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MG MGB Technical - Engine Numbers
|I have a 1968 mgb roadster the engine has the following nunbers 48 528 AD I believe the 48 represents that it was a factory exchange unit. Is this correct and does anyone know what the other numbers and letters mean. Thanks all John|
|It seems that no one else is sure about the numbers on my engine. Seriously if anyone can help pleeeeese it would be appreciated.|
Clausager's Original MGB, page 69 has a part of the info you seek. It shows that a 48G 528 was a replacement 18GD/GG. The 18GD/GG was a high compression engine with a manual gearbox per the chart. Upon cross referencing to the Production Changes in the back of Claussager's book it appears the engine 18GD/GG would be from the general era of 1967 to 1969. (GD started mark2, november '67. GG was introduced in Oct, 68.) Hope this helps.
|Thanks Paul I am still some what confused it seems that my engine is definately a replacement but are you saying it is after 1968 or earlier. Also any idea what the AD means.|
|Between 67 and 69, so definitely right for a 68 model. I don't think anyone has adequately deciphered all the Gold Seal numbers, at least not that I have seen anywhere.|
|Thanks Guys the puzzle is comming together.|
|The letters at the end of the prefix usually indicate options and specification. For example an 18GG or GD could have R for OD, RU or Rc for auto, We for manual with 1st gear synchro, and H or L for compression. The 48G 528 was the high compression, manual gearbox with synchro 1st version of the 18GD or GG, so maybe the AD is something to do with OD.|
|Paul Hunt 2|
|Thanks PH and others for your help.|
|I have a related question.|
My 70 roadster's engine plate is worn to the point of being almost unreadable. I've tried both making a rubbing and covering the plate in ink and rubbing off the high spots, but the best I've been able to determine is 18GJ-WE-H/xxxxx.
The 18GJ makes sense for a 1970 US model, as does the H for high compression, but my references don't show the WE. Paul's comment above was the first I'd seen of the WE code. Was that the same for the 70 model year (car was produced 1/70, chassis number GHN5UA...)?
Also, was it normal to have hyphens (-) vice slashes between the groups and a slash (/) separating the compression from the serial number?
|S. M. Chafian|
|Slashes, hyphens and spaces seem to have been 'optional' i.e. varied and sometimes confusing, to the point where a slash is sometimes taken as a digit 1 by registration authorities and similar errors. According to Clausager the 'We' option i.e. 'manual gearbox, centre gearchange, synchro on 1st' could be applied to any 18GD to GK engine from 67 to 71 i.e. all 5-bearing 18G engines. Before 67 i.e. 3-bearing 18G engines the 'We' was replaced by a 'U' which signified the same except 1st gear *not* synchronised. After 71 i.e. 18V engines all gearboxes were synchro 1st, there was no alternative to centre gearchange (i.e. column change which was quite common on earlier BMC saloons but no longer available anywhere in the vehicle range), and engines with auto boxes were signified by a different prefix number i.e. 583 instead of 582, so the alpha-character signification of this option was no longer required.|
|Paul Hunt 2|
Thanks so much. Evidentally Clausager needs to be added to my library!
|S. M. Chafian|
This thread was discussed between 03/01/2007 and 12/01/2007
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