winabbey wrote:
Bubbacluby wrote:
Doug have you found any markings on your head?
I haven't removed the head and it's covered in grease and dirt. After a quick clean just now I can't see a Lynx marking in an obvious place. It does have the 12G1805 factory stamp near the thermostat and a couple of indistinct markings on the flat areas at both ends. I'll have another look when it's removed and cleaned.
Managed to do a bit of grease and dirt removal on the head so here's some pictures.
It looks to me like a stock standard MK II Cooper S head - casting 12G940 with part number 12G1805 stamped on the flat near the thermostat housing. According to the SPO41 specification it should have Special Tuning double valve springs and retaining collets but I haven't confirmed.
Attachment:
Cylinder Head 31.jpg
Attachment:
Cylinder Head 21.jpg
The previous owner purchased the car from the NSW Govt. auction and used it as his daily driver until 1991 when the clutch apparently failed and he parked it. He confirmed the engine was rebuilt once with standard parts and the head surface skimmed by Mendham Engineering in Brisbane, but otherwise no significant change. There's an ME and serial number stamp at the back of the head to confirm this.
Attachment:
Cylinder Head 5.jpg
Internally the ports don't appear to have had any polishing or other work done. The usual manufacturing clean-up to remove rough edges during original head production is there and can be seen as a sort of half-moon adjacent to the inlet manifold locating ring in the photos below. The rest of the port in to the valve guides is still rough cast so no porting done there as far as I can see.
Attachment:
Cylinder Head 10.jpg
Attachment:
Cylinder Head 15.jpg
Regarding other stamping marks, there is the letter A near the 12G1805 stamping that research indicates is a BMC quality control inspection mark. Other letters mentioned on international forums are K, R, S and Z. At the heater outlet end there is a letter Y, or three pointed star stamp, like a Mercedes logo without the circle. Also a partial number 2 stamped on the face near the centre stud hole. I don't know what these indicate.
Attachment:
Cylinder Head 24.jpg
Attachment:
Cylinder Head 2.jpg
Comments welcome.
