Hello all! If the Mini engine have a bore x stroke: 85.8mm x 77mm bore, how did Mini/BMW come up with 1598cc (1.6 Liter)? Shouldn't it be a 1781cc engine (1.8 Liter)....

 

i used an online displacement calculator to figure it out...

Engine Displacement Calculator by Bowling and Grippo

Input Parameters Are the Following:

• Number of Cylinders are = 4 to 1
• Piston Diameter = 85.800 Millimeters
• Piston Oversize = 0.000 Millimeters
• Engine Stroke = 77.000 Millimeters

Computation Results:

Computed Engine Displacement (CID) is 109
Computed Engine Displacement (Litres) is 1.8
Computed Engine Displacement (CC) is 1780.8




I wonder what there smoking over there in england...

 

Also, speaking about the +05 Cooper S W11B16A factory valve. BMW/Mini service manual says:

Intake OD Valve: 31.9mm
Intake Stem OD:
Exhaust OD Valve: 25.2mm
Exhaust Stem OD:

My buddies at Ferrea say's it's nowhere near that size??? Guess, I will have this measured with a friends motor out for built up.

 

i just checked some s valve i have and they measure 30.2mm for the intake and 23.2mm for the exhaust. i believe the head was off an '05+ but not 100% sure.

 

New & confirmed update on W11B16A specs:

BORE: 77mm
STROKE: 85.8mm
DISPLACEMENT: 1597.6cc (1.6 Liter)
R/S Ratio: 1.56
MPS @ 7000rpm: 20 Meters per Second
MPS @ 8750rpm: 25 Meters per Second

Intake Valve OD: 30.25mm, Stem OD: 5.95mm, Overal Lngth: 109.5mm
Exhaust Valve OD: 23.25mn. Stem OD: 5.91mm, Overal Lngth: 118.3mm


1597.63

 

Total CID is determined as follows: Bore x Bore x Stroke x .7854 x (no. of cylinders).