the plug Richer than stoic Carbon HAS to be left over after the burn proceeds. This carbon is what coats the plugs and indicates what the AFR is at that time. The first stage of the burn is hydrogen the second is carbon. That greyish tinge is most likely exhaust residual left behind due to poor scavenging or too much overlap.

Its not the AFR of what you give the cylinder but the AFR of the "GAS" at the plug at time of ignition. You can give a cylinder a 12.5 to 1 AFR and still get a white plug because the "GAS" around the plug is still lean as a ration compared to the rest of the cylinder because you haven't converted the liquid fuel to a gas to burn in the first place.
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The OP is using 110 octane ' racing fuel'. Maybe that colours the plugs differently compared to regular fuel?
 
Dale Davies said:
I stand by my reply. On factory engines prior to unleaded tthey tended to tan. If just slightly rich they could be brown. If the combustion temperature or plugs were hot the ceramic would be white.
Unleaded tends to turn the ceramic a grey tint.
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Its chemistry......They still tan today. Has nothing to do with lead and everything to do with Carbon.

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Hysteric said:
View attachment 1716124385
Thats on street fuel
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Hysteric said:
View attachment 1716124385
Thats on street fuel
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Yes, unleaded street fuel. In the '70's the plug on the right in your previous post was the normal for leaded street fuels. What is the composition of 110 race fuel?
With a single plane manifold and throttle body injection that there is an imbalance between the left and right injector volumes could account for that difference.
Here is a crazy thought, could the 4 barrel throttle body be intended to have "secondary" injectors with a larger spray volume than the primaries? In that case, could the one secondary be switched with one primary, say front left to rear right? Pretty sure this is not the case but just a thought. Stranger things have happened.
 
TT5.9mag said:
Any chance you have a pic of that plug before it ran in the engine?

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On their (Brisk’s) website the pic of that plug shows a very sharp electrode and ground strap. You are nibbling the edges off of everything and that is a sign of the very beginnings of detonation. Hopefully this isnt just a stock photo they use.

View attachment 1716122516
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Is it possible the sharp edges are being removed by the wire wheel he is using to clean the plugs? He stated in this picture on page 1 that he used a wire wheel to clean the plug.

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Dale Davies said:
Yes, unleaded street fuel. In the '70's the plug on the right in your previous post was the normal for leaded street fuels. What is the composition of 110 race fuel?
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I could post many many more pics of tanned plugs on modern street fuel.........with no greyish tinge. Its no different to the people who claim modern fuels show white plugs.....

The composition of race fuel is the same as street fuels......They are both hydrocarbons it just depends on what the fuel chemist decides best suits the application. They also make about the same power.
 
These place is getting almost as bad as Moparts. Let’s see if we can go on another week about spark plugs. Lmao.
 
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