Exhaust manifold stud thread pitch

[Bristol_Jer]

I went to put my manifolds back on my engine and a couple of the threads don't feel right so want to clean them out and run a tap through them to make sure they are ok.

BMWfans lists the studs as m8x40, and a quick google suggests the pitch is 1.25. Does that sound right? I haven't got one in that size so would need to order one.

(It is on an m30, but same stud part number as m20)

Cheers

[wullie325i]

don't know the answer mate but a thread gauge costs nowt really so well worth the purchase if your doing stuff like this.

[Bristol_Jer]

That's very true mate, I should have one in my tool box really, will get one.

[Brianmoooore]

Get yourself a set of thread cleaning nuts. Similar to thread cutting dies, but with a hex. outer shape. Stud thread is a 'standard' metric thread.