I've never had to deal with this before. One of the spark plugs on my Volvo 740 came out with more effort than I'm used to. Of course when I try to hand start the new one, it only wants to go in crooked. Looks cross threaded. I've tried multiple plugs, so it's not the plug itself.
To top it off the plug wire also was damaged so I'll be replacing that.
What's the Hive's best method of fixing a bunged up plug thread?
You could try a tap of that size.
They sell a spark plug thread clean-up tool. Every auto parts store has one. If that doesn't work, then there are heli-coil sets specifically made for that. HINT: Put the motor with that cylinder at the bottom (start) of the compression stroke, fill the cylinder with cheap shaving cream. Do your work. Crank the motor and the metal shavings (and shaving cream) will blow out the hole.
There's a back-tap that is made for this. It is split and can be expanded, so you put it in, expand it, then unthread it.
Yeah, I've got a thread chaser but just not sure if I should try it or get the back tap and do that instead
I've used these with success:
http://www.amazon.com/Helicoil-5334-14--Thread-Thread-Repair/dp/B0002SRF4O/ref=sr_1_1?s=automotive&ie=UTF8&qid=1464539016&sr=1-1
Dr. Hess wrote: They sell a spark plug thread clean-up tool. Every auto parts store has one. If that doesn't work, then there are heli-coil sets specifically made for that. HINT: Put the motor with that cylinder at the bottom (start) of the compression stroke, fill the cylinder with cheap shaving cream. Do your work. Crank the motor and the metal shavings (and shaving cream) will blow out the hole.
Is it a turbo? I dunno if I would want to blow the shavings through the turbine...
This engine is N/A
codrus wrote:Dr. Hess wrote: They sell a spark plug thread clean-up tool. Every auto parts store has one. If that doesn't work, then there are heli-coil sets specifically made for that. HINT: Put the motor with that cylinder at the bottom (start) of the compression stroke, fill the cylinder with cheap shaving cream. Do your work. Crank the motor and the metal shavings (and shaving cream) will blow out the hole.Is it a turbo? I dunno if I would want to blow the shavings through the turbine...
Why would it matter if its turbo or not?
If he does what Dr Hess says, then all valves should be closed and the only way out is the sparkplug hole.
Is it a four stroke?? 
Knurled wrote: There's a back-tap that is made for this. It is split and can be expanded, so you put it in, expand it, then unthread it.
Who makes this? Link?
Ugh, I found it at Jeggs, and Amazon has the cheap version.
I think Im going to have to buy one just to have in the tool box!
Knurled wrote: There's a back-tap that is made for this. It is split and can be expanded, so you put it in, expand it, then unthread it.
I didn't know that was a thing until just now! Outstanding! I'ma gonna get me one of those. They also make a size for O2 sensor holes, I could have used that a few weeks ago.
The back up tap is a good tool. Without that, any tool or plug you use is going to have to be forced back into the proper line. Sometimes its only a half thread or so that's screwed, so line the socket and extension up with the other plugs, and force it to the right plane as you screw it in. Only go a half turn at a time until you are sure its headed in parallel with the other plugs.
Slippery wrote:codrus wrote:Why would it matter if its turbo or not? If he does what Dr Hess says, then all valves should be closed and the only way out is the sparkplug hole. Is it a four stroke??Dr. Hess wrote: They sell a spark plug thread clean-up tool. Every auto parts store has one. If that doesn't work, then there are heli-coil sets specifically made for that. HINT: Put the motor with that cylinder at the bottom (start) of the compression stroke, fill the cylinder with cheap shaving cream. Do your work. Crank the motor and the metal shavings (and shaving cream) will blow out the hole.Is it a turbo? I dunno if I would want to blow the shavings through the turbine...
Oh, I misunderstood, I thought he meant to put the plug back in before cranking and the foam was just to stop the bits from falling down into the rings. Isn't the 740 engine a DOHC design with deep spark plug wells? Seems like cleaning up the foam after you're done would be hard.
No the 740 is an sohc head, 8valves in this case. The plugs are right on the surface, but angled back towards the firewall, which looks like it will make tapping on the right angle difficult. Think I'll order a back-tap.
In reply to bastomatic:
Well most are 8v...they did make a few handfulls with a dohc
Back-tap for the win. Thanks guys
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