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Re: B Engine Numbers

To: "Williams/MG Guy" <mgguyc100@newedge.net>, <mgs@Autox.Team.Net>
Subject: Re: B Engine Numbers
From: "David F. Darby" <darby@tri-lakes.net>
Date: Mon, 19 Jan 1998 22:41:18 -0600
Hello Terry:

Your GT has a GH series engine which is correct for Oct 68 -- Aug 70. The
first MGB 1800s were 18G (1962-64), then came 18GA, GB, GC..., GH, and so
on until the 18V series (1971-80). So the first H is just part of the
engine series designation.

Had your roadster rolled from the sacred halls of Abingdon with overdrive
it would have been designated 18GH - RWE-H 4591. The R denotes the Laycock
overdrive.

My primary reference for all this is Clausager's *Original MGB.* You know,
it might not be too healthy to know all these numbers. I'd be careful.

Regards,

David F. Darby
Ozarks Highlands, Missouri, USA

----------
> From: Williams/MG Guy <mgguyc100@newedge.net>
> To: mgs@autox.team.net
> Subject: B Engine Numbers
> Date: Monday, 19 January, 1998 6:13 PM
> 
> 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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