the profile of an MGB bonnet changed for the MGBGTV8?
As a double-check as to whether the profile
or curvature of the bonnet was changed for the MGBGTV8 model to give
greater clearance for the V8 engine and ancillaries, two members have
measured the curvature of an early MGB bonnet and that of an MGBGTV8
bonnet and report their findings .
See the earlier item on this topic. More
What did George Wilder learn from Don Hayter?
During the recent MG80! celebrations at Club Office, George met up
with Don and discussed the bonnet query. Don said new tooling was
needed for the steel bonnet for the MGB Roadster and MGBGT as the
previous tooling had been designed to handle the characteristics of
the aircraft grade aluminium sheet used for the original bonnets for
the early MGB models. He added there was no change in the profile
of the bonnet fitted to the four cylinder MGB models or the bonnet
on the MGBGTV8.
HZA4015 bonnet fitted
to that model. More
of the curvature
George Wilder, with an early MGB Roadster with an aluminium
bonnet HZA401, has taken measurements and so has Victor Smith
with a steel bonnet HZA4197 on his MGBGTV8. The results do indicate
a slight increase in curvature on the later bonnet. George hopes
to get a fellow member with a 1972 MGBGT to measure the
The measurements show the vertical offset measured from the centre
point on the windscreen side of the cross brace is 5.1cms on the MGBGTV8
bonnet whereas it was measured as 4.8cms on the aluminium bonnet of
the early MGB Roadster. The difference of 3mm, or just under an eighth
of an inch, does seem to be a very small increase in curvature, even
at the centre of the bonnet. As a further check the position of the
cross brace was measured and in both cases is the same distance from
the bonnet edge by the windscreen (the lower edge of the bonnet in
the photo above).
What do the books on MGBs and V8s say?
George Wilder's research shows:
MG V8 -Twenty-One Years On by David Knowles
Page 32: At the bottom of the LH column he notes "the clearances
were sufficiently tight that it was decided as a precautionary measure
to retool the MGB bonnet to provide a slightly sharper curvature,
and hence greater clearance." George Wilder feels it is more
likely a reworking of the existing tooling in practice.
Clausager Original B
Page 15: The captions with the pictures state that the V8 bonnet is
the same as the 4 cylinder bonnet except for the cut outs in the sound
deadening panel. George says "I suppose this is true but the
book does not mention the retooling for the V8." George Wilder
feels there was one bonnet tool cost and the BL attitude would have
been it was a minor change, however this change is not listed in the
back of the book under the production changes.
Wood and Burrell The Illustrated MGB History
Page 169: the first paragraph refers to modifying the bonnet for the
V8 and sharing it with the four cylinder car and also mentions a similar
exercise with the earlier MGAs.