Spark Plug threads half stripped....

[Zep--]

The middle cylinder. Just the top half of the threads are gone, i can still screw it in by hand tho, but am afraid to put the socket wrench to it to see if it will tighten up.

I've read on here about helicoils, and for that the safe way is to have the head removed..but man..I think the last time the head was off this was at the factory when they built it in '71.

So..If that's the case which I think it is, i'm worried on top of the plug thread, i'm gonna end up with some busted head bolts trying to remove the thing.

Since I still have half the plug threads (the piston side half) is there any quick fix without going the helicoil route?

I cannot take it anywhere at the moment because:
1. Trailer has no lights
2. I have no hitch on any of my vehicles.

Thanks!
Carl

 

[Zep--]

Re: Spark Plug threads half stripped....

A little more info.

If I hand tighten the stripped plug fully in then back it out, it takes 3 revolutions of the plug before it comes out compared to 4 revolutions with one of the other unstripped plug holes.

I have still not tried to put the socket wrench to it to see if it will tighten, or if it will just spin the rest of the threads off....

any suggestions?

Thanks!
Carl

 

[boatingbob]

Re: Spark Plug threads half stripped....

A little more info.

If I hand tighten the stripped plug fully in then back it out, it takes 3 revolutions of the plug before it comes out compared to 4 revolutions with one of the other unstripped plug holes.

I have still not tried to put the socket wrench to it to see if it will tighten, or if it will just spin the rest of the threads off....

any suggestions?

Thanks!
Carl

Well my honest opinion is to try to snug that plug in with the wrench. It has to be seated properly. if it does great if not it's heli coil time. Yes you need to remove the head to put a heli coil in. If the head bolts are really tight you could try tapping them with a hammer to try and jar the threads loose. Hope this helps. If anyone else has any ideas please help out.

 

[Zep--]

Re: Spark Plug threads half stripped....

If I hand tighten it..how much further should I try to tweak it with the wrench? Any Suggestions for that?

Thanks!
Carl

 

[Zep--]

Re: Spark Plug threads half stripped....

I was hoping that with that amount of thread left there may be some way to strengthen the thread I still have in the head..some kinda Magic Spark Plug Ointment or something.

Thanks!
Carl

 

[boatingbob]

Re: Spark Plug threads half stripped....

If I hand tighten it..how much further should I try to tweak it with the wrench? Any Suggestions for that?

Thanks!
Carl

I'm not sure on exact torque, but I usually hand tighten then start to tighten with the wrench, I tighten until it's snug.

 

[rickdb1boat]

Re: Spark Plug threads half stripped....

If the threads are shot, look for the plug to come out on it's own. Not a good thing at full throttle. Best to pull the head and get it fixed.....

 

[iwombat]

Re: Spark Plug threads half stripped....

I've had luck before with loctite thread repair in the plug hole. A very temporary solution, but maybe worth a shot if you've got marginal threads. Won't work for totally gone threads though.