Spark plug hole inlet diameter

[El Cuervo]

Hey guys whats up!! Question here. Does someone know the inlet diameter of the spark plug holes?? I was doing some work on my car yesterday. I'm re-doing my valve seals and different cams and such. Well upon my valve spring compressor, one of the bolts that holds it in place slid off. I found the bolt. It landed on the head by one of the springs. The washer however. I can't seem to find it. So I'm thinking that it might've fallen through the spark plug hole and into the combustion chamber of cylinders 2 or3. I tried using a long magnet but couldn't find anything. So now I might have to buy an endoscope or a barescope to see if I can stick a small camera in there. Thats why I want to know the inlet diamete of the spark plug holes where the spark plug threads into the head. It didn't go into the oil wells because those are covered.

Thanks guys.

 

[GRAVEDIGGER]

1/2 inch

 

[El Cuervo]

Thank you very much gravedigger!!

 

[GRAVEDIGGER]

You're very welcome and good luck finding that damn washer!

 

[El Cuervo]

Thank you very much GRAVE!! I just found the washer today. I was on the floor behind one of the jack stands. Wow! what a relief.