Opus V12 Distributor Trigger Board Screws

[DoubleBill]

Hi all, new boy question! I'm trying to rebuild the distributor on a series 2 Double Six. This has an electronic trigger board for the fuel injection that is held in place by 4 weak little nylon screws. On removals these have broken off which I understand is a common issue. So...
Does anyone know the size of these screws (are the metric, UNF, UNC?) and where they can be purchased? They are not listed as separate part number in my factory parts catalogue.
Even better, does anyone know of an alternative that has been devised over the years to get around this problem?

Many thanks

Bill

[mike020150]

I can't give you the thread sizes but a lot of Lucas kit around that time seemed to use BA fixings. If you can't buy any from SNG Barratt, I'd try the Distributor Doctor (www.distributordoctor.com/). Mike.

[DoubleBill]

Thanks. I already tried Distributor Doctor to no avail. Researching it more today and I noticed Barratts do an upgraded trigger board kit that includes the screws and rubber isolation grommets so they must be sourcing them from somewhere. I'll get in touch with them. Have also asked AJ6 Engineering but no response so far. My car has been stood 17 years so the original trigger board may need replacing with the new type one Barratts sells as it's the original reed switch type. Does anyone know how to test that the board is functioning properly?
Cheers
Bill

[DoubleBill]

After some digging Barratts found the below kit which doesn't readily show up on the website.

https://www.sngbarratt.com/uk/#!/Englis ... eb88b970f6

The screws (and their grommets) are the brick red and white items in the picture. At £39 its seems massively expensive when the nylon screw are pennies each if I just knew the right size.

Surely someone out there must have had this problem with the screws breaking before and know the size?

Cheers

Bill

[poprivet]

Bill, download Kirby Palms (free) on-line book. Although XJS based, it contains a lot of information on the V12 distributor problems as well as many others things that will also apply to your car.

http://www.jag-lovers.org/xj-s/book/Jaguar.html

[DoubleBill]

Thanks poprivet. Yes I have downloaded that book (what a fantastic piece of work) but it doesn't state the size as far as I can see. It mentions getting around the issue by retapping the threads to M4 so thicker and stronger screws can be used. Ill try that if all else fails.
I've ordered a selection of screws so with trial and error I should get there eventually.

[PaulGover]

If they're BA screws, they're essentially metric, just not the current standard sizes. You commonly meet the even numbered sizes.
In millimeters:
size pitch OD ID
2BA 0.81 4.7 3.73
4BA 0.66 3.6 2.81
6BA 0.53 2.8 2.16
8BA 0.43 2.2 1.68
That might help you identify the size you have.

I've several tins of assorted rusty examples, no nylon ones though.

[DoubleBill]

Thanks Paul. That's brilliant info!