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MG MGB Technical - piston info

Hi there
What do I have? piston stamped MOWOG 529703 and diamond shape stamp with number 2 and 3? One piston have number 3, the others have number 2 so it is not location. The engine is 18mgb h u 11234

Martin
sharpeys

Martin:
If memory serves me; the BMC part number is on the inside of the piston wall. Use that number and compare with Moss Europe catalogue. The diamonds were used to identify 5 sizes of machining tolerances from the block machining site. The pistons were inspected and given a diamond 1 thru 5 identification; consequently the assembly mechanics used matching diamond numbers for pistons & block bores. I seem to remember diamond 1 had the tightest tolerance band.
Rich Boris

Martin,
Genuine BMC parts but this is not a BMC part number. I expect someone will be able to decode a manufacture inspectiondate. Could the single figures be the range of weight?
R Walker

Hi there
Rich, Walker, I now have the BMC numbers, piston is 12H1489 the number 529703 is cast into the skirt of the piston as well. I am also looking for con bearing size 12H2719. The best would be to have the BMC list or location I can copy it from. I need only the engine numbers, as the B engine sits in twin cam body.

Martin
sharpeys

Martin:

Research the following site:

http://blog.earlymgb.com/2012/05/22/resource--factory-microfiche-to-sept-1976.aspx
Rich Boris

yes, Rich is correct on the diamond designation above.
vem myers

This thread was discussed between 19/11/2012 and 28/11/2012

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