problem tightening spark plugs, 1995 Mustang gt w/Edel aluminum heads

sircorey · 02-25-2008

Hi,

Not sure what's going on but I was careful removing the old plugs and when I installed the Autolite 3924s in the edelbrock 5.0 heads they felt snug, then felt loose then snug then loose etc. I put a small coat of anti seize on them first and then hand tightened them to make sure they were in straight. I put on the spark plug socket to torque em down and it got a little snug and then loose, I never even got a quarter turn on them before it felt loose again

I checked the old plugs and there wasn't any shavings of metal on the plugs, I backed out the new plugs and even though there was anti seize on them I didn't see any aluminum shavings on the plugs so I doubt the threads are damaged but I just don't know why the plugs wont stay tight and I'm not wanting to take a chance on plug blowout.

Not all the plugs had this problem; only 3 out of the 8 that I tightened. The other 5 are perfect.
Has this ever happened to you guys, if so what do you suppose the problem might be? The plugs never wen't in crooked, they were easy to start and didn't grab going in. Does anti-seize cause this? Can you bust the threads on the heads that easily? I didn't go crazy on the good'ntight, never got a 1/4 turn on them after they were snug? Don't know.... Help?

Thanks

Corey

**EagleAutosports** · 02-25-2008

Just about everything on Edelbrock heads have helicoils except the spark plug holes. This sounds like there's thread damage, it isn't hard to do with spark plug holes. You could get a spark plug thread chaser and see if that helps.

snake 42 · 02-25-2008

Quote:

Originally Posted by EagleAutosports

Just about everything on Edelbrock heads have helicoils except the spark plug holes. This sounds like there's thread damage, it isn't hard to do with spark plug holes. You could get a spark plug thread chaser and see if that helps.

It could also be the plugs. Try switching the plugs that are binding into another hole and see if they still bind. If they do then there is a possibility of thread damage on the plugs or they may be out of round which, believe it or not, is not all that un-common. If the plugs are bad take them back and get replacements.