O2 Bung

[Jap GT300]

What size thread bolt will I need for an O2 Bung?  I don't have any O2's to check with at the moment.

Thanks Adam

[GSB]

No idea of the size, I've got thread gauges and could have measured it yesterday as I had the O2 sensors out to repair a sheared heatshield bolt.  Oh well...

However, I have just been rooting through a load of bits in my office and have come up with a plug that looks tailor made for the job, and its also just occured to me that I've got a spare manifold in the cupboard, so I can measure the O2 port on that quite easily...

I'll get back to you...

[GSB]

Well, I've measured it, and it looks like a wierd thread. Its not a normal metric thread , fine or coarse, as the threads themselves are simply to close together. Its not any Imperial thread that I know of either. So I looked up the more specialised stuff...

It appears to be a an 18mm "ISO Metric Special" thread, similar (but bigger) to the thread used for spark plugs.

So your looking for a plug with an 18mm outside diameter, and a thread pitch (distance between each thread and depth of each thread) of 1mm.

As I said, wierd size. You may just want to stick an old O2 sensor back in there.

[Anonymous]

I measured mine, came out to be 18mm x 1.5mm

[GSB]

I measured mine, came out to be 18mm x 1.5mm

  s:oops: :oops: s:oops:  You noticed I said "appears to be..."?

He's right, I just took a putty cast of the hole and measured that, (so mcuh easier than trying to see down the hole.) its definitely 18mm x 1.5mm ISO metric fine.

[Jap GT300]

Great, thanks for your help.

I'm in the process of grinding down some 18mm metric bolts!