2 replies to this topic

[unionjacques]

Hey all.newbie here and looking for help.
my mini has a metro engine in it , numbers 12HD24129454.
I've recently replaced it with an unleaded head number 12G940B.
Can anyone tell me about these heads?
thanks.

[Dom]

im afraid i cant but someone will shortly

hello and welcome to the mini forum

try posting this in the tecnical and problems section

[Dan]

The number on a cylinder head is just a casting number. It refers to the bare casting the head was machined out of. Many different specification heads are made from each casting to fit many different specification engines. There are no other identifying marks on heads, the only way to find out what spec your head is is to measure the various different machined parts of it. The valve sizes and types, chamber volume, total height of the head and the amount of port work may all be different. Unless you know which engine the head came from originally?

The 12G940 casting was fitted to the 1300, the 1275GT, all 1275 A plus engines (including all turbo engines), the MG1300, the 1300GT, the Mk3 Cooper S, and the MG Metro among others so there's a few different specifications for it.

As for your engine number, 12HD24 is one of the engine types for the MG Metro up to 1989 which means it's four star only. But of course that may have changed with your new head, again you are going to have to know more about the head to tell if it's unleaded or not.

The last 6 figures of your engine number are just its serial number and don't help identify it. 12 means 1275, H means horizontal (transverse fitting) and D24 is the build code.