so i need some help :O

[angrychickens]

i just put in a new ebay downpipe on a s14 ka na , and the plug bolt that goes where the secondary o2 sensor is supposed to go wasnt tighted enough when i turned the car on and drove down the street and it popped out, does anyone know the size of this plug, is it 18mm, is that like a standard size. and if so can i get one at a local muffler shop.

also on a side note the hole is way to big for the o2 sensor, is there an adaptor or do i need to weld a bung, or get a bigger o2 sensor or should i just use the plug and cut the secondary o2 sensor off.


the middle bolt in this pic


thanks for any advice