Spark plugs backing out

289 - 351 cid Small Block Performance
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thrnelson
Posts: 116
Joined: Thu Sep 10, 2015 12:58 pm
Location: Binghamton, NY

Spark plugs backing out

Post by thrnelson »

I checked around the forum to see if others have had this problem and I did not see it. When I took my comet in last winter to have a new exhaust put in I was told that a few of my plugs were loose. I figured I just forgot to tighten them but I was hearing some strange noises yesterday and the plugs are loose again. One of them is so far out that it almost fell out when I touched it. The scary part is I just took it on a 3 hour round trip yesterday. It ran surprisingly well now that I see this.

Any ideas?

Trent
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popscomet
Posts: 9494
Joined: Sat Jan 01, 2011 10:19 pm
Location: Jacksonville, Arkansas

Re: Spark plugs backing out

Post by popscomet »

I betcha your using a thick wall spark plug socket and it's rubbing giving you a false sense of tightness,,,,MY comet as well as a few other times ,I've had this happen to me,,,so I took my socket and put it on a grinding whl and spun it in my hand and took just a bit off,,but like I said ,I kept spinning it so's I wouldn't end up with a flat spot,,,on a chrome socket I just took the shine off..the headers on my comet have a thick flange and will rub the socket,,you need to address this cause that loose spark plug can cause undo wear on the threads....I had one yrs ago blow out on a 55 V8 ford,,makes a heck of a sound with that compression blowing out while running down the hwy,luckly my spark plug stayed on the plug wire and I didn't loose it...I am assuming your using the correct spark plug for the head !! hope this helps....you may have to get the correct tool and chase the threads in the head,,but I doubt it those threads are pretty tough.....good luck POP
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pop/glenda

thrnelson
Posts: 116
Joined: Thu Sep 10, 2015 12:58 pm
Location: Binghamton, NY

Re: Spark plugs backing out

Post by thrnelson »

Thanks Pop. It seemed strange to me but your explanation makes sense. I will start grinding and then check all the plugs again.

Trent
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poboyjo65
Posts: 5999
Joined: Thu Oct 20, 2011 8:40 pm
Location: Camden, Tenn.

Re: Spark plugs backing out

Post by poboyjo65 »

A couple years ago I was checking the plugs & broke 2 of them on one side. :roll: I dont remember for sure what I used but it wasn't my regular socket & short extension that I had been using. I think it was one of those extensions with the tapered drive to let the socket wobble & work at an angle, & I didnt have room to hold it & turn it properly . So Now I make sure I have the right tool on the plugs.
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Johno
215-60-15 on 7x15's .... 29-15-15 on 10x15's

thrnelson
Posts: 116
Joined: Thu Sep 10, 2015 12:58 pm
Location: Binghamton, NY

Re: Spark plugs backing out

Post by thrnelson »

I have experienced a difficult fit on these plugs when I had cast manifolds. I ended up buying four different spark plug sockets.

Thanks for the tip.
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