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B Engine Numbers

To: mgs@Autox.Team.Net
Subject: B Engine Numbers
From: Williams/MG Guy <mgguyc100@newedge.net>
Date: Mon, 19 Jan 1998 17:13:28 -0700 (MST)
Hey listers...especially those with knowledge of the engine numbering coding
circa '68 - '70 for the MGB...

My reference indicates the following:

1st prefix group - Cubic capacity, make & type
        1st prefix number: 18 = 1800cc
        1st prefix letter: G = MG

2nd prefix group - gearbox & Ancilliaries
Letter: U - Center gear change   R - overdrive RC - automatic
        RWC - Center gear change with overdrive

3rd prefix group - compression & serial number
        H - high comp./L - low comp.

All of this is well and good, yet later the reference piece speaks of other
prefixs, including WE - Center gear change-all synchomesh.

OK, so here's the puzzle. On my '70 BGT, the engine # is 18GH-WE-H 21305
(sic - right off the plate, spaces & hyphens), which sort of makes sense,
18G, then the first H, is that high compression, or is the *second* 'H' that
preceedes the actual serial number the compression 'H'? And the 'WE' is
correct, as it left the factory without an OD. So, if one H is for
compression, what's the other indicate?

This brings me to my roadster. The original engine plate disappeared during
a rebuild, but I did record it as 18GH - WE 4591. As I'm about to replace
the engine ID plate with one from Clarke Spares (thx to all for that
advice!), I thought I'd have the original number modified to reflect the OD
that I'm installing.

Still with me? How then would that read? 18GH-UR-H 4591 (U=center gear
change/R=overdrive), or should it be 18GH-WER-H (WE=center gear change all
syncro/R=overdrive)...OOOORRRR, how about 18GH-RWC etc. (RWC=Center gear
change with overdrive).

Such a dilema. Can anyone with a circa late '68 to end of September '69 OD
equipped car check to see what the correct sequence of letters that were
used might be?

Thanks for any insight.

Terry "Got a Code In My Head" Williams
'70 BGT
'68 roadster


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