WARNING...long answer.
Baker, G. wrote:
>
> To Those Who Know All,
A) Who you calling a 'know-all'??
Bloody cheek!! Us Brits have sensitive feelings you know.
> On inspecting the block of my 56 A I notice stampings on the panside of
> " 7
> 67
> 60"
A) I am assuming that 'Pan side' means the sump face of the
cylinder-block, that machined flat for the oil sump pressing to bolt up
too.
Right, IMHO the story of Greggs block goes like this........
Once upon a time, in a big smelly, hot factory in Cowley, Oxford,
England, a pattern-maker fitted out a sand-mold in the foundry with a
pattern for the 1200cc/1489cc BMC standard cylinder block. Once cored up
and placed onto the long line of dies waiting to be filled with moltern
grey cast iron, it took its turn. Once cooled down, it was passed to the
de-flashing area, where the casting was broken out of the die, or mold,
( or even mould in my dictionary,) and cleaned up with a sand-blaster.
Core holes were emptied of the sticky sand using angled chisels.( The
core is the internal holes, like waterways,etc.)
Once clean, the new casting was placed on the end of one long 'transfere
machine' run. This complex set of machines carried out virtually all the
machining of the block, automatically, with only two attendants to bolt
on, and unbolt the finished item. On this run the block might be bored
to 65.4mm for the 1200cc version of the 'B' series, or to 73mm for the
1489cc of that engine, or even 75.4mm for an limited edition of the MGA
twin cam version. Greggs engine is one of the 1489cc versions.
Only after all the machining are the various cylinder blocks put onto
separate assembly lines in the Engine Assembly Shed. As Greggs is a 1956
version, (by then BMC only made the 1200 version for Ireland,) and cast
into the side of his block will be the large figures "1500". The smaller
engine now had "1200" cast into it, for easier identification.
As the engine block passes down the line, various numbers will be
allocated to different 'makes' of BMC car. Anything with a 'G' stamped
in will be for MG, 'R' for Riley, 'W' for Wolseley, 'A' for Austin, and
'M' for Morris. In actual fact, there were only three types, 'G', 'R',
and 'AMW', these last three sharing the same engine.
Greggs engine is selected for a MGA, it will finish up with an engine
number prefix of BP15GC with 68bhp, or after 1956, BP15GD with 72bhp.
The 'B' stands for 'B' series, the 'P' for pushrod, 15 for 1.5 litres
class, 'G' for MG, and the 'C' or 'D' is just the modification state.
( The 1789cc MGB engine got as far as 'GJ' from 'G', GA' etc.)
As a future MG engine, the block would get a suitable camshaft, pistons
with FOUR thin piston rings with solid skirts,( normal engine three
thick ones, with a split skirt,) harder big end and main bearing
shells,and a suitable cylinderhead with bigger valves. The bores were
measured, and pistons graded,( by half-thousandths of an inch,) and
often the grade was stamped on the lower face of the block, ( the sump,
or pan.) Otherwise, appart from a stronger oil relief valve spring, the
engine shared everything with the hum-drum unit the other 5,000,000 BMC
models using it. ( Good for spares supply, keeps costs down.)
> Also saw stampings of "GG".
A) Probably means 'Engine for MG' as above, readable with the block
sitting upside-down on the head-face, on the assembly line. For
assemplers to put the correct parts inside.
> Does anyone know what they refer to and if they are indeed factory stampings?
A) They probably are factory stampings as explained above, but
reconditioned engines get extra letters from within that firms own
system. For instance Morris Engines rebuilt 1489cc 'B' series, as
'Gold-Seal' replacement engine. ALL OF THEM had the prefix 48G, which
simply meant reconditioned engine, nothing to to with MG, ( Midgets were
8G, and MGC 68G, reconditioned.)
> There are also two allen head plugs of different sizes in the block panside
> surface. Are they oil galley plugs or what?
A) There are two hole diagonally opposite each other, used to locate the
cylinder block on the transfere machine lines accurately. These are
about 5/8" diameter. Do you mean those? Otherwise, they will be oil
gallery plugs, there to be removed for cleaning out.
> I ain't got a clue as to the numbers.
> Thanks for the responses.
A) Not at all, old chap.
> Gregg Baker
Neil.
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