Sparkplugs!

[74 challenge]

I am trying to get my order together to take advantage of some Black Friday Deals (thanks America!) and had a question about sparkplugs because my car is in storage right now and cannot pull a plug to see what ones I am running.

What is a decent plug? I think it was Chryco that suggested some Champion plugs awhile ago and they were working awesome before my carb fouled them up. They were fairly cheap too.
 
I was thinking about these ones: http://www.summitracing.com/parts/cpn-3405

it's a 318 with some taylor plug wires, accel coil, edelbrock intake and otherwise pretty stock.

[Chryco Psycho]

I would use either RN12YC or RN14YC Summit is using a different part# 3403 for example so I am not sure if it is correct .

[cudabob496]

lotta folks like NGK

[AARuFAST]

Champion copper for Mopars  Use a hotter plug if fouling.

[cudabob496]

Champion copper for Mopars  Use a hotter plug if fouling.

from my experience, if plug fouling, its due to something else other than the selected
heat range of the plug.

[jimynick]

from my experience, if plug fouling, its due to something else other than the selected
heat range of the plug.

You're right, but the hotter plug will help crutch those loose valve guides and/or rings for a while. 

[Cudaragtop]

RN12YC in my 418 stroked 340 

[cudabob496]

You're right, but the hotter plug will help crutch those loose valve guides and/or rings for a while. 

yep, at that point, whatever helps!

[whitewatersky]

i pulled mine yesterday after it was missing

very black

I just put NGK 2828 / BPR5EY in and it's running very nicely

Converter shows Champion RN12YC to be equivalent, like Chryco Psycho recommended.

last set were DENSO W16EXR-U which show as another like set

Mine is running SUPER rich but we'll see how these go

need to keep fine tuning the carbies tho...

[Finoke]

You're right, but the hotter plug will help crutch those loose valve guides and/or rings for a while. 

How is the heat range of a plug designated? I finally got the jetting of my carbs close to where it should be for my car other than tuning by O2 Spenser.  I never really understood how a plug can be hotter and how to tell if one plug is designated hotter than another.

[Chryco Psycho]

The distance from the electrode throught the ceramic back to the steel body of the plug determines hot hot the plug will stay , shorter distance & the heat is easily dissapated to the head longer distance more heat is retained

[Finoke]

The distance from the electrode throught the ceramic back to the steel body of the plug determines hot hot the plug will stay , shorter distance & the heat is easily dissapated to the head longer distance more heat is retained

Thanks Chryco that makes sense. So how do you select a plug for any given engine. Is there a designation for the degree of heat from plug to plug that will fit the same engine?

[Chryco Psycho]

too hot will cause detonation
too cold will not burn off the contamination & foul

[Finoke]

too hot will cause detonation
too cold will not burn off the contamination & foul

Excellent, thanks

[barnett468]

Thanks Chryco that makes sense. So how do you select a plug for any given engine. Is there a designation for the degree of heat from plug to plug that will fit the same engine?

I run all the engines I build at 185 degrees . 195 degrees and higher can promote detonation, especially in hot climates.

I typically use the stock heat range in engines with around 160 psi of cranking compression . If it is higher than that, I will often drop down to the next coldest plug . I rarely use plugs that are 2 steps colder than stock.

I also set the timing "curve" so it is optimal for each engine . Insufficient timing can cause hot running conditions.