Valve Guide

Valve guide material Cast iron (Brico Alloy 2 or BS 1452/12
Inlet valve guide length 47.24 mm (1.86 in)
Exhaust valve guide length 49.53 mm (1.95 in)
Outside diameter (Both guides)
Standard 12.725 - 12.751 mm (0.501 - 0.502 in)
First oversize 12.776 - 12.802 mm (0.503 - 0.504 in)
Second oversize 12.852 - 12.878 mm (0.506 - 0.507 in)
Third oversize 12.979 - 13.005 mm (0.511 - 0.512 in)
Interference fit in cylinder head 0.013 - 0.056 mm (0.0005 - 0.002 in)