I'm installing plugs on my 67 289. How much torque on the plugs? My manual says to check the tune up specs table but that only lists plug type and gap. Generally, I torque plugs to 12-15 ft/lbs.

Also, the manual does not say anything about dielectric grease or anti-seize. Should either of these be applied?

Thanks,

 

Usually the spark plug box says how much. I know autolites are 15-18lbs. Also some people would advise against anti-seize but I would prefer anti-seize over having a spark plug break inside my head. Also I would for sure use dielectric grease. I have ruined a good set of spark plug cables trying to pull off the boot from the spark plug.


You will get many answers on the use of these

 

I torque my plugs the german way: gut-en-tite. Honestly, until they're snug, then maybe a quarter turn more. They just need to keep from rattling out. If you have later style heads that use crush washers on the plugs instead of a tapered seat, you'll have to turn it a bit more past snug.

If you have aluminum heads, use copper anti-sieze. I never had an issue getting plugs out of my old cast iron heads without anti-sieze, but dissimilar metals will corrode quickly, especially with the application of heat. Anti-sieze will prevent this, and the Permatex copper type will stand up to the heat.

 

same here. never knew there was a german way and that's being german :-]

 

I am always a little nervous about putting in new spark plugs because it feels like they are going to strip in an aluminum head before they get good and seated. I guess that is the crush sleeve action. I always use anti-seize and never have a problem getting them out. As said above, this is important when running aluminum heads. I usually just turn-til-tight because I have to use a multiangle socket neck to get on the spark plugs which does not lend itself to using a torque wrench. As for dielectric grease, I am a big fan and use it liberally to help get the plug seated good on the plug.

 

On an engine with iron heads it's not critical and needs no compound of any type on the threads. Just make sure that they're tight.

On aluminum heads it's a totally different kettle of fish. On those you need to use a VERY thin coat of copper based anti-sieze ON THE THREADS ONLY and then torque 13-17 ft/lbs.