Lower front damper castellated nut: 7/16 ?

[Durango2k]

Hi guys,

I am missing the above described nut. I tried to order one from SNG, and got what I think is a 3/8 nut (albeit in a 7/16 plastic bag).

I measured what they sent me, and inside the nut, from thread to thread, it is 9.5 mm.

When I calculate 3/8*25.4 I get 9.525.

When I calculate 7/16*25.4 I get 11.11

So, did they send me a 3/8 nut ? Or is it a 7/16 and I need something bigger there ? Iirc the parts book clearly says 7/16 for it (as does SNG on their website...).

Then, they sent me another too-short exhaust manifold stud. Does anyone have a length in mm ?

Carsten

[christopher storey]

I cannot remember whether the thread on this is UNF or UNC . The UNC is 14 threads per inch, and the UNF is 20 threads per inch so a quick measurement of the threads will tell you. The internal diameter of a UNC nut is about 9.55mm ( there is some tolerance on this so it may be smaller, down to about 9mm) and that of a UNF nut is 10.03mm, again with a tolerance down to about 9.5mm . Therefore, it sounds to me as though what you have is a 7/16 nut, but you will have to decide whether it is coarse or fine

The reason for the differences in measurement is that although the major nominal diameter of the aperture is 11.11mm, the outside thread of the bolt screws into the minor diameter of the aperture , the difference being effectively twice the thread depth . This would be easier to explain with a diagram - I shall try and find one and post a link

Edit : here is a link to diagrams galore

https://www.google.ca/search?q=unf+thre ... Du4QsAQIWQ

[Moeregaard]

The lower damper bolt is 1/2-20, which is UNF.

[Durango2k]

Hm,

Seems I got something wrong here - maybe I mis-read a diagram.

The bolt seems to be C15155, then- and this seems to be 1/2 inch.

Will investigate...

Carsten

[Moeregaard]

I machined lower damper bushings (Jaguar p/n C 9326) for both of my E-Types (the originals are notoriously prone to seizing) from 304 stainless. I just checked my drawing and it is bored to 1/2" ID.

[Durango2k]

I stand corrected. It is a 1/2 inch nut.

Carsten