63 S1 3.8 OTS electrical questions

Does anyone know what screws are used to screw the fuses to the firewall?

According to the Jaguar Parts LIsts, there are 4 screws (UFS.319/4H), each with a shakeproof washer (C.723/A). UFS.319/4H decodes to a UNF setscrew with a slotted cap head, 3/16" diameter, 1/2" long - so a 1/2" #10-32

perfect, thx

I tried going online for “jaguar parts list” and all I get are ads. How can I find this list?

It is officially the Spare Parts Catalogue. One option is to go to JCNA.com. Click on merchandise, factory parts catalogues. Go to page 2. The one you want for a 1963 car is J.30. for the 3.8 Etype. It is a high quality reprint. If you haven’t used one, there is a little bit of a learning curve but we are here to help.

Which is the appropriate hole to send the wiring back to the right and left taillights? I learned in physics that you can’t push a rope. Any suggestions on how to snake the wiring back?

Where do I find a decoder ring?

Okay, where do I find the decoder which describes what Jaguar parts number actually is?

As I am working on my XJS, I am slowly (very slowly) making decoder notes on my parts book pages: grade, size-threadXlength, head type and wrench size, and torque for specific locations as I find them (many are in the ROM under torque specifications, but not all are listed there).

Check out this thread - it has a link.

Okay … I need help as I’m not getting what you are describing.

Please decode, and explain, the bolt in the attached.

I guess I just need to be walked through it, thank you.

I found these codes some time ago but I do not know the source. i hope they help
ShopBook-Fasteners.pdf (80.3 KB)
I have another in excel workbook format however it appears that i can not upload it to the JL forum.

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It appears in your diagram that numbers like BH605401 are just part numbers and are not encoded so to speak. My experience is that the Etype numbering for fasterners falls into 2 camps. One is decodable:
UFS.131/7R is a fine thread fully threaded 5/16" diameter hex head bolt 7/8" of an inch long.
One is not: C17469 is special to the extent that they couldn’t “encode” it so it gets a unique part number. (These are just examples I picked out of the SPC at random). If the number is in the decodable format great. If it is just a part number, I sometimes get lucky by Googling “Jaguar Part Number xyz” and one of the returns will actually list the parameters of the part. Or sometimes I even get a return of a J-L thread where someone asked about the part number and someone replied with the details!


The decoder only addresses common fasteners that were used extensively on the cars. In addition to these, there are many “special” fasteners that Jaguar simply assigned a part number to - these have a “C” or “BD” prefix followed by a number. The numbers are just sequential, with no encoded information about the part.

Harvey and David, thank you, and that is what I am finding with the part numbers for bolts and screws I’ve tried to look up so far.

I was trying to make sure that I am not “recreating the wheel” by my scanning in part catalog pages and adding descriptions to bolts and such to parts I am removing.

I have a sample (of a page I’ve started working on) on my old computer, which is now in the garage for use there. I’ll add that page when I’m back in the garage.

Edit - Added image of page I have put some information on:

Would it be out of place to ask why this is important? All fasteners have a purpose, but to make something special about this goes to extremes.

During a restoration many, like myself, enjoy the challenge of restoring the original items or replacing them with OEM or exact matching items.
Its a very rewarding sense of making things the way they were.

Not at all … as long as you follow with asking ‘why do people have parts catalogs’.

I used to have catalogs as a kid, and I grew up and realized that back then, I could not afford any of the things in them that I thought I wanted. I have seven cars now, and drive three of them. I don’t care a wit whether they have the correct oil or filter, or lug nuts or tires. I enjoy them as drivers and as possessions, but don’t obsess over them.


Clearly not an E-Type diagram, but is it from a Jaguar manual, or perhaps from the SNGB catalog? I ask as I have the impression that Jaguar may have changed the part numbers for the same fasteners over the years. In particular the BH6xxxxxx and SH6xxxxxx series of parts are references I’ve seen from SNGB and may be their own system. A little reverse engineering from the SNGB catalog suggests that aH60bcd1J is decoded as follows:
a - B bolt, S setscrew (is bolt with no grip length)
b - thread diameter in multiples of 1/16"
cd - length in multiples of 1/8"
A bit more analysis may give a more detailed decode.

Do you work on them yourself?

If so, you must be one of the few who have a memory sufficient to know it all.

I acknowledge that I don’t know it all, or even as much as the many here do.

David, 1983 XJS, my parts book is for the XJS, and is from March 1983.