First off, I have to say that I haven’t tried to find anyone who can do this job, but I would surprised if nobody can be found. It’s a relatively standard operation but I suppose with modern computerised production the set up might make it prohibitively expensive.
If you’re in the UK and get completely stuck I would suggest contacting David Knight Engine Services near Daventry, who have been performing machining jobs on XK engines and heads for decades. Talk it through with David who will, I’m sure, be happy to advise. The trick is to find a machine shop that is flexible, rather than doing contract production work. I’m sure there are plenty of other shops to try. If I can find shops that will do bespoke white metal bearing work, this sort of alignment work should be straightforward by comparison. It’s the size of the tooling that might be problematic.
As a second option, it’s worth exploring the selective assembly route. Given the mass manufacture of these parts, it’s possible that one set of caps would fit pretty well on another head. A set of shells is not too expensive, so maybe try the slow and careful assembly of a cam, one nut flat at a time, turning the cam by hand each time to see if it’s going tight. If you get to the right torque setting and it’s not binding, maybe dismantle and reassemble with some engineer’s blue to give an idea of excessive contact areas?
On cams - I have fitted a pair of Newman PH1 cams, which are their standard replacement for the roadgoing unmodified engine with SU carbs. Close to the original SE cam but with very slightly higher lift and a gentler ramp. One advantage of these is that Newman state they do not need a cam break-in procedure at initial start-up.
Another thing to bear in mind is that if you have a conventional line bore done on these caps with the joint faces machined to reduce the starting diameter, your cam bearings will sit very slightly lower in the head. This would affect the valve clearance settings to some degree, but I don’t think it would be a problem.
What is late?
I don’t think so. But my block (1969) is not stamped next to the main bearings; someone forgot. And my caps are stamped 1234-5768. Wasn’t a high priority it seems.
I would not ask for a line bore for an xk head at first but give dimensions and add that there’s only so much space at the chain end. I‘d probably say no to an engine I don’t know but be curious to try if I heard dimensions first?
If you require align honing Classic Jaguar in Austin Texas list it as a procedure they do on engines and heads that require it. It may be only available with full rebuilds but worthwhile contacting them if you require it.
Hello Robert - Thanks for tuning in. As I see in the catalogue the cams for a XK140 OTS 1955 are numbered C.5717 for Inlet and C.5718 for exhaust. They are not super rare but the originals have these numbers stamped on them for authenticity.
Cheers - Geoffrey
Hi Roger - thanks for this. I will just check out David Knight in the meantime. I would prefer to use genuine Jaguar parts but I will look at the Newman range anyway. I intend to go down the H8 carbs by SU route so I was thinking if cam profiles need to be different to get maximum yield. I do not want a super fast car but one that is suitably balanced with this period H8 option.
Cheers - Geoffrey