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stripped threads in plug hole?


Guest zfan

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Hey guys Am installing long tube hooker headers in my 71 Z. Just purchased 350 sbc to replace old tired one. Shop did the swap on 350 roller motor. Not sure if they changed or messed with plugs in my rpm heads but had to pull plugs in heads to install new headers. Much to my dismay the plugs were in their very tight, 30/35 lbs torque would be my guess. This is not how I do mine. To make a long story short backing two plugs out was tough very tight, did not want to turn out. When reinstalling I had the same problem. I cleaned plugs and tried again to no avail. Bought new plugs and still problem persists. Took tooth brush and put in plug hole and gently turned and removed to find slight metal debris on brush. What do you think? Am I up S--- creek or what?

 

I must admit Im not to experienced with the stripped thread issues. Ive not had that bad luck until now, maybe.

 

zfan..Mike

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It may be time to get a Heil-coil set - for spark plugs. They come in different sizes and lengths for sparkplugs.

 

If the heads are on the motor, you might have to yank the head though. I guess if you used grease on the drill bit and tap, it might hold most if not all of the AL shavings, but it might be too risky.

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Guest Anonymous

Stripped Plugs

If you're not taking the heads off the engine,

KD tools make the thread restorer that opens up

inside the combustion chamber and rethreads from the inside out. The advantage is less chance to

crossthread the damage threads. This will work

only in cases of minor thread damage. Major damage will call for tap oversize and using thread

inserts(lengths vary). Or if heads are aluminum,

spark hole can be tig welded then retapped. I

hope this infor helps.

Sunny

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Yeah they are aluminum Edelbrock Rpm heads.

Looks like they will have to come off. Not sure but may talk to engine builder. they probably were last to play with plugs as when they put it together I would think they pulled plugs?

 

I would guess that they will try to duck responsibility.

 

zfan..Mike icon_confused.gif

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First off, I had a similar thing with one spark plug hole/thread in my RPM heads that after a couple years wasn't 'happy'. I cleaned it etc similar to what you did to no avail. Then you can make a thread cleaner by filing V grooves in the spark plug threads (crosswise across the threads) a spark plug and put some slighty grease on the threads. Gently chase it into the hole and the grooves can pickup any dirt/filings and the grease will hang onto them. I did that progressively (go as far as is comfortable/remove plug and clean it/grease it back up/go back down the hole/etc etc...) and it's been fine since.

 

I've always put either a small amount of anti-sieze OR synthetic oil on my plug threads. The synth. oil is handy being right on my dipstick whether at home or at the track and checking a plug or three and has never coked up on me like dyno juice. IF it had a plug in their successfully before and it came out without you finding a HUGE mess in the hole it's hopefully alright with only above easy efforts.

 

Good luck.

 

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Guest Anonymous

Aluminum gets very unhappy screwed into by steel plugs. Steel even gets unhappy screwed too. Ross is right, lube them threads and put a little protection on them. I pulled out prematurely on an aluminum head that had never been lubricated and stripped the ****** out of the aluminum threads. Aluminum and steel set up a chemical reaction to each other and will corrode together. Lube every time you screw spark plugs into aluminum

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