Can anyone shed light on the period usage of the exhaust cam cover in the attached photos, C8728? The part number is not listed in the Spare Parts Catalogues of any road cars and with the breather vent its origin is presumably the competition department?
A summary of XK cam covers:
Early A Type studless head (C.2242): Covers C.2217 (Inlet) & C2218 (Exhaust). 2 studs at the front.
C Type racing: Covers C6722 (Inlet) & C6723 (Exhaust). 3 studs at the front of the head; the outer 2 have 1” boss.
Later A Type head (C6733): Covers C7185 (Inlet) & C7186 (Exhaust). 3 studs at the front, all with 1/2“ boss.
XK140 MC Head (C7707): Covers C9738 (Inlet) & C9739 (Exhaust). The same casting as C7185 & C7185 with added C Type badges (2 or 3 pins).
XK150 B Head: C14987 (Exhaust). Replacement for C7816. Take off for electronic rev counter.
The first reference I have found in Jaguar literature for C8728 is in the J.12 Master Parts Price List, 2nd Edition, Cumulative Supplement No 2, March 1957:
C8728 - Price on application
No description of the part or price is given; just the part number. March 1957 would suggest D Type?
Interesting to know if this part and the number has been previously identified?
simon,
can you provide a better pic of what is down the end of the cam cover.
the screw in fast action flip top is a standard Enotts part of the day ie they can in say 2 3 and 4 inch and I have one of these that screws straight into the threaded section. Being a separate part my guess is that it would have had separate part number not part of the CC8728 part?
terry
just point on the Cam covers generally considered to be from the C type with the 1 inch boss.
I have an XK120 roadster built june 1952 that had these, car was never in contact with a real C type so assume fitted at the factory?
Yes Terry, covers C6722 (Inlet) & C6723 (Exhaust) with 3 front studs (inner 2 with 1” boss) were fitted to XK120s with engines W4691 - W5652. So, April - August 1952.
The C Type racing cars had the same exhaust cover (C6723) but the inlet part number is not the same; C5889. Possibly the hole for the breather vent, towards the front, accounts for the difference?
OK not something I had picked on that there were details of which motors had them.
certainly had assumed that they would be fitted to a batch of engines about this time.
So in theory there are some MKVII’s with them?
So there are at least 1000 pairs out there!
The engine numbers (W4691-W5652) for the 3 stud cam cover with 1" bosses are listed in the XK120 Spare Parts Catalogue.
The same cam cover part numbers are listed in the J21 MK VII Parts Catalogue, for engines A6959-A7001 & A7027-A8914.
These engine numbers are in-line with those of the change to the cylinder head with 3 front studs (C6733). So just under 3,000 (961 XK and 1,929 MK VII) of the first 3 stud cylinder heads had cam covers with the higher 1" boss.
