Was 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.




Updated: 21.10.10
Posted: 14.10.10
Measurements 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 HZA4015 bonnet fitted to that model. More
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 1988
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.

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