I’ve been offered a 1974 head (S-2?) to replace the damaged 1971 head (S-1)
on my XJ6. It is from a UK spec donor car.
Does anyone know if it will fit without modification?
I think UK spec cars were a higher compression ratio than the US cars. If
so, would that have been done with the piston shape or the head, and does
that matter in my case?
The head will fit but check for two extra coolant passages at the rear of
the SII head, the SIIs had them but I’m not sure about the SIs. If you have
the SI head off the car it’ll be easy to check. If the SI block doesn’t have
the two extra passages the you’ll have to block the ones in the SII head or
get a SI replacement head.
The compression ratio difference was achieved by using different pistons so
your compression ratio should be the same whatever head you use.
Regards and Happy New Year,
Jeff Watson.
Sydney, OzSubject: [xj] S-1 vs. S-2 head
All:
I’ve been offered a 1974 head (S-2?) to replace the damaged 1971 head
(S-1)
on my XJ6. It is from a UK spec donor car.
Does anyone know if it will fit without modification?
I think UK spec cars were a higher compression ratio than the US cars. If
so, would that have been done with the piston shape or the head, and does
that matter in my case?
In reply to a message from Jeff Watson sent Thu 30 Dec 2004:
Hi Take the head gaskt from the ser I car and fit it onto the ser
II head, you will see if your head matches the block. But if you
have extra holes in the head or the block you can block them off
with a couple of small freeze plugs. You go to a parts store that
is also a machine shop, ( we have them here like that) and tell the
man at the counter you need 2 freeze plugs and I think they are 5/8
in size clean the holes locktite them or silicon them I have done
them before it works Cheers Pajtas–
jaguarjoe 54 XK 120 rdstr 1961 MKIX 94 XJ6
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