Auxiliary/ Extra air valve

[richard.whittington]

Hello All
Unfortunately I have misplaced or lost my auxiliary/extra air valve control screw.
The part no. Of the air valve, which includes the screw is EAC 2773, that was fitted, I believe to the XJS HE.
To buy a replacement valve would be quite expensive , when all I require is
sufficient information for me to buy or make a replacement screw.
Any assistance would be very much appreciated
Kind Regards
R Whittington

[davidr]

Hi Richard - I have an AAV that I cut up for an autopsy and subsequent magazine article that we published in August 2018. Why? Well if you leave a bloke alone with a disc cutter its inevitable!
Here are the parts that I cut up.

I have a thread repair kit which as well as its obvious job is also very useful for working out a mystery thread. This kit is not very expensive and its one of the most useful things in my workshop.

The idle screw has a peculiar thread. Its very close to 1/2" UNC but binds up after a few turns. Its closer to M12 x 1.75 but again binds up after a few turns so I'm not sure what it is.

So I fear I've not helped you much. Of course ,what I do have is a spare idle screw and you're welcome to that if you send me your address. You can either pm me here or my contact details are in the masthead of the XJS section in the magazine

[PaulGover]

According to Kirby Palm's book

On this author’s ’83 (as well as in the photo), the adjuster is a 12mm thread with a head barely larger than the threads, so
the head requires a 13mm socket to fit. However, Craig Sawyers reports that later versions (including replacement
valves to fit earlier cars) use a metric threaded adjuster with a much larger head: “The old one is indeed metric, M12,
but metric fine thread. It is however a special, with a 13mm AF head (standard is 19mm AF). New valve 12mm over
the threads, 1.75mm thread pitch and 19mm AF. That is a standard metric M12 bolt. Truly huge by comparison.
Jag/Lucas have clearly economised by using a standard M12 coarse thread bolt with the standard head. Adjustment
sensitivity with the coarse thread is just fine.”

What's really annoying is I had a broken one I could have measured sitting on the shelf and only threw it out late last year.

[steve_m]

I threw an old one out last month!

[richard.whittington]

Great news
Do you think that you could find it?

[steve_m]

Yep, it's in the metal bin at the recycling centre.
Which is unfortunately closed for some strange reason otherwise I would be straight over the safety rails and straight in there.
Wouldn't be the first time.
Last time got a really lovely rock for the garden.

[richard.whittington]

I think that continuing this conversation may get one of us into trouble bye

[davidr]

The pictures I took were today. That screw is sat on my workbench. Yours if you want it.

[steve_m]

Jeez, lighten up.

[richard.whittington]

Sorry Steve, no offence intended
K Regards
RWhittington

[steve_m]

None taken; anyway, that was in France where they are much more lax whene it comes to Health and Safety!