stripped spark plug thread
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Mountain Pass
Joined: Jan 2010
Posts: 195
Likes: 10
From: essex, CT
stripped spark plug thread
Had a plug blow out of the engine. Looks like its a stripped cross threaded problem on my 239 flat head.
Anyone know the correct threat size of the spark plug?
Were can you find a heli-coil repair kit.
The autoparts stores around here say its 14 MM..............I don't think so its a 1952 Flat head ford?
And as in most stores you get this dumb look and you walk out.
Anyone know the correct threat size of the spark plug?
Were can you find a heli-coil repair kit.
The autoparts stores around here say its 14 MM..............I don't think so its a 1952 Flat head ford?
And as in most stores you get this dumb look and you walk out.
Elder User
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From: south Fl.
Fleet Owner
Joined: Jul 2004
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From: NM
Ive heard of guys bringing the piston up to the top of the cylinder then injecting shaving cream into the spark plug hole all the way up prior to drilling and installing the helicoil. Then vacuum out the shaving cream and metal shavings. My major concern would be making absolutely sure I get the tag end of the helicoil out of there.
Fleet Mechanic
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From: Northwest
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From: Brentwood, TN
This will give you a bit of an idea of what you are looking at...
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Mountain Pass
Joined: Jan 2010
Posts: 195
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From: essex, CT
i have read a trick is to coat the tap with grease to capture the small amount of chip that chasing the thread down for a heli-coil.
Tuned
Joined: Oct 2009
Posts: 381
Likes: 74
From: Walla Walla Washington
That's clever! I've heard of people greasing the drill bit and tap, but that's not fool-proof. Yes, the tang can be an issue. Personally I'd prefer a TimeSert, but the tools for that aren't cheap, and you might need the head off to do it right. If you could get the truck to a shop that has the tools, that would be worth the trouble IMO.
B
Fleet Owner
Joined: Jul 2004
Posts: 27,298
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From: NM
Which plug is it? I'm honestly kind of surprised the threads in a c.i. head would strip without serious torque. Might be worth seeing if you can get the plug in square and if it will take torque. (20 - 25 ft-lbs)
Cargo Master
Joined: Apr 2005
Posts: 3,337
Likes: 165
From: Harpswell Maine
I agree with the time cert. I did a plug time cert in the distant past on an installed Mercedes head doing the grease in the tap flutes trick. I ran the tap in a few turns, removed cleaned regreased and tap a few more threads, repeat, repeat.
Roast em' if you got 'em
Joined: Mar 2005
Posts: 22,014
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From: Rio Rancho, NM
Good luck
Bobby