Cylinder Head Query

[Ruairidh Dunford]

The photo is from an Association Magazine article if I remember correctly.

I have been told that although that head looks very similar there are differences, early supercharged engine owners/experts may well be able to confirm this...

[Chris KC]

The profile of the combustion chambers looks ever so slightly different between these two pics? And I'm wondering whether that water take-off is integral or bolted on?

Either way it looks covetable! Would be interested to know how it performs.

[Ruairidh Dunford]

The profile of the combustion chambers looks ever so slightly different between these two pics?

I think that is it too Chris.

[Chris Garner]

Water take off is bolted on. 
Source book, page 272  "During 1931 an alternative head became available with improved cooling.. & raised compression ratio of 7.1 "
The cast letters etc., we believe, read 9C71

It is planned that the head be trialed on a recently built blown engine.

[Ian Williams]

The 9C may be our clue to parentage of the casting, the grey matter is not as good as it was, but if I recall correctly the competition conversion parts were all originally numbered 9C later they were numbered 9E, much like the XL and IA numbering on std components. ( not sure when the change took place but could coincide with std components around 1927) However unlike the std components the 9C parts always carried the same prefix even when they remained in use after the introduction of the 9E numbers, all very academic I know but I find these things interesting. As you may recall I did a study of early std LC heads and found at least five different combustion chamber shapes and volumes all on unskimmed heads. I see no reason why the factory would not make subtle variation on the chamber of competition heads when used in a different application, i.e Brookland's, Super Sports, and blown Ulster. I anticipate we will see the same 9C number on all three and will be interested to see if I am right or wrong in my assumption.

[Hugh Barnes]

The photo was taken by Sue Walker (nee Young) and I suspect would have been taken for the 72 Longbridge Golden Jubilee so was probably a display item at the event