Spark plugs different diameter sizes

[a23zelaya]

So I’m having this issues where these spark plugs are the same part number and everything but if you look closely at the thread diameter one is thicker than the other. The thicker diameter spark plug only threads into one cylinder while the thinner one would thread to all other 3 , idk I’m new to the automotive world and I just need help I’ve been looking everywhere for the specific plug but had no success

 

[a23zelaya]

So I’m having this issues where these spark plugs are the same part number and everything but if you look closely at the thread diameter one is thicker than the other. The thicker diameter spark plug only threads into one cylinder while the thinner one would thread to all other 3 , idk I’m new to the automotive world and I just need help I’ve been looking everywhere for the specific plug but had no success

Honda civic 2000 dx d16y7

 

[nd4sped]

Can you provide a photo from the top down looking at the electrode.

I have a bad suspicion but I'm going to hold that comment until I see the next photos.

 

[a23zelaya]

Ima away from the car but can you tell me your suspicion? I’ve been doing some research and the only way this would happen if the previous owner stripped the thread and had to rethread it but then again I’m completely clueless on the topic

 

[a23zelaya]

 

[a23zelaya]

So upon further investigation the plug has something called an insert! So that’s all it needed , previous owner stripped the plug hole and rethreaded it , learning new things everyday

 

[nd4sped]

That sir is a helicoil, that is BAD NEWS!

 

[nd4sped]

So upon further investigation the plug has something called an insert! So that’s all it needed , previous owner stripped the plug hole and rethreaded it , learning new things everyday

Unfortunately this is exactly what I suspected.