Cooler plugs?

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cult colt

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I have a '69 A 108 van (technically an "A" body?). Anyway it's about the engine (225 slant six) I currently have the recommended plugs but when it gets to normal temperature it pings like crazy. I think I need cooler plugs but can't find part numbers for the various heat ranges. The ones installed now are champion N11Y. what cooler plugs are available and what brands ? This van tends to run hot anyway due to basic design flaws with the cooling system.Thanks for any advice.
 
You are already 3 steps colder than what is recommended. RN14YC is what is supposed to be in there. If you have ping issues you may have other issues like timing advance, vacuum leak causing a lean issue or even a mechanical issue.
 
I have a '69 A 108 van (technically an "A" body?). Anyway it's about the engine (225 slant six) I currently have the recommended plugs but when it gets to normal temperature it pings like crazy. I think I need cooler plugs but can't find part numbers for the various heat ranges. The ones installed now are champion N11Y. what cooler plugs are available and what brands ? This van tends to run hot anyway due to basic design flaws with the cooling system.Thanks for any advice.

Carbon buildup in the cylinders can cause pinging as well, but there are others as Mike explained above.

Have you pulled a plug to see what they look like?
That would be my first step, then timing checking.
 
With 3 ranges cold I can't imagine it runs well at all. It is probably carboned up from un-burned fuel. I would change the plugs to the 14yc's, make sure it runs on all 6 and drizzle some sea foam down the carb with a warm engine at 1/3 throttle or so. My cold plug issue made the 273 run rich at idle enough that you couldn't stand to be an where close to the tail pipe. It would burn your eyes.
 
Cooler plugs will not help with a cooling system problem either. In fact, they may make it worse. I agree with the others comments, the engine is likely detonating due to carbon build up, which is made worse by the cold plugs. Get the carbon build-up cleaned out, put in new plugs of the correct heat range, and it should run fine again. I'd double check the timing as well.
By the way, engines that are detonating will tend to overheat, because the boundary layer of gas gets interrupted against the cylinder head and heat gets transferred from the combustion chamber into the cylinder head and into the coolant. So it starts to overheat. The more it overheats, the hotter the engine, the hotter the end gas, the more it wants to detonate, the more it wants to overheat. It's a snowball effect. That's why an overheating engine wants to detonate and that's why engine detonation tends to cause overheating.
 
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