NGK spark plugs breaking.

[Killer6]

To add, I'm thinking this was just prior to Cooper Industries aquiring them, but it may have coincided with that....I'm not certain what year that occured....

 

[PRH]

Spark plugs, engine oil, oil filters, religions, air filters…

What are: “things you aren’t going change anyone’s mind on in an automotive Internet forum” Alex

 

[PRH]

My approach to the OP’s dilemma would be something where the thinking is way WAY outside the box……..

My old NGK catalog shows a GR4 plug listed for a 70-74 225ci.
I’d try a set of those…… with the gaskets, and see if they fail or not.

 

[slantsixdan]

I’d try a set of those…… with the gaskets

The metal ring washers (gaskets) do not belong on the spark plugs—whatever brand of spark plugs—in a '63-'74 Slant-6, so are you by-the-book or not?

 

[318willrun]

The metal ring washers (gaskets) do not belong on the spark plugs—whatever brand of spark plugs—in a '63-'74 Slant-6, so are you by-the-book or not?

what about the later model heads? say, the 80's. metal ring washer or still no?

 

[slantsixdan]

what about the later model heads? say, the 80's. metal ring washer or still no?

'75-up Slant-6 heads take taper-seat plugs, which never have a gasket.

 

[MOPAROFFICIAL]

I'll throw this out there for what it's worth. I believe the 30 LBFT is for the plugs with washers, so the washer gets crushed. Once you remove the washer, I don't believe I'd go down 30. I've never in my life torqued a plug down and never had issues.

I was going to say, who TF uses a torque wrench on spark plugs anyways LOL