I think all XK and V12 caps are the same thread, none are bayonet. The size difference is illusory.
This is due to some having flat sealing faces with a washer (hole appears small) and others having a female taper in the cover (appearing larger) for an o-ring seal. The caps themselves interchange in terms of threads, as do the ‘bar’ caps…
I just tried my 3.4 cap to 4.2 all the same thread
Thanks for the backup Pete
Gtjoey1314
Yeah thats discontinued now…
I got mine from sng. It’s alloy vs chrome, (which I understand some are). One of the things I like is that I can add oil to a hot engine without having to unscrew the OEM cap when it’s hot)
Well I have one coming from SNG
Let’s see
Something to make life easier
Hi Joey…does the sng cap come with a screw in adaptor…it dosnt mention it on the sng website…Steve
Yes it does, its not a weld in deal.
Hi Joey…not sure i explained what i ment correctly. …most of these cap have an internal female thread…the cam cover also has an internal female thread…so u need an adaptor to join the two…does this adaptor come with the sng cap…Steve
Yes it does…gtjoey1314 ask for will…at sng
SNG shows it available, but when you specify a S1, it doesn’t show up. Thinking it may interfere with theS1 covers instead of S2 with are flat.
I’ll get it
Report back as usual and give a fair observation
Looks neat, if in person it looks goofy I’ll tell you
There’s a gasket then a screw in ring then the cap
I’ll move the cap on every direction to see how it fits okay
It should be here in a week or so
There are others out there a tad lower but they have to be welded in
Hi Joey…sorry to repeat this again but just trying to ensure you get what you want…im assuming you have ordered C1022monza…this has a threaded ring inside…but you do need an adaptor to fit it to the cam cover…the SNG part number is C1022-B
I told Will to
Usually he isn’t as dumb as the rest of the people these days but yes…
Now it’s still 70 /30 the order comes in wrong, broken , stuck in customs and along with local mail and door package theft
I’m staying positive😀
Well at least the info i posted above should be usefull for anyone else as it gives both part numbers that need to be ordered…approx £110…Steve
Thank you my friend but your repeating
Like my wife locked up on the house with large bottles of wine…
Let’s see if this piece of kit even leaves the UK
Having fun…
Gtjoey1314
P.S. I’m getting the Monza cap , with the adapter screw in sleeve a kiss from Will at SNG and probably a dent in my bonnet😀
If you put clay on top of the Monza cap it should help prevent any dent if you lower the bonnet very carefully and then verify your clearance (if any).
Thanks John will do as per other John as well.
I seem to have alot of room, plus the angle but we shall see, Ill turn it in every direction to see if one side is closer.
gtjoey1314
I want to Thank MGCJAG, My buddy Will went on vacation, so I double checked my order…
Thanks again as I would have had just the cap AND NO GASKETS…
It never ends…
Ill take care of Will when he returns. 
gtjoey1314
Joey, I used Teflon tape on the threads between the adapter and the cap. The adapter itself uses the same rubber gasket as the OEM screw-in cap.
