Series 3 Glow Plug Thread and Pitch size

[Llew]

Some help please, I am looking for the thread and Pitch of Series 3 glow plugs. I am wanting to do a compression test, but none of the adaptors I have fit either the glow plug or injector, so will have to knock up an adaptor.

I have done some searching but just cant seem to find anything definate, obviously a set of thread gauges would help but havent found a local shop that stock them.

Thanks

 

[dr pepper]

I seem to recall that they are a non standard form of whit, with a diffo thread angle.
Probably the best way to tackle the issue would be to attack a standard glow plug with a drill and welder to make up your adaptor, the sticky out glowy bit of the glow plug if not present will make a diffo to the compression, there isnt much room in the chamber and loosing it will lower the compression a little, but you'll still get a good idea and you'll be able to compare readings.
You will be able to get a thread guage online, mine came from RS components.

 

[Llew]

Cheers for that. I went to a machine shop and they are basically knocking up a dummie glow plug with a compression adaptor welded into place. The machinist aid that the thread was non standard but would let me know what exactly it was once he had finished the component.