Striped Sparkplug
wiz2u
10-16-2004, 01:01 PM
Trying to figure out what is the best way to remove a striped plug.
Samw
10-16-2004, 01:15 PM
Why is it stripped? Was it overtightened, or loose?
Does it still turn?
Most sparkplug failures on the Ford "modular" engines require cylinder head removal, lots of fun.
There are several companies that sell plug thread repair kits, but you have to get the damaged plug out first.
Anit-sieze compound and a torque wrench are the ONLY way to prevent stripped threads.
Does it still turn?
Most sparkplug failures on the Ford "modular" engines require cylinder head removal, lots of fun.
There are several companies that sell plug thread repair kits, but you have to get the damaged plug out first.
Anit-sieze compound and a torque wrench are the ONLY way to prevent stripped threads.
ModMech
10-16-2004, 02:59 PM
Anit-sieze compound and a torque wrench are the ONLY way to prevent stripped threads.
That is 1/2 correct.
To QUOTE from the Ford Service manual(s):
"Install new sparkplugs DRY and Torque to the special value listed." {emphasis added}
Now, Ford lists THREE different "proper" torque values. 1) 13 ft-lbs, 2) 15 ft-lbs, and 3) 18 ft-lbs. It is generally accepted that the 13-15 ft-lb specifications ARE THE CORRECT ones. We do KNOW for an absolute certainty, that even modest OVER torquing WILL strip the threads from the cylinder head.
DO NOT, under any circumstances apply ANY coating (oil or otherwise) to the sparkplugs during re-assembly. Install the new plugs (clean and dry) into good DRY threads in the cylinder head.
Also, use a torque wrench with a rating of NO MORE than 50 ft-lbs, and at LEAST 10 ft-lbs on the lower end. An inch pound Tq wrench with a maximum rating of 200 in-lbs is the BEST. Tq to 165-175 IN-LBS.
That is 1/2 correct.
To QUOTE from the Ford Service manual(s):
"Install new sparkplugs DRY and Torque to the special value listed." {emphasis added}
Now, Ford lists THREE different "proper" torque values. 1) 13 ft-lbs, 2) 15 ft-lbs, and 3) 18 ft-lbs. It is generally accepted that the 13-15 ft-lb specifications ARE THE CORRECT ones. We do KNOW for an absolute certainty, that even modest OVER torquing WILL strip the threads from the cylinder head.
DO NOT, under any circumstances apply ANY coating (oil or otherwise) to the sparkplugs during re-assembly. Install the new plugs (clean and dry) into good DRY threads in the cylinder head.
Also, use a torque wrench with a rating of NO MORE than 50 ft-lbs, and at LEAST 10 ft-lbs on the lower end. An inch pound Tq wrench with a maximum rating of 200 in-lbs is the BEST. Tq to 165-175 IN-LBS.
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