I've inadvertently mis-threaded a spark plug, thought it was in further than it was :censored:

 

How do I recover from this act of stupidity? It is only the top two threads - I think.

 

That'll teach me to be more careful!

Would this do the job?

 

https://www.machinemart.co.uk/p/cht261-spark-plug-thread-chaser/?da=1&TC=GS-040210261&gclid=CLeyreTstdQCFQ0R0wod0N8Nxg

Tap the thread perhaps with a tap & die set?

Yes, something akin to that, as I said - only a couple of threads in - so maybe a cleaning of the threads rather than a full scale re-tapping.

I would approach with caution, there is a high risk of making things worse if you are not careful.

Do you know anyone with a scope?

I think it is important to see and understand exactly what you may have done first personally.

Am I correct in saying that the spark plugs are a 14mm thread?

I would approach with caution, there is a high risk of making things worse if you are not careful.

Do you know anyone with a scope?

I think it is important to see and understand exactly what you may have done first personally.

 

This. You are more likely to just make a mess than anything else. Even if you recut the top two they will be duff threads that are more likely to allow the issue again. The only proper way to do it is to helicoil the thread. I would probably try to wind the plug in square very gingerly but that's got a fair chance to backfire on you so I wouldn't recommend that.

I had thought of this...

 

http://www.ebay.co.uk/itm/Sealey-Reverse-Action-Damaged-Spark-Plug-Thread-Tap-Chaser-Restorer-14mm-MS003/291171025832?_trksid=p2481888.c100675.m4236&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Db52800d19ff741938da3f0929706d4e5%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D291171025832&_trkparms=pageci%253A0e39b96e-4ec4-11e7-9e51-74dbd180cbad%257Cparentrq%253A980323e815c0ab6b76917483ffff6a41%257Ciid%253A1

Looks like an option.

It sure does :wink:

What a clever idea!

 

[video=youtube;-sL9jQcRZek]

Neat idea. I like the way he repaired the thread and dove straight in to put the plug back in with the ratchet! Get it started with your fingers!

 

I'd be trying to get a small tube on a vacuum in the hole to clean up the fall-out/swarf afterwards.

Neat idea. Get it started with your fingers!

 

I'd be trying to get a small tube on a vacuum in the hole to clean up the fall-out/swarf afterwards.

 

I would also advise using a torque wrench, best not over tighten the things.

We sometimes put some grease in hole with engine near tdc,

Clean thread with a tap adapt it to reach careful of piston, then we normally spin engine over with no plug to blow anything out of cylinder...

We have an engineer company come in if they need heli coil etc...

But if its 1st few threads and clean them with the right tap should be fine...allways work for us...

Had lexus is200 at work that threads came out with plugs, was heli coil and worked fine...

Hope u sort it...